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** This file is part of Qbs.
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****************************************************************************/

#include "moduleloader.h"

#include "builtindeclarations.h"
#include "evaluator.h"
#include "filecontext.h"
#include "item.h"
#include "itemreader.h"
#include "language.h"
#include "modulemerger.h"
#include "qualifiedid.h"
#include "scriptengine.h"
#include "value.h"

#include <language/language.h>
#include <language/scriptengine.h>
#include <logging/logger.h>
#include <logging/translator.h>
#include <tools/error.h>
#include <tools/fileinfo.h>
#include <tools/preferences.h>
#include <tools/profile.h>
#include <tools/profiling.h>
#include <tools/progressobserver.h>
#include <tools/qbsassert.h>
#include <tools/scripttools.h>
#include <tools/settings.h>

#include <QDebug>
#include <QDir>
#include <QDirIterator>
#include <QPair>

#include <algorithm>

namespace qbs {
namespace Internal {

class ModuleLoader::ItemModuleList : public QList<Item::Module> {};

const QString moduleSearchSubDir = QLatin1String("modules");

class ModuleLoader::ProductSortByDependencies
{
public:
    ProductSortByDependencies(TopLevelProjectContext &tlp) : m_tlp(tlp)
    {
    }

    void apply()
    {
        QHash<QString, ProductContext *> productsMap;
        QList<ProductContext *> allProducts;
        for (auto projIt = m_tlp.projects.begin(); projIt != m_tlp.projects.end(); ++projIt) {
            QVector<ProductContext> &products = (*projIt)->products;
            for (auto prodIt = products.begin(); prodIt != products.end(); ++prodIt) {
                allProducts << prodIt;
                productsMap.insert(prodIt->name, prodIt);
            }
        }
        QSet<ProductContext *> allDependencies;
        foreach (auto productContext, allProducts) {
            auto &productDependencies = m_dependencyMap[productContext];
            foreach (const auto &dep, productContext->info.usedProducts) {
                if (!dep.productTypes.isEmpty())
                    continue;
                QBS_CHECK(!dep.name.isEmpty());
                ProductContext * const depProduct = productsMap.value(dep.name);
                QBS_CHECK(depProduct);
                productDependencies << depProduct;
                allDependencies << depProduct;
            }
        }
        QSet<ProductContext *> rootProducts = allProducts.toSet() - allDependencies;
        foreach (ProductContext * const rootProduct, rootProducts)
            traverse(rootProduct);
        if (m_sortedProducts.count() < allProducts.count()) {
            foreach (auto * const product, allProducts) {
                QList<ModuleLoader::ProductContext *> path;
                findCycle(product, path);
            }
        }
        QBS_CHECK(m_sortedProducts.count() == allProducts.count());
    }

    // No product at position i has dependencies to a product at position j > i.
    QList<ProductContext *> sortedProducts()
    {
        return m_sortedProducts;
    }

private:
    void traverse(ModuleLoader::ProductContext *product)
    {
        if (m_seenProducts.contains(product))
            return;
        m_seenProducts << product;
        foreach (auto dependency, m_dependencyMap.value(product))
            traverse(dependency);
        m_sortedProducts << product;
    }

    void findCycle(ModuleLoader::ProductContext *product,
                   QList<ModuleLoader::ProductContext *> &path)
    {
        if (path.contains(product)) {
            ErrorInfo error(Tr::tr("Cyclic dependencies detected."));
            foreach (const auto * const p, path)
                error.append(p->name, p->item->location());
            error.append(product->name, product->item->location());
            throw error;
        }
        path << product;
        foreach (auto * const dep, m_dependencyMap.value(product))
            findCycle(dep, path);
        path.removeLast();
    }

    TopLevelProjectContext &m_tlp;
    QHash<ProductContext *, QVector<ProductContext *>> m_dependencyMap;
    QSet<ProductContext *> m_seenProducts;
    QList<ProductContext *> m_sortedProducts;
};

class SearchPathsManager {
public:
    SearchPathsManager(ItemReader *itemReader, const QStringList &extraSearchPaths)
        : m_itemReader(itemReader)
    {
        m_itemReader->pushExtraSearchPaths(extraSearchPaths);
    }
    ~SearchPathsManager() { m_itemReader->popExtraSearchPaths(); }

private:
    ItemReader * const m_itemReader;
};

ModuleLoader::ModuleLoader(ScriptEngine *engine,
                           Logger &logger)
    : m_engine(engine)
    , m_pool(0)
    , m_logger(logger)
    , m_progressObserver(0)
    , m_reader(new ItemReader(logger))
    , m_evaluator(new Evaluator(engine, logger))
{
}

ModuleLoader::~ModuleLoader()
{
    delete m_evaluator;
    delete m_reader;
}

void ModuleLoader::setProgressObserver(ProgressObserver *progressObserver)
{
    m_progressObserver = progressObserver;
}

static void addExtraModuleSearchPath(QStringList &list, const QString &searchPath)
{
    list += FileInfo::resolvePath(searchPath, moduleSearchSubDir);
}

void ModuleLoader::setSearchPaths(const QStringList &searchPaths)
{
    m_reader->setSearchPaths(searchPaths);

    m_moduleDirListCache.clear();
    m_moduleSearchPaths.clear();
    foreach (const QString &path, searchPaths)
        addExtraModuleSearchPath(m_moduleSearchPaths, path);

    if (m_logger.traceEnabled()) {
        m_logger.qbsTrace() << "[MODLDR] module search paths:";
        foreach (const QString &path, m_moduleSearchPaths)
            m_logger.qbsTrace() << "    " << path;
    }
}

void ModuleLoader::setOldProbes(const QHash<QString, QList<ProbeConstPtr>> &oldProbes)
{
    m_oldProbes = oldProbes;
}

ModuleLoaderResult ModuleLoader::load(const SetupProjectParameters &parameters)
{
    TimedActivityLogger moduleLoaderTimer(m_logger, Tr::tr("ModuleLoader"),
                                          parameters.logElapsedTime());
    if (m_logger.traceEnabled())
        m_logger.qbsTrace() << "[MODLDR] load" << parameters.projectFilePath();
    m_parameters = parameters;
    m_productModuleCache.clear();
    m_modulePrototypeItemCache.clear();
    m_disabledItems.clear();
    m_reader->clearExtraSearchPathsStack();
    m_reader->setEnableTiming(parameters.logElapsedTime());
    m_elapsedTimeProbes = 0;

    ModuleLoaderResult result;
    m_pool = result.itemPool.data();
    m_reader->setPool(m_pool);

    const QStringList topLevelSearchPaths = parameters.finalBuildConfigurationTree()
            .value(QLatin1String("project")).toMap()
            .value(QLatin1String("qbsSearchPaths")).toStringList();
    Item *root;
    {
        SearchPathsManager searchPathsManager(m_reader, topLevelSearchPaths);
        root = m_reader->readFile(parameters.projectFilePath());
        if (!root)
            return ModuleLoaderResult();
    }

    root = wrapInProjectIfNecessary(root);

    const QString buildDirectory = TopLevelProject::deriveBuildDirectory(parameters.buildRoot(),
            TopLevelProject::deriveId(parameters.finalBuildConfigurationTree()));
    root->setProperty(QLatin1String("sourceDirectory"),
                      VariantValue::create(QFileInfo(root->file()->filePath()).absolutePath()));
    root->setProperty(QLatin1String("buildDirectory"), VariantValue::create(buildDirectory));
    root->setProperty(QLatin1String("profile"),
                      VariantValue::create(m_parameters.topLevelProfile()));
    handleTopLevelProject(&result, root, buildDirectory,
                  QSet<QString>() << QDir::cleanPath(parameters.projectFilePath()));
    result.root = root;
    result.qbsFiles = m_reader->filesRead();
    printProfilingInfo();
    return result;
}

static void handlePropertyError(const ErrorInfo &error, const SetupProjectParameters &params,
                                Logger &logger)
{
    if (params.propertyCheckingMode() == ErrorHandlingMode::Strict)
        throw error;
    logger.printWarning(error);
}

class PropertyDeclarationCheck : public ValueHandler
{
    const QSet<Item *> &m_disabledItems;
    QSet<Item *> m_handledItems;
    Item *m_parentItem;
    QString m_currentName;
    SetupProjectParameters m_params;
    Logger &m_logger;
public:
    PropertyDeclarationCheck(const QSet<Item *> &disabledItems,
                             const SetupProjectParameters &params, Logger &logger)
        : m_disabledItems(disabledItems)
        , m_parentItem(0)
        , m_params(params)
        , m_logger(logger)
    {
    }

    void operator()(Item *item)
    {
        handleItem(item);
    }

private:
    void handle(JSSourceValue *value)
    {
        if (!value->createdByPropertiesBlock()) {
            const ErrorInfo error(Tr::tr("Property '%1' is not declared.")
                                  .arg(m_currentName), value->location());
            handlePropertyError(error, m_params, m_logger);
        }
    }

    void handle(ItemValue *value)
    {
        // TODO: Remove once QBS-1030 is fixed.
        if (m_parentItem->type() == ItemType::Artifact)
            return;

        if (value->item()->type() != ItemType::ModuleInstance
                && value->item()->type() != ItemType::ModulePrefix
                && m_parentItem->file()
                && (!m_parentItem->file()->idScope()
                    || !m_parentItem->file()->idScope()->hasProperty(m_currentName))
                && !value->createdByPropertiesBlock()) {
            const ErrorInfo error(Tr::tr("Item '%1' is not declared. "
                                         "Did you forget to add a Depends item?").arg(m_currentName),
                                  value->location().isValid() ? value->location()
                                                              : m_parentItem->location());
            handlePropertyError(error, m_params, m_logger);
        } else {
            handleItem(value->item());
        }
    }

    void handleItem(Item *item)
    {
        if (m_handledItems.contains(item))
            return;
        m_handledItems.insert(item);
        if (m_disabledItems.contains(item)
                // TODO: We never checked module prototypes, apparently. Should we?
                // It's currently not possible because of e.g. things like "cpp.staticLibraries"
                // inside Artifact items...
                || item->type() == ItemType::Module

                // The Properties child of a SubProject item is not a regular item.
                || item->type() == ItemType::PropertiesInSubProject) {
            return;
        }

        Item *oldParentItem = m_parentItem;
        m_parentItem = item;
        for (Item::PropertyMap::const_iterator it = item->properties().constBegin();
                it != item->properties().constEnd(); ++it) {
            const PropertyDeclaration decl = item->propertyDeclaration(it.key());
            if (decl.isValid()) {
                if (!decl.isDeprecated())
                    continue;
                const DeprecationInfo &di = decl.deprecationInfo();
                QString message;
                bool warningOnly;
                if (di.removalVersion() <= Version::qbsVersion()) {
                    message = Tr::tr("The property '%1' can no longer be used. "
                                     "It was removed in Qbs %2.")
                            .arg(decl.name(), di.removalVersion().toString());
                    warningOnly = false;
                } else {
                    message = Tr::tr("The property '%1' is deprecated and will be removed "
                                     "in Qbs %2.").arg(decl.name(), di.removalVersion().toString());
                    warningOnly = true;
                }
                ErrorInfo error(message, it.value()->location());
                if (!di.additionalUserInfo().isEmpty())
                    error.append(di.additionalUserInfo());
                if (warningOnly)
                    m_logger.printWarning(error);
                else
                    handlePropertyError(error, m_params, m_logger);
                continue;
            }
            m_currentName = it.key();
            it.value()->apply(this);
        }
        m_parentItem = oldParentItem;
        foreach (Item *child, item->children()) {
            if (child->type () != ItemType::Export)
                handleItem(child);
        }

        // Properties that don't refer to an existing module with a matching Depends item
        // only exist in the prototype of an Export item, not in the instance.
        // Example 1 - setting a property of an unknown module: Export { abc.def: true }
        // Example 2 - setting a non-existing Export property: Export { blubb: true }
        if (item->type() == ItemType::ModuleInstance && item->prototype())
            handleItem(item->prototype());
    }

    void handle(VariantValue *) { /* only created internally - no need to check */ }
};

void ModuleLoader::handleTopLevelProject(ModuleLoaderResult *loadResult, Item *projectItem,
        const QString &buildDirectory, const QSet<QString> &referencedFilePaths)
{
    TopLevelProjectContext tlp;
    tlp.buildDirectory = buildDirectory;
    handleProject(loadResult, &tlp, projectItem, referencedFilePaths);

    foreach (ProjectContext *projectContext, tlp.projects) {
        m_reader->setExtraSearchPathsStack(projectContext->searchPathsStack);
        for (auto it = projectContext->products.begin(); it != projectContext->products.end();
             ++it) {
            try {
                setupProductDependencies(it);
            } catch (const ErrorInfo &err) {
                if (it->name.isEmpty())
                    throw err;
                handleProductError(err, it);
            }
        }
    }

    ProductSortByDependencies productSorter(tlp);
    productSorter.apply();
    foreach (ProductContext * const p, productSorter.sortedProducts()) {
        try {
            handleProduct(p);
        } catch (const ErrorInfo &err) {
            handleProductError(err, p);
        }
    }

    m_reader->clearExtraSearchPathsStack();
    PropertyDeclarationCheck check(m_disabledItems, m_parameters, m_logger);
    check(projectItem);
}

void ModuleLoader::handleProject(ModuleLoaderResult *loadResult,
        TopLevelProjectContext *topLevelProjectContext, Item *projectItem,
        const QSet<QString> &referencedFilePaths)
{
    auto *p = new ProjectContext;
    auto &projectContext = *p;
    projectContext.topLevelProject = topLevelProjectContext;
    projectContext.result = loadResult;
    ItemValuePtr itemValue = ItemValue::create(projectItem);
    projectContext.scope = Item::create(m_pool);
    projectContext.scope->setFile(projectItem->file());
    projectContext.scope->setProperty(QLatin1String("project"), itemValue);
    ProductContext dummyProductContext;
    dummyProductContext.project = &projectContext;
    dummyProductContext.moduleProperties = m_parameters.finalBuildConfigurationTree();
    projectItem->addModule(loadBaseModule(&dummyProductContext, projectItem));
    overrideItemProperties(projectItem, QLatin1String("project"),
                           m_parameters.overriddenValuesTree());
    const QString projectName = m_evaluator->stringValue(projectItem, QLatin1String("name"));
    if (!projectName.isEmpty())
        overrideItemProperties(projectItem, projectName, m_parameters.overriddenValuesTree());
    if (!checkItemCondition(projectItem)) {
        delete p;
        return;
    }
    topLevelProjectContext->projects << &projectContext;
    m_reader->pushExtraSearchPaths(readExtraSearchPaths(projectItem)
                                   << projectItem->file()->dirPath());
    projectContext.searchPathsStack = m_reader->extraSearchPathsStack();
    projectContext.item = projectItem;

    const QString minVersionStr
            = m_evaluator->stringValue(projectItem, QLatin1String("minimumQbsVersion"),
                                       QLatin1String("1.3.0"));
    const Version minVersion = Version::fromString(minVersionStr);
    if (!minVersion.isValid()) {
        throw ErrorInfo(Tr::tr("The value '%1' of Project.minimumQbsVersion "
                "is not a valid version string.").arg(minVersionStr), projectItem->location());
    }
    if (!m_qbsVersion.isValid())
        m_qbsVersion = Version::fromString(QLatin1String(QBS_VERSION));
    if (m_qbsVersion < minVersion) {
        throw ErrorInfo(Tr::tr("The project requires at least qbs version %1, but "
                               "this is qbs version %2.").arg(minVersion.toString(),
                                                              m_qbsVersion.toString()));
    }

    foreach (Item *child, projectItem->children()) {
        child->setScope(projectContext.scope);
        if (child->type() == ItemType::Product) {
            foreach (Item * const additionalProductItem,
                     multiplexProductItem(&dummyProductContext, child)) {
                Item::addChild(projectItem, additionalProductItem);
            }
        }
    }

    foreach (Item *child, projectItem->children()) {
        switch (child->type()) {
        case ItemType::Product:
            prepareProduct(&projectContext, child);
            break;
        case ItemType::SubProject:
            handleSubProject(&projectContext, child, referencedFilePaths);
            break;
        case ItemType::Project:
            copyProperties(projectItem, child);
            handleProject(loadResult, topLevelProjectContext, child, referencedFilePaths);
            break;
        default:
            break;
        }
    }

    const QStringList refs = m_evaluator->stringListValue(projectItem, QLatin1String("references"));
    const CodeLocation referencingLocation
            = projectItem->property(QLatin1String("references"))->location();
    QList<Item *> additionalProjectChildren;
    foreach (const QString &filePath, refs) {
        try {
            additionalProjectChildren << loadReferencedFile(filePath, referencingLocation,
                    referencedFilePaths, dummyProductContext);
        } catch (const ErrorInfo &error) {
            if (m_parameters.productErrorMode() == ErrorHandlingMode::Strict)
                throw;
            m_logger.printWarning(error);
        }
    }
    foreach (Item * const subItem, additionalProjectChildren) {
        Item::addChild(projectContext.item, subItem);
        switch (subItem->type()) {
        case ItemType::Product:
            prepareProduct(&projectContext, subItem);
            break;
        case ItemType::Project:
            copyProperties(projectItem, subItem);
            handleProject(loadResult, topLevelProjectContext, subItem,
                          QSet<QString>(referencedFilePaths) << subItem->file()->filePath());
            break;
        default:
            break;
        }
    }
    m_reader->popExtraSearchPaths();
}

QList<Item *> ModuleLoader::multiplexProductItem(ProductContext *dummyContext, Item *productItem)
{
    // Temporarily attach the qbs module here, in case we need to access one of its properties
    // to evaluate the profiles property.
    const QString qbsKey = QLatin1String("qbs");
    ValuePtr qbsValue = productItem->property(qbsKey); // Retrieve now to restore later.
    if (qbsValue)
        qbsValue = qbsValue->clone();
    productItem->addModule(loadBaseModule(dummyContext, productItem));

    // Overriding the product item properties must be done here already, because otherwise
    // the "profiles" property would not be overridable.
    QString productName = m_evaluator->stringValue(productItem, QLatin1String("name"));
    if (productName.isEmpty()) {
        productName = FileInfo::completeBaseName(productItem->file()->filePath());
        productItem->setProperty(QLatin1String("name"), VariantValue::create(productName));
    }
    overrideItemProperties(productItem, productName, m_parameters.overriddenValuesTree());

    const QString profilesKey = QLatin1String("profiles");
    const ValueConstPtr profilesValue = productItem->property(profilesKey);
    QBS_CHECK(profilesValue); // Default value set in BuiltinDeclarations.
    const QStringList profileNames = m_evaluator->stringListValue(productItem, profilesKey);
    if (profileNames.isEmpty()) {
        throw ErrorInfo(Tr::tr("The 'profiles' property cannot be an empty list."),
                        profilesValue->location());
    }
    foreach (const QString &profileName, profileNames) {
        if (profileNames.count(profileName) > 1) {
            throw ErrorInfo(Tr::tr("The profile '%1' appears in the 'profiles' list twice, "
                    "which is not allowed.").arg(profileName), profilesValue->location());
        }
    }

    // "Unload" the qbs module again.
    if (qbsValue)
        productItem->setProperty(qbsKey, qbsValue);
    else
        productItem->removeProperty(qbsKey);
    productItem->removeModules();

    QList<Item *> additionalProductItems;
    const QString profileKey = QLatin1String("profile");
    productItem->setProperty(profileKey, VariantValue::create(profileNames.first()));
    Settings settings(m_parameters.settingsDirectory());
    for (int i = 0; i < profileNames.count(); ++i) {
        Profile profile(profileNames.at(i), &settings);
        if (!profile.exists()) {
            throw ErrorInfo(Tr::tr("The profile '%1' does not exist.").arg(profile.name()),
                            productItem->location()); // TODO: profilesValue->location() is invalid, why?
        }
        if (i == 0)
            continue; // We use the original item for the first profile.
        Item * const cloned = productItem->clone();
        cloned->setProperty(profileKey, VariantValue::create(profileNames.at(i)));
        additionalProductItems << cloned;
    }
    return additionalProductItems;
}

void ModuleLoader::prepareProduct(ProjectContext *projectContext, Item *productItem)
{
    checkCancelation();
    if (m_logger.traceEnabled())
        m_logger.qbsTrace() << "[MODLDR] prepareProduct " << productItem->file()->filePath();

    ProductContext productContext;
    productContext.name = m_evaluator->stringValue(productItem, QLatin1String("name"));
    QBS_CHECK(!productContext.name.isEmpty());
    bool profilePropertySet;
    productContext.profileName = m_evaluator->stringValue(productItem, QLatin1String("profile"),
                                                         QString(), &profilePropertySet);
    QBS_CHECK(profilePropertySet);
    const QVariantMap::ConstIterator it
            = projectContext->result->profileConfigs.find(productContext.profileName);
    if (it == projectContext->result->profileConfigs.constEnd()) {
        const QVariantMap buildConfig = SetupProjectParameters::expandedBuildConfiguration(
                    m_parameters.settingsDirectory(), productContext.profileName,
                    m_parameters.configurationName());
        productContext.moduleProperties = SetupProjectParameters::finalBuildConfigurationTree(
                    buildConfig, m_parameters.overriddenValues(), m_parameters.buildRoot());
        projectContext->result->profileConfigs.insert(productContext.profileName,
                                                      productContext.moduleProperties);
    } else {
        productContext.moduleProperties = it.value().toMap();
    }
    productContext.item = productItem;
    productContext.project = projectContext;
    initProductProperties(productContext);

    ItemValuePtr itemValue = ItemValue::create(productItem);
    productContext.scope = Item::create(m_pool);
    productContext.scope->setProperty(QLatin1String("product"), itemValue);
    productContext.scope->setFile(productItem->file());
    productContext.scope->setScope(productContext.project->scope);

    mergeExportItems(productContext);

    setScopeForDescendants(productItem, productContext.scope);

    projectContext->products << productContext;
}

void ModuleLoader::setupProductDependencies(ProductContext *productContext)
{
    checkCancelation();
    Item *item = productContext->item;
    if (m_logger.traceEnabled())
        m_logger.qbsTrace() << "[MODLDR] handleProduct " << item->file()->filePath();

    QStringList extraSearchPaths = readExtraSearchPaths(item);
    Settings settings(m_parameters.settingsDirectory());
    const QStringList prefsSearchPaths
            = Preferences(&settings, productContext->profileName).searchPaths();
    foreach (const QString &p, prefsSearchPaths) {
        if (!m_moduleSearchPaths.contains(p) && FileInfo(p).exists())
            extraSearchPaths << p;
    }
    SearchPathsManager searchPathsManager(m_reader, extraSearchPaths);

    DependsContext dependsContext;
    dependsContext.product = productContext;
    dependsContext.productDependencies = &productContext->info.usedProducts;
    resolveDependencies(&dependsContext, item);
    addTransitiveDependencies(productContext);
    productContext->project->result->productInfos.insert(item, productContext->info);
}

// Non-dependencies first.
static void createSortedModuleList(const Item::Module &parentModule, QVector<Item::Module> &modules)
{
    if (modules.contains(parentModule))
        return;
    foreach (const Item::Module &dep, parentModule.item->modules())
        createSortedModuleList(dep, modules);
    modules << parentModule;
    return;
}

template<typename T> bool insertIntoSet(std::set<T> &set, const T &value)
{
    const auto insertionResult = set.insert(value);
    return insertionResult.second;
}

void ModuleLoader::setupReverseModuleDependencies(const Item::Module &module,
                                                  ModuleDependencies &deps,
                                                  QualifiedIdSet &seenModules)
{
    if (!insertIntoSet(seenModules, module.name))
        return;
    const Item::Modules &modules = module.item->modules();
    for (auto it = modules.begin(); it != modules.end(); ++it) {
        deps[it->name].insert(module.name);
        setupReverseModuleDependencies(*it, deps, seenModules);
    }
}

ModuleLoader::ModuleDependencies ModuleLoader::setupReverseModuleDependencies(const Item *product)
{
    ModuleDependencies deps;
    QualifiedIdSet seenModules;
    const Item::Modules &modules = product->modules();
    for (auto it = modules.begin(); it != modules.end(); ++it)
        setupReverseModuleDependencies(*it, deps, seenModules);
    return deps;
}

void ModuleLoader::handleProduct(ModuleLoader::ProductContext *productContext)
{
    if (productContext->info.hasError)
        return;

    Item * const item = productContext->item;

    Item::Modules mergedModules;
    foreach (const Item::Module &module, item->modules()) {
        Item::Module mergedModule = module;
        ModuleMerger(m_logger, item, mergedModule).start();
        mergedModules << mergedModule;
    }
    item->setModules(mergedModules);

    // Must happen after all modules have been merged, so needs to be a second loop.
    QVector<Item::Module> sortedModules;
    foreach (const Item::Module &module, item->modules())
        createSortedModuleList(module, sortedModules);
    QBS_CHECK(sortedModules.count() == item->modules().count());

    foreach (const Item::Module &module, sortedModules) {
        if (!module.item->isPresentModule())
            continue;
        try {
            resolveProbes(productContext, module.item);
            if (module.versionRange.minimum.isValid()
                    || module.versionRange.maximum.isValid()) {
                if (module.versionRange.maximum.isValid()
                        && module.versionRange.minimum >= module.versionRange.maximum) {
                    throw ErrorInfo(Tr::tr("Impossible version constraint [%1,%2) set for module "
                                           "'%3'").arg(module.versionRange.minimum.toString(),
                                                       module.versionRange.maximum.toString(),
                                                       module.name.toString()));
                }
                const Version moduleVersion = Version::fromString(
                            m_evaluator->stringValue(module.item, QLatin1String("version")));
                if (moduleVersion < module.versionRange.minimum) {
                    throw ErrorInfo(Tr::tr("Module '%1' has version %2, but it needs to be "
                            "at least %3.").arg(module.name.toString(),
                                                moduleVersion.toString(),
                                                module.versionRange.minimum.toString()));
                }
                if (module.versionRange.maximum.isValid()
                        && moduleVersion >= module.versionRange.maximum) {
                    throw ErrorInfo(Tr::tr("Module '%1' has version %2, but it needs to be "
                            "lower than %3.").arg(module.name.toString(),
                                               moduleVersion.toString(),
                                               module.versionRange.maximum.toString()));
                }
            }
        } catch (const ErrorInfo &error) {
            handleModuleSetupError(productContext, module, error);
        }
    }

    resolveProbes(productContext, item);

    // Module validation must happen in an extra pass, after all Probes have been resolved.
    EvalCacheEnabler cacheEnabler(m_evaluator);
    foreach (const Item::Module &module, sortedModules) {
        if (!module.item->isPresentModule() || module.item->delayedError().hasError())
            continue;
        try {
            m_evaluator->boolValue(module.item, QLatin1String("validate"));
        } catch (const ErrorInfo &error) {
            handleModuleSetupError(productContext, module, error);
        }
    }

    if (!checkItemCondition(item)) {
        Item * const productModule = m_productModuleCache.value(productContext->name);
        if (productModule && productModule->isPresentModule())
            createNonPresentModule(productContext->name, QLatin1String("disabled"), productModule);
    }

    copyGroupsFromModulesToProduct(*productContext);

    ModuleDependencies reverseModuleDeps;
    foreach (Item *child, item->children()) {
        if (child->type() == ItemType::Group) {
            if (reverseModuleDeps.isEmpty())
                reverseModuleDeps = setupReverseModuleDependencies(item);
            handleGroup(child, reverseModuleDeps);
        }
    }
    productContext->project->result->productInfos.insert(item, productContext->info);
}

void ModuleLoader::handleModuleSetupError(ModuleLoader::ProductContext *productContext,
                                          const Item::Module &module, const ErrorInfo &error)
{
    if (module.required) {
        try {
            handleProductError(error, productContext);
        } catch (const ErrorInfo &) {
            // Error will be thrown for enabled products only
            module.item->setDelayedError(error);
        }
    } else {
        createNonPresentModule(module.name.toString(), QLatin1String("failed validation"),
                               module.item);
    }
}

void ModuleLoader::initProductProperties(const ProductContext &product)
{
    QString buildDir = ResolvedProduct::deriveBuildDirectoryName(product.name, product.profileName);
    buildDir = FileInfo::resolvePath(product.project->topLevelProject->buildDirectory, buildDir);
    product.item->setProperty(QLatin1String("buildDirectory"), VariantValue::create(buildDir));
    const QString sourceDir = QFileInfo(product.item->file()->filePath()).absolutePath();
    product.item->setProperty(QLatin1String("sourceDirectory"), VariantValue::create(sourceDir));
}

void ModuleLoader::handleSubProject(ModuleLoader::ProjectContext *projectContext, Item *projectItem,
        const QSet<QString> &referencedFilePaths)
{
    if (m_logger.traceEnabled())
        m_logger.qbsTrace() << "[MODLDR] handleSubProject " << projectItem->file()->filePath();

    Item * const propertiesItem = projectItem->child(ItemType::PropertiesInSubProject);
    bool subProjectEnabled = true;
    if (propertiesItem) {
        propertiesItem->setScope(projectItem);
        subProjectEnabled = checkItemCondition(propertiesItem);
    }
    if (!subProjectEnabled)
        return;

    Item *loadedItem;
    QString subProjectFilePath;
    try {
        const QString projectFileDirPath = FileInfo::path(projectItem->file()->filePath());
        const QString relativeFilePath
                = m_evaluator->stringValue(projectItem, QLatin1String("filePath"));
        subProjectFilePath = FileInfo::resolvePath(projectFileDirPath, relativeFilePath);
        if (referencedFilePaths.contains(subProjectFilePath))
            throw ErrorInfo(Tr::tr("Cycle detected while loading subproject file '%1'.")
                            .arg(relativeFilePath), projectItem->location());
        loadedItem = m_reader->readFile(subProjectFilePath);
    } catch (const ErrorInfo &error) {
        if (m_parameters.productErrorMode() == ErrorHandlingMode::Strict)
            throw;
        m_logger.printWarning(error);
        return;
    }

    loadedItem = wrapInProjectIfNecessary(loadedItem);
    const bool inheritProperties
            = m_evaluator->boolValue(projectItem, QLatin1String("inheritProperties"), true);

    if (inheritProperties)
        copyProperties(projectItem->parent(), loadedItem);
    if (propertiesItem) {
        const Item::PropertyMap &overriddenProperties = propertiesItem->properties();
        for (Item::PropertyMap::ConstIterator it = overriddenProperties.constBegin();
             it != overriddenProperties.constEnd(); ++it) {
            loadedItem->setProperty(it.key(), overriddenProperties.value(it.key()));
        }
    }

    Item::addChild(projectItem, loadedItem);
    projectItem->setScope(projectContext->scope);
    handleProject(projectContext->result, projectContext->topLevelProject, loadedItem,
                  QSet<QString>(referencedFilePaths) << subProjectFilePath);
}

QList<Item *> ModuleLoader::loadReferencedFile(const QString &relativePath,
                                               const CodeLocation &referencingLocation,
                                               const QSet<QString> &referencedFilePaths,
                                               ModuleLoader::ProductContext &dummyContext)
{
    QString absReferencePath = FileInfo::resolvePath(FileInfo::path(referencingLocation.filePath()),
                                                     relativePath);
    if (FileInfo(absReferencePath).isDir()) {
        QString qbsFilePath;
        QDirIterator dit(absReferencePath, QStringList(QLatin1String("*.qbs")));
        while (dit.hasNext()) {
            if (!qbsFilePath.isEmpty()) {
                throw ErrorInfo(Tr::tr("Referenced directory '%1' contains more than one "
                                       "qbs file.").arg(absReferencePath), referencingLocation);
            }
            qbsFilePath = dit.next();
        }
        if (qbsFilePath.isEmpty()) {
            throw ErrorInfo(Tr::tr("Referenced directory '%1' does not contain a qbs file.")
                            .arg(absReferencePath), referencingLocation);
        }
        absReferencePath = qbsFilePath;
    }
    if (referencedFilePaths.contains(absReferencePath))
        throw ErrorInfo(Tr::tr("Cycle detected while referencing file '%1'.").arg(relativePath),
                        referencingLocation);
    Item * const subItem = m_reader->readFile(absReferencePath);
    if (subItem->type() != ItemType::Project && subItem->type() != ItemType::Product) {
        ErrorInfo error(Tr::tr("Item type should be 'Product' or 'Project', but is '%1'.")
                        .arg(subItem->typeName()));
        error.append(Tr::tr("Item is defined here."), subItem->location());
        error.append(Tr::tr("File is referenced here."), referencingLocation);
        throw  error;
    }
    subItem->setScope(dummyContext.project->scope);
    subItem->setParent(dummyContext.project->item);
    QList<Item *> loadedItems;
    loadedItems << subItem;
    if (subItem->type() == ItemType::Product)
        loadedItems << multiplexProductItem(&dummyContext, subItem);
    return loadedItems;
}

void ModuleLoader::handleGroup(Item *groupItem, const ModuleDependencies &reverseDepencencies)
{
    checkCancelation();
    propagateModulesFromParent(groupItem, reverseDepencencies);
    checkItemCondition(groupItem);
    foreach (Item * const child, groupItem->children()) {
        if (child->type() == ItemType::Group)
            handleGroup(child, reverseDepencencies);
    }
}

void ModuleLoader::handleAllPropertyOptionsItems(Item *item)
{
    foreach (Item * const child, item->children()) {
        if (child->type() == ItemType::PropertyOptions)
            handlePropertyOptions(child);
    }
}

void ModuleLoader::handlePropertyOptions(Item *optionsItem)
{
    const QString name = m_evaluator->stringValue(optionsItem, QLatin1String("name"));
    if (name.isEmpty()) {
        throw ErrorInfo(Tr::tr("PropertyOptions item needs a name property"),
                        optionsItem->location());
    }
    if (!optionsItem->parent()->hasProperty(name)) {
        throw ErrorInfo(Tr::tr("PropertyOptions item refers to non-existing property '%1'")
                        .arg(name), optionsItem->location());
    }
    const QString description = m_evaluator->stringValue(optionsItem, QLatin1String("description"));
    const auto removalVersion = Version::fromString(m_evaluator->stringValue(optionsItem,
            QLatin1String("removalVersion")));
    PropertyDeclaration decl = optionsItem->parent()->propertyDeclaration(name);
    if (!decl.isValid()) {
        decl.setName(name);
        decl.setType(PropertyDeclaration::Variant);
    }
    decl.setDescription(description);
    if (removalVersion.isValid()) {
        DeprecationInfo di(removalVersion, description);
        decl.setDeprecationInfo(di);
    }
    optionsItem->parent()->setPropertyDeclaration(name, decl);
}

static void mergeProperty(Item *dst, const QString &name, const ValuePtr &value)
{
    if (value->type() == Value::ItemValueType) {
        Item *valueItem = value.staticCast<ItemValue>()->item();
        Item *subItem = dst->itemProperty(name, true)->item();
        for (QMap<QString, ValuePtr>::const_iterator it = valueItem->properties().constBegin();
                it != valueItem->properties().constEnd(); ++it)
            mergeProperty(subItem, it.key(), it.value());
    } else {
        // If the property already exists set up the base value.
        if (value->type() == Value::JSSourceValueType) {
            const ValuePtr baseValue = dst->property(name);
            if (baseValue) {
                QBS_CHECK(baseValue->type() == Value::JSSourceValueType);
                const JSSourceValuePtr jsBaseValue = baseValue->clone().staticCast<JSSourceValue>();
                JSSourceValue *jsValue = static_cast<JSSourceValue *>(value.data());
                jsValue->setBaseValue(jsBaseValue);
            }
        }
        dst->setProperty(name, value);
    }
}

bool ModuleLoader::checkExportItemCondition(Item *exportItem, const ProductContext &productContext)
{
    class ScopeHandler {
    public:
        ScopeHandler(Item *exportItem, const ProductContext &productContext, Item **cachedScopeItem)
            : m_exportItem(exportItem)
        {
            if (!*cachedScopeItem)
                *cachedScopeItem = Item::create(exportItem->pool());
            Item * const scope = *cachedScopeItem;
            QBS_CHECK(productContext.item->file());
            scope->setFile(productContext.item->file());
            scope->setScope(productContext.item);
            productContext.project->scope->copyProperty(QLatin1String("project"), scope);
            productContext.scope->copyProperty(QLatin1String("product"), scope);
            QBS_CHECK(!exportItem->scope());
            exportItem->setScope(scope);
        }
        ~ScopeHandler() { m_exportItem->setScope(nullptr); }

    private:
        Item * const m_exportItem;
    } scopeHandler(exportItem, productContext, &m_tempScopeItem);
    return checkItemCondition(exportItem);
}

ProbeConstPtr ModuleLoader::findOldProbe(const QString &product,
                                         bool condition,
                                         const QVariantMap &initialProperties,
                                         const QString &sourceCode) const
{
    if (m_parameters.forceProbeExecution())
        return ProbeConstPtr();
    foreach (const ProbeConstPtr &oldProbe, m_oldProbes.value(product)) {
        if (oldProbe->condition() != condition)
            continue;
        if (oldProbe->configureScript() != sourceCode)
            continue;
        if (oldProbe->initialProperties() != initialProperties)
            continue;
        return oldProbe;
    }

    return ProbeConstPtr();
}

ProbeConstPtr ModuleLoader::findCurrentProbe(const CodeLocation &location, bool condition,
                                             const QVariantMap &initialProperties) const
{
    const QList<ProbeConstPtr> cachedProbes = m_currentProbes.value(location);
    foreach (const ProbeConstPtr &p, cachedProbes) {
        if (p->condition() == condition && p->initialProperties() == initialProperties)
            return p;
    }
    return ProbeConstPtr();
}

void ModuleLoader::printProfilingInfo()
{
    if (!m_parameters.logElapsedTime())
        return;
    m_logger.qbsLog(LoggerInfo, true) << "\t"
                                      << Tr::tr("Project file loading and parsing took %1.")
                                         .arg(elapsedTimeString(m_reader->elapsedTime()));
    m_logger.qbsLog(LoggerInfo, true) << "\t"
                                      << Tr::tr("Running Probes took %1.")
                                         .arg(elapsedTimeString(m_elapsedTimeProbes));
}

void ModuleLoader::mergeExportItems(const ProductContext &productContext)
{
    QVector<Item *> exportItems;
    QList<Item *> children = productContext.item->children();
    for (int i = 0; i < children.count();) {
        Item * const child = children.at(i);
        if (child->type() == ItemType::Export) {
            exportItems << child;
            children.removeAt(i);
        } else {
            ++i;
        }
    }

    // Note that we do not return if there are no Export items: The "merged" item becomes the
    // "product module", which always needs to exist, regardless of whether the product sources
    // actually contain an Export item or not.
    if (!exportItems.isEmpty())
        productContext.item->setChildren(children);

    Item *merged = Item::create(productContext.item->pool(), ItemType::Export);
    QSet<FileContextConstPtr> filesWithExportItem;
    foreach (Item *exportItem, exportItems) {
        checkCancelation();
        if (Q_UNLIKELY(filesWithExportItem.contains(exportItem->file())))
            throw ErrorInfo(Tr::tr("Multiple Export items in one product are prohibited."),
                        exportItem->location());
        if (!checkExportItemCondition(exportItem, productContext))
            continue;
        filesWithExportItem += exportItem->file();
        foreach (Item *child, exportItem->children())
            Item::addChild(merged, child);
        const Item::PropertyDeclarationMap &decls = exportItem->propertyDeclarations();
        for (auto it = decls.constBegin(); it != decls.constEnd(); ++it) {
            const PropertyDeclaration &newDecl = it.value();
            const PropertyDeclaration &existingDecl = merged->propertyDeclaration(it.key());
            if (existingDecl.isValid() && existingDecl.type() != newDecl.type()) {
                ErrorInfo error(Tr::tr("Export item in inherited item redeclares property "
                        "'%1' with different type.").arg(it.key()), exportItem->location());
                handlePropertyError(error, m_parameters, m_logger);
            }
            merged->setPropertyDeclaration(newDecl.name(), newDecl);
        }
        for (QMap<QString, ValuePtr>::const_iterator it = exportItem->properties().constBegin();
                it != exportItem->properties().constEnd(); ++it) {
            mergeProperty(merged, it.key(), it.value());
        }
    }
    merged->setFile(exportItems.isEmpty()
            ? productContext.item->file() : exportItems.last()->file());
    merged->setLocation(exportItems.isEmpty()
            ? productContext.item->location() : exportItems.last()->location());
    Item::addChild(productContext.item, merged);
    merged->setupForBuiltinType(m_logger);
    ProductModuleInfo &pmi
            = productContext.project->topLevelProject->productModules[productContext.name];
    pmi.exportItem = merged;
}

bool ModuleLoader::isSomeModulePropertySet(const Item *item)
{
    for (auto it = item->properties().cbegin(); it != item->properties().cend(); ++it) {
        switch (it.value()->type()) {
        case Value::JSSourceValueType:
            if (item->type() == ItemType::ModuleInstance) {
                if (m_logger.traceEnabled()) {
                    m_logger.qbsTrace() << "[LDR] scope adaptation for group module items "
                                           "necessary because of property " << it.key();
                }
                return true;
            }
            break;
        case Value::ItemValueType:
            if (isSomeModulePropertySet(it.value().staticCast<ItemValue>()->item()))
                return true;
            break;
        default:
            break;
        }
    }
    return false;
}

void ModuleLoader::propagateModulesFromParent(Item *groupItem,
                                              const ModuleDependencies &reverseDepencencies)
{
    QBS_CHECK(groupItem->type() == ItemType::Group);
    QHash<QualifiedId, Item *> moduleInstancesForGroup;

    // Step 1: Instantiate the product's modules for the group.
    for (Item::Modules::const_iterator it = groupItem->parent()->modules().constBegin();
         it != groupItem->parent()->modules().constEnd(); ++it)
    {
        Item::Module m = *it;
        Item *targetItem = moduleInstanceItem(groupItem, m.name);
        targetItem->setPrototype(m.item);
        targetItem->setType(ItemType::ModuleInstance);

        Item * const moduleScope = Item::create(targetItem->pool(), ItemType::Scope);
        moduleScope->setFile(groupItem->file());
        moduleScope->setProperties(m.item->scope()->properties()); // "project", "product", ids
        moduleScope->setScope(groupItem);
        targetItem->setScope(moduleScope);

        targetItem->setFile(m.item->file());

        // "parent" should point to the group/artifact parent
        targetItem->setParent(groupItem->parent());

        targetItem->setOuterItem(m.item);

        m.item = targetItem;
        groupItem->addModule(m);
        moduleInstancesForGroup.insert(m.name, targetItem);
    }

    // Step 2: Make the inter-module references point to the instances created in step 1.
    for (auto it = groupItem->modules().cbegin(); it != groupItem->modules().cend(); ++it) {
        Item::Modules adaptedModules;
        const Item::Modules &oldModules = it->item->prototype()->modules();
        for (auto depIt = oldModules.begin(); depIt != oldModules.end(); ++depIt) {
            Item::Module depMod = *depIt;
            depMod.item = moduleInstancesForGroup.value(depIt->name);
            adaptedModules << depMod;
            if (depMod.name.first() == it->name.first())
                continue;
            const ItemValuePtr &modulePrefix = groupItem->itemProperty(depMod.name.first());
            QBS_CHECK(modulePrefix);
            it->item->setProperty(depMod.name.first(), modulePrefix);
        }
        it->item->setModules(adaptedModules);
    }

    if (!isSomeModulePropertySet(groupItem))
        return;

    // Step 3: Adapt defining items in values. This is potentially necessary if module properties
    //         get assigned on the group level.
    const Item::Modules &groupModules = groupItem->modules();
    for (auto modIt = groupModules.begin(); modIt != groupModules.end(); ++modIt) {
        const QualifiedIdSet &dependents = reverseDepencencies.value(modIt->name);
        Item::Modules dependentModules;
        dependentModules.reserve(int(dependents.size()));
        for (auto depIt = dependents.begin(); depIt != dependents.end(); ++depIt) {
            Item * const itemOfDependent = moduleInstancesForGroup.value(*depIt);
            QBS_CHECK(itemOfDependent);
            Item::Module depMod;
            depMod.name = *depIt;
            depMod.item = itemOfDependent;
            dependentModules << depMod;
        }
        adjustDefiningItemsInGroupModuleInstances(*modIt, dependentModules);
    }
}

void ModuleLoader::adjustDefiningItemsInGroupModuleInstances(const Item::Module &module,
        const Item::Modules &dependentModules)
{
    // There are three cases:
    //     a) The defining item is the "main" module instance, i.e. the one instantiated in the
    //        product directly (or a parent group).
    //     b) The defining item refers to the module prototype (or the replacement of it
    //        created in the module merger [for products] or in this function [for parent groups]).
    //     c) The defining item is a different instance of the module, i.e. it was instantiated
    //        in some other module.

    QHash<Item *, Item *> definingItemReplacements;

    Item *modulePrototype = module.item->prototype();
    while (modulePrototype->prototype())
        modulePrototype = modulePrototype->prototype();

    // TODO: Why are there module instances whose top-level prototype is of type ModuleInstance?
    // QBS_CHECK(modulePrototype->type() == ItemType::Module);

    const Item::PropertyDeclarationMap &propDecls = modulePrototype->propertyDeclarations();
    for (const auto &decl : propDecls) {
        const QString &propName = decl.name();

        // Module properties assigned in the group are not relevant here, as nothing
        // gets inherited in that case. In particular, setting a list property
        // overwrites the value from the product's (or parent group's) instance completely,
        // rather than appending to it (concatenation happens via outer.concat()).
        ValueConstPtr propValue = module.item->properties().value(propName);
        if (propValue)
            continue;

        // Find the nearest prototype instance that has the value assigned.
        // The result is either an instance of a parent group (or the parent group's
        // parent group and so on) or the instance of the product or the module prototype.
        // In the latter case, we don't have to do anything.
        const Item *instanceWithProperty = module.item;
        int prototypeChainLen = 0;
        do {
            instanceWithProperty = instanceWithProperty->prototype();
            QBS_CHECK(instanceWithProperty);
            ++prototypeChainLen;
            propValue = instanceWithProperty->properties().value(propName);
        } while (!propValue);
        QBS_CHECK(propValue);

        if (propValue->type() != Value::JSSourceValueType)
            continue;

        bool hasDefiningItem = false;
        for (ValueConstPtr v = propValue; v && !hasDefiningItem; v = v->next())
            hasDefiningItem = v->definingItem();
        if (!hasDefiningItem) {
            QBS_CHECK(decl.isScalar() || instanceWithProperty == modulePrototype);
            continue;
        }

        const ValuePtr clonedValue = propValue->clone();
        for (ValuePtr v = clonedValue; v; v = v->next()) {
            QBS_CHECK(v->definingItem());

            Item *& replacement = definingItemReplacements[v->definingItem()];
            static const QString caseA = QLatin1String("__group_case_a");
            if (v->definingItem() == instanceWithProperty
                    || v->definingItem()->variantProperty(caseA)) {
                // Case a)
                // For values whose defining item is the product's (or parent group's) instance,
                // we take its scope and replace references to module instances with those from the
                // group's instance. This handles cases like the following:
                // Product {
                //    name: "theProduct"
                //    aModule.listProp: [name, otherModule.stringProp]
                //    Group { name: "theGroup"; otherModule.stringProp: name }
                //    ...
                // }
                // In the above example, aModule.listProp is set to ["theProduct", "theGroup"]
                // (plus potential values from the prototype and other module instances,
                // which are different Value objects in the "next chain").
                if (!replacement) {
                    replacement = Item::create(v->definingItem()->pool());
                    Item * const scope = Item::create(v->definingItem()->pool(), ItemType::Scope);
                    scope->setProperties(module.item->scope()->properties());
                    Item * const scopeScope
                            = Item::create(v->definingItem()->pool(), ItemType::Scope);
                    scopeScope->setProperties(v->definingItem()->scope()->scope()->properties());
                    scope->setScope(scopeScope);
                    replacement->setScope(scope);
                    const Item::PropertyMap &groupScopeProperties
                            = module.item->scope()->scope()->properties();
                    for (auto propIt = groupScopeProperties.begin();
                         propIt != groupScopeProperties.end(); ++propIt) {
                        if (propIt.value()->type() == Value::ItemValueType)
                            scopeScope->setProperty(propIt.key(), propIt.value());
                    }
                }
                replacement->setPropertyDeclaration(propName, decl);
                replacement->setProperty(propName, v);
                replacement->setProperty(caseA, VariantValue::create(QVariant()));
            }  else if (v->definingItem()->type() == ItemType::Module) {
                // Case b)
                // For values whose defining item is the module prototype, we change the scope to
                // the group's instance, analogous to what we do in
                // ModuleMerger::appendPrototypeValueToNextChain().
                QBS_CHECK(!decl.isScalar());
                QBS_CHECK(!v->next());
                Item *& replacement = definingItemReplacements[v->definingItem()];
                if (!replacement) {
                    replacement = Item::create(v->definingItem()->pool(),
                                                        ItemType::Module);
                    replacement->setScope(module.item);
                }
                QBS_CHECK(!replacement->hasOwnProperty(caseA));
                if (m_logger.traceEnabled()) {
                    m_logger.qbsTrace() << "[LDR] replacing defining item for prototype; module is "
                            << module.name.toString() << module.item
                            << ", property is " << propName
                            << ", old defining item was " << v->definingItem()
                            << " with scope" << v->definingItem()->scope()
                            << ", new defining item is" << replacement
                            << " with scope" << replacement->scope()
                            << ", value source code is "
                            << v.staticCast<JSSourceValue>()->sourceCode().toString();
                }
                replacement->setPropertyDeclaration(propName, decl);
                replacement->setProperty(propName, v);
            } else {
                // Look for instance scopes of other module instances in defining items and
                // replace the affected values.
                // This is case c) as introduced above. See ModuleMerger::replaceItemInScopes()
                // for a detailed explanation.

                QBS_CHECK(v->definingItem()->scope() && v->definingItem()->scope()->scope());
                bool found = false;
                for (auto depIt = dependentModules.cbegin(); depIt != dependentModules.cend();
                     ++depIt) {
                    const Item::Module &depMod = *depIt;
                    const Item *depModPrototype = depMod.item->prototype();
                    for (int i = 1; i < prototypeChainLen; ++i)
                        depModPrototype = depModPrototype->prototype();
                    if (v->definingItem()->scope()->scope() != depModPrototype)
                        continue;

                    found = true;
                    Item *& replacement = definingItemReplacements[v->definingItem()];
                    if (!replacement) {
                        replacement = Item::create(v->definingItem()->pool());
                        replacement->setProperties(v->definingItem()->properties());
                        foreach (const auto &decl, v->definingItem()->propertyDeclarations())
                            replacement->setPropertyDeclaration(decl.name(), decl);
                        replacement->setPrototype(v->definingItem()->prototype());
                        replacement->setScope(Item::create(v->definingItem()->pool()));
                        replacement->scope()->setScope(depMod.item);
                    }
                    QBS_CHECK(!replacement->hasOwnProperty(caseA));
                    if (m_logger.traceEnabled()) {
                        m_logger.qbsTrace() << "[LDR] reset instance scope of module "
                                << depMod.name.toString() << " in property "
                                << propName << " of module " << module.name;
                    }
                }
                QBS_CHECK(found);
            }
            QBS_CHECK(replacement);
            v->setDefiningItem(replacement);
        }
        module.item->setProperty(propName, clonedValue);
    }
}

void ModuleLoader::resolveDependencies(DependsContext *dependsContext, Item *item)
{
    const Item::Module baseModule = loadBaseModule(dependsContext->product, item);
    // Resolve all Depends items.
    ItemModuleList loadedModules;
    ProductDependencyResults productDependencies;
    foreach (Item *child, item->children())
        if (child->type() == ItemType::Depends)
            resolveDependsItem(dependsContext, item, child, &loadedModules, &productDependencies);

    item->addModule(baseModule);
    foreach (const Item::Module &module, loadedModules)
        item->addModule(module);

    dependsContext->productDependencies->append(productDependencies);
}

class RequiredChainManager
{
public:
    RequiredChainManager(QStack<bool> &requiredChain, bool required)
        : m_requiredChain(requiredChain)
    {
        m_requiredChain.push(required);
    }

    ~RequiredChainManager() { m_requiredChain.pop(); }

private:
    QStack<bool> &m_requiredChain;
};

void ModuleLoader::resolveDependsItem(DependsContext *dependsContext, Item *parentItem,
        Item *dependsItem, ItemModuleList *moduleResults,
        ProductDependencyResults *productResults)
{
    checkCancelation();
    if (!checkItemCondition(dependsItem)) {
        if (m_logger.traceEnabled())
            m_logger.qbsTrace() << "Depends item disabled, ignoring.";
        return;
    }
    bool productTypesIsSet;
    const FileTags productTypes = m_evaluator->fileTagsValue(dependsItem,
            QLatin1String("productTypes"), &productTypesIsSet);
    bool nameIsSet;
    const QString name
            = m_evaluator->stringValue(dependsItem, QLatin1String("name"), QString(), &nameIsSet);
    bool submodulesPropertySet;
    QStringList submodules = m_evaluator->stringListValue(dependsItem, QLatin1String("submodules"),
                                                          &submodulesPropertySet);
    if (productTypesIsSet) {
        if (nameIsSet) {
            throw ErrorInfo(Tr::tr("The 'productTypes' and 'name' properties are mutually "
                                   "exclusive."), dependsItem->location());
        }
        if (submodulesPropertySet) {
            throw ErrorInfo(Tr::tr("The 'productTypes' and 'subModules' properties are mutually "
                                   "exclusive."), dependsItem->location());
        }
        if (productTypes.isEmpty()) {
            m_logger.qbsTrace() << "Ignoring Depends item with empty productTypes list.";
            return;
        }

        // TODO: We could also filter by the "profiles" property. This would required a refactoring
        //       (Dependency needs a list of profiles and the multiplexing must happen later).
        ModuleLoaderResult::ProductInfo::Dependency dependency;
        dependency.productTypes = productTypes;
        dependency.limitToSubProject
                = m_evaluator->boolValue(dependsItem, QLatin1String("limitToSubProject"));
        productResults->append(dependency);
        return;
    }
    if (submodules.isEmpty() && submodulesPropertySet) {
        m_logger.qbsTrace() << "Ignoring Depends item with empty submodules list.";
        return;
    }
    if (Q_UNLIKELY(submodules.count() > 1 && !dependsItem->id().isEmpty())) {
        QString msg = Tr::tr("A Depends item with more than one module cannot have an id.");
        throw ErrorInfo(msg, dependsItem->location());
    }

    QList<QualifiedId> moduleNames;
    const QualifiedId nameParts = QualifiedId::fromString(name);
    if (submodules.isEmpty()) {
        // Ignore explicit dependencies on the base module, which has already been loaded.
        if (name == QStringLiteral("qbs"))
            return;

        moduleNames << nameParts;
    } else {
        foreach (const QString &submodule, submodules)
            moduleNames << nameParts + QualifiedId::fromString(submodule);
    }

    Item::Module result;
    foreach (const QualifiedId &moduleName, moduleNames) {
        bool isRequired = m_evaluator->boolValue(dependsItem, QLatin1String("required"));
        for (int i = m_requiredChain.count() - 1; i >= 0 && isRequired; --i) {
            if (!m_requiredChain.at(i))
                isRequired = false;
        }
        const Version minVersion = Version::fromString(
                    m_evaluator->stringValue(dependsItem, QLatin1String("versionAtLeast")));
        const Version maxVersion = Version::fromString(
                    m_evaluator->stringValue(dependsItem, QLatin1String("versionBelow")));
        const VersionRange versionRange(minVersion, maxVersion);

        // Don't load the same module twice. Duplicate Depends statements can easily
        // happen due to inheritance.
        const auto it = std::find_if(moduleResults->begin(), moduleResults->end(),
                [moduleName](const Item::Module &m) { return m.name == moduleName; });
        if (it != moduleResults->end()) {
            if (isRequired)
                it->required = true;
            it->versionRange.narrowDown(versionRange);
            continue;
        }

        RequiredChainManager requiredChainManager(m_requiredChain, isRequired);

        Item *moduleItem = loadModule(dependsContext->product, parentItem, dependsItem->location(),
                                      dependsItem->id(), moduleName, isRequired, &result.isProduct);
        if (!moduleItem) {
            throw ErrorInfo(Tr::tr("Dependency '%1' not found for product '%2'.")
                            .arg(moduleName.toString(), dependsContext->product->name),
                            dependsItem->location());
        }
        if (m_logger.traceEnabled())
            m_logger.qbsTrace() << "module loaded: " << moduleName.toString();
        result.name = moduleName;
        result.item = moduleItem;
        result.required = isRequired;
        result.versionRange = versionRange;
        moduleResults->append(result);
        if (result.isProduct) {
            if (m_logger.traceEnabled())
                m_logger.qbsTrace() << "product dependency loaded: " << moduleName.toString();
            const QString profilesKey = QLatin1String("profiles");
            const QStringList profiles = m_evaluator->stringListValue(dependsItem, profilesKey);
            if (profiles.isEmpty()) {
                ModuleLoaderResult::ProductInfo::Dependency dependency;
                dependency.name = moduleName.toString();
                dependency.profile = QLatin1String("*");
                dependency.isRequired = isRequired;
                productResults->append(dependency);
                continue;
            }
            foreach (const QString &profile, profiles) {
                ModuleLoaderResult::ProductInfo::Dependency dependency;
                dependency.name = moduleName.toString();
                dependency.profile = profile;
                dependency.isRequired = isRequired;
                productResults->append(dependency);
            }
        }
    }
}

Q_NORETURN static void throwModuleNamePrefixError(const QualifiedId &shortName,
        const QualifiedId &longName, const CodeLocation &codeLocation)
{
    throw ErrorInfo(Tr::tr("The name of module '%1' is equal to the first component of the "
                           "name of module '%2', which is not allowed")
                    .arg(shortName.toString(), longName.toString()), codeLocation);
}

Item *ModuleLoader::moduleInstanceItem(Item *containerItem, const QualifiedId &moduleName)
{
    QBS_CHECK(!moduleName.isEmpty());
    Item *instance = containerItem;
    for (int i = 0; i < moduleName.count(); ++i) {
        const QString &moduleNameSegment = moduleName.at(i);
        const ValuePtr v = instance->properties().value(moduleName.at(i));
        if (v && v->type() == Value::ItemValueType) {
            instance = v.staticCast<ItemValue>()->item();
        } else {
            Item *newItem = Item::create(m_pool);
            instance->setProperty(moduleNameSegment, ItemValue::create(newItem));
            instance = newItem;
        }
        if (i < moduleName.count() - 1) {
            if (instance->type() == ItemType::ModuleInstance) {
                QualifiedId conflictingName = QStringList(moduleName.mid(0, i + 1));
                throwModuleNamePrefixError(conflictingName, moduleName, CodeLocation());
            }
            if (instance->type() != ItemType::ModulePrefix) {
                QBS_CHECK(instance->type() == ItemType::Unknown);
                instance->setType(ItemType::ModulePrefix);
            }
        }
    }
    QBS_CHECK(instance != containerItem);
    return instance;
}

Item *ModuleLoader::loadProductModule(ModuleLoader::ProductContext *productContext,
        const QString &moduleName)
{
    if (m_logger.traceEnabled())
        m_logger.qbsTrace() << "[MODLDR] loadProductModule name: " << moduleName;
    Item *module = m_productModuleCache.value(moduleName);
    if (module) {
        if (m_logger.traceEnabled())
            m_logger.qbsTrace() << "[MODLDR] loadProductModule cache hit.";
        return module;
    }
    ProductModuleInfo &pmi = productContext->project->topLevelProject->productModules[moduleName];
    module = pmi.exportItem;
    if (module) {
        if (m_logger.traceEnabled())
            m_logger.qbsTrace() << "[MODLDR] loadProductModule cache miss.";
        DependsContext dependsContext;
        dependsContext.product = productContext;
        dependsContext.productDependencies = &pmi.productDependencies;
        resolveDependencies(&dependsContext, module);
        m_productModuleCache.insert(moduleName, module);
    }
    return module;
}

class ModuleLoader::DependsChainManager
{
public:
    DependsChainManager(QStack<DependsChainEntry> &dependsChain, const QualifiedId &module,
                        const CodeLocation &dependsLocation)
        : m_dependsChain(dependsChain)
    {
        const bool alreadyInChain = std::any_of(dependsChain.cbegin(), dependsChain.cend(),
                                                [&module](const DependsChainEntry &e) {
            return e.first == module;
        });
        if (alreadyInChain) {
            ErrorInfo error;
            error.append(Tr::tr("Cyclic dependencies detected:"));
            for (auto e = m_dependsChain.cbegin(); e != m_dependsChain.cend(); ++e)
                error.append(e->first.toString(), e->second);
            error.append(module.toString(), dependsLocation);
            throw error;
        }
        m_dependsChain.push(qMakePair(module, dependsLocation));
    }

    ~DependsChainManager() { m_dependsChain.pop(); }

private:
    QStack<DependsChainEntry> &m_dependsChain;
};

Item *ModuleLoader::loadModule(ProductContext *productContext, Item *item,
        const CodeLocation &dependsItemLocation,
        const QString &moduleId, const QualifiedId &moduleName, bool isRequired,
        bool *isProductDependency)
{
    if (m_logger.traceEnabled())
        m_logger.qbsTrace() << "[MODLDR] loadModule name: " << moduleName << ", id: " << moduleId;

    DependsChainManager dependsChainManager(m_dependsChain, moduleName, dependsItemLocation);

    Item *moduleInstance = moduleId.isEmpty()
            ? moduleInstanceItem(item, moduleName)
            : moduleInstanceItem(item, QStringList(moduleId));
    if (moduleInstance->type() == ItemType::ModuleInstance) {
        // already handled
        return moduleInstance;
    }
    if (Q_UNLIKELY(moduleInstance->type() == ItemType::ModulePrefix)) {
        foreach (const Item::Module &m, item->modules()) {
            if (m.name.first() == moduleName.first())
                throwModuleNamePrefixError(moduleName, m.name, dependsItemLocation);
        }
    }
    QBS_CHECK(moduleInstance->type() == ItemType::Unknown);

    *isProductDependency = true;
    Item *modulePrototype = loadProductModule(productContext, moduleName.toString());
    if (!modulePrototype) {
        *isProductDependency = false;
        QStringList moduleSearchPaths;
        foreach (const QString &searchPath, m_reader->searchPaths())
            addExtraModuleSearchPath(moduleSearchPaths, searchPath);
        bool cacheHit = false;
        modulePrototype = searchAndLoadModuleFile(productContext, dependsItemLocation,
                moduleName, moduleSearchPaths, isRequired, &cacheHit);
        static const QualifiedId baseModuleId = QualifiedId(QLatin1String("qbs"));
        if (modulePrototype && !cacheHit && moduleName == baseModuleId)
            setupBaseModulePrototype(modulePrototype);
    }
    if (!modulePrototype)
        return 0;
    instantiateModule(productContext, nullptr, item, moduleInstance, modulePrototype,
                      moduleName, *isProductDependency);
    return moduleInstance;
}

Item *ModuleLoader::searchAndLoadModuleFile(ProductContext *productContext,
        const CodeLocation &dependsItemLocation, const QualifiedId &moduleName,
        const QStringList &extraSearchPaths, bool isRequired, bool *cacheHit)
{
    QStringList searchPaths = extraSearchPaths;
    searchPaths.append(m_moduleSearchPaths);

    bool triedToLoadModule = false;
    const QString fullName = moduleName.toString();
    foreach (const QString &path, searchPaths) {
        const QString dirPath = findExistingModulePath(path, moduleName);
        if (dirPath.isEmpty())
            continue;
        QStringList moduleFileNames = m_moduleDirListCache.value(dirPath);
        if (moduleFileNames.isEmpty()) {
            QDirIterator dirIter(dirPath, QStringList(QLatin1String("*.qbs")));
            while (dirIter.hasNext())
                moduleFileNames += dirIter.next();

            m_moduleDirListCache.insert(dirPath, moduleFileNames);
        }
        foreach (const QString &filePath, moduleFileNames) {
            triedToLoadModule = true;
            Item *module = loadModuleFile(productContext, fullName,
                                            moduleName.count() == 1
                                                && moduleName.first() == QLatin1String("qbs"),
                                            filePath, cacheHit, &triedToLoadModule);
            if (module)
                return module;
            if (!triedToLoadModule)
                m_moduleDirListCache[dirPath].removeOne(filePath);
        }
    }

    if (!isRequired)
        return createNonPresentModule(fullName, QLatin1String("not found"), nullptr);

    if (Q_UNLIKELY(triedToLoadModule))
        throw ErrorInfo(Tr::tr("Module %1 could not be loaded.").arg(fullName),
                    dependsItemLocation);

    return 0;
}

// returns QVariant::Invalid for types that do not need conversion
static QVariant::Type variantType(PropertyDeclaration::Type t)
{
    switch (t) {
    case PropertyDeclaration::UnknownType:
        break;
    case PropertyDeclaration::Boolean:
        return QVariant::Bool;
    case PropertyDeclaration::Integer:
        return QVariant::Int;
    case PropertyDeclaration::Path:
        return QVariant::String;
    case PropertyDeclaration::PathList:
        return QVariant::StringList;
    case PropertyDeclaration::String:
        return QVariant::String;
    case PropertyDeclaration::StringList:
        return QVariant::StringList;
    case PropertyDeclaration::Variant:
        break;
    }
    return QVariant::Invalid;
}

static QVariant convertToPropertyType(const QVariant &v, PropertyDeclaration::Type t,
    const QStringList &namePrefix, const QString &key)
{
    if (v.isNull() || !v.isValid())
        return v;
    const QVariant::Type vt = variantType(t);
    if (vt == QVariant::Invalid)
        return v;

    // Handle the foo,bar,bla stringlist syntax.
    if (t == PropertyDeclaration::StringList && v.type() == QVariant::String)
        return v.toString().split(QLatin1Char(','));

    QVariant c = v;
    if (!c.convert(vt)) {
        QStringList name = namePrefix;
        name << key;
        throw ErrorInfo(Tr::tr("Value '%1' of property '%2' has incompatible type.")
                        .arg(v.toString(), name.join(QLatin1Char('.'))));
    }
    return c;
}

Item *ModuleLoader::loadModuleFile(ProductContext *productContext, const QString &fullModuleName,
        bool isBaseModule, const QString &filePath, bool *cacheHit, bool *triedToLoad)
{
    checkCancelation();

    if (m_logger.traceEnabled())
        m_logger.qbsTrace() << "[MODLDR] trying to load " << fullModuleName << " from " << filePath;

    const ModuleItemCache::key_type cacheKey(filePath, productContext->profileName);
    const ItemCacheValue cacheValue = m_modulePrototypeItemCache.value(cacheKey);
    if (cacheValue.module) {
        m_logger.qbsTrace() << "[LDR] loadModuleFile cache hit for " << filePath;
        *cacheHit = true;
        return cacheValue.enabled ? cacheValue.module : 0;
    }
    *cacheHit = false;
    Item * const module = m_reader->readFile(filePath);
    if (module->type() != ItemType::Module) {
        if (m_logger.traceEnabled()) {
            m_logger.qbsTrace() << "[MODLDR] Alleged module " << fullModuleName << " has type '"
                                << module->typeName() << "', so it's not a module after all.";
        }
        *triedToLoad = false;
        return 0;
    }

    handleAllPropertyOptionsItems(module);

    if (!isBaseModule) {
        DependsContext dependsContext;
        dependsContext.product = productContext;
        dependsContext.productDependencies = &productContext->info.usedProducts;
        resolveDependencies(&dependsContext, module);
    }

    // Module properties that are defined in the profile are used as default values.
    const QVariantMap profileModuleProperties
            = productContext->moduleProperties.value(fullModuleName).toMap();
    QList<ErrorInfo> unknownProfilePropertyErrors;
    for (QVariantMap::const_iterator vmit = profileModuleProperties.begin();
            vmit != profileModuleProperties.end(); ++vmit)
    {
        if (Q_UNLIKELY(!module->hasProperty(vmit.key()))) {
            const ErrorInfo error(Tr::tr("Unknown property: %1.%2").arg(fullModuleName,
                                                                        vmit.key()));
            unknownProfilePropertyErrors.append(error);
            continue;
        }
        const PropertyDeclaration decl = module->propertyDeclaration(vmit.key());
        VariantValuePtr v = VariantValue::create(convertToPropertyType(vmit.value(), decl.type(),
                QStringList(fullModuleName), vmit.key()));
        module->setProperty(vmit.key(), v);
    }

    // Check the condition last in case the condition needs to evaluate other properties that were
    // set by the profile
    if (!checkItemCondition(module)) {
        m_logger.qbsTrace() << "[LDR] module condition is false";
        m_modulePrototypeItemCache.insert(cacheKey, ItemCacheValue(module, false));
        return 0;
    }

    foreach (const ErrorInfo &error, unknownProfilePropertyErrors)
        handlePropertyError(error, m_parameters, m_logger);

    module->setProperty(QLatin1String("name"), VariantValue::create(fullModuleName));
    m_modulePrototypeItemCache.insert(cacheKey, ItemCacheValue(module, true));
    return module;
}

Item::Module ModuleLoader::loadBaseModule(ProductContext *productContext, Item *item)
{
    const QualifiedId baseModuleName(QLatin1String("qbs"));
    Item::Module baseModuleDesc;
    baseModuleDesc.name = baseModuleName;
    baseModuleDesc.item = loadModule(productContext, item, CodeLocation(), QString(),
                                     baseModuleName, true, &baseModuleDesc.isProduct);
    QBS_CHECK(!baseModuleDesc.isProduct);
    if (Q_UNLIKELY(!baseModuleDesc.item))
        throw ErrorInfo(Tr::tr("Cannot load base qbs module."));
    return baseModuleDesc;
}

static QStringList hostOS()
{
    QStringList hostSystem;

#if defined(Q_OS_AIX)
    hostSystem << QLatin1String("aix");
#endif
#if defined(Q_OS_ANDROID)
    hostSystem << QLatin1String("android");
#endif
#if defined(Q_OS_BLACKBERRY)
    hostSystem << QLatin1String("blackberry");
#endif
#if defined(Q_OS_BSD4)
    hostSystem << QLatin1String("bsd") << QLatin1String("bsd4");
#endif
#if defined(Q_OS_BSDI)
    hostSystem << QLatin1String("bsdi");
#endif
#if defined(Q_OS_CYGWIN)
    hostSystem << QLatin1String("cygwin");
#endif
#if defined(Q_OS_DARWIN)
    hostSystem << QLatin1String("darwin");
#endif
#if defined(Q_OS_DGUX)
    hostSystem << QLatin1String("dgux");
#endif
#if defined(Q_OS_DYNIX)
    hostSystem << QLatin1String("dynix");
#endif
#if defined(Q_OS_FREEBSD)
    hostSystem << QLatin1String("freebsd");
#endif
#if defined(Q_OS_HPUX)
    hostSystem << QLatin1String("hpux");
#endif
#if defined(Q_OS_HURD)
    hostSystem << QLatin1String("hurd");
#endif
#if defined(Q_OS_INTEGRITY)
    hostSystem << QLatin1String("integrity");
#endif
#if defined(Q_OS_IOS)
    hostSystem << QLatin1String("ios");
#endif
#if defined(Q_OS_IRIX)
    hostSystem << QLatin1String("irix");
#endif
#if defined(Q_OS_LINUX)
    hostSystem << QLatin1String("linux");
#endif
#if defined(Q_OS_LYNX)
    hostSystem << QLatin1String("lynx");
#endif
#if defined(Q_OS_MACOS) || defined(Q_OS_OSX)
    hostSystem << QLatin1String("macos") << QLatin1String("osx");
#endif
#if defined(Q_OS_MSDOS)
    hostSystem << QLatin1String("msdos");
#endif
#if defined(Q_OS_NACL)
    hostSystem << QLatin1String("nacl");
#endif
#if defined(Q_OS_NETBSD)
    hostSystem << QLatin1String("netbsd");
#endif
#if defined(Q_OS_OPENBSD)
    hostSystem << QLatin1String("openbsd");
#endif
#if defined(Q_OS_OS2)
    hostSystem << QLatin1String("os2");
#endif
#if defined(Q_OS_OS2EMX)
    hostSystem << QLatin1String("os2emx");
#endif
#if defined(Q_OS_OSF)
    hostSystem << QLatin1String("osf");
#endif
#if defined(Q_OS_QNX)
    hostSystem << QLatin1String("qnx");
#endif
#if defined(Q_OS_ONX6)
    hostSystem << QLatin1String("qnx6");
#endif
#if defined(Q_OS_RELIANT)
    hostSystem << QLatin1String("reliant");
#endif
#if defined(Q_OS_SCO)
    hostSystem << QLatin1String("sco");
#endif
#if defined(Q_OS_SOLARIS)
    hostSystem << QLatin1String("solaris");
#endif
#if defined(Q_OS_SYMBIAN)
    hostSystem << QLatin1String("symbian");
#endif
#if defined(Q_OS_ULTRIX)
    hostSystem << QLatin1String("ultrix");
#endif
#if defined(Q_OS_UNIX)
    hostSystem << QLatin1String("unix");
#endif
#if defined(Q_OS_UNIXWARE)
    hostSystem << QLatin1String("unixware");
#endif
#if defined(Q_OS_VXWORKS)
    hostSystem << QLatin1String("vxworks");
#endif
#if defined(Q_OS_WIN32)
    hostSystem << QLatin1String("windows");
#endif
#if defined(Q_OS_WINCE)
    hostSystem << QLatin1String("windowsce");
#endif
#if defined(Q_OS_WINPHONE)
    hostSystem << QLatin1String("windowsphone");
#endif
#if defined(Q_OS_WINRT)
    hostSystem << QLatin1String("winrt");
#endif

    return hostSystem;
}

void ModuleLoader::setupBaseModulePrototype(Item *prototype)
{
    prototype->setProperty(QLatin1String("hostOS"), VariantValue::create(hostOS()));
    prototype->setProperty(QLatin1String("libexecPath"),
                           VariantValue::create(m_parameters.libexecPath()));

    const Version qbsVersion = Version::qbsVersion();
    prototype->setProperty(QLatin1String("versionMajor"),
                           VariantValue::create(qbsVersion.majorVersion()));
    prototype->setProperty(QLatin1String("versionMinor"),
                           VariantValue::create(qbsVersion.minorVersion()));
    prototype->setProperty(QLatin1String("versionPatch"),
                           VariantValue::create(qbsVersion.patchLevel()));
}

static void collectItemsWithId_impl(Item *item, QList<Item *> *result)
{
    if (!item->id().isEmpty())
        result->append(item);
    foreach (Item *child, item->children())
        collectItemsWithId_impl(child, result);
}

static QList<Item *> collectItemsWithId(Item *item)
{
    QList<Item *> result;
    collectItemsWithId_impl(item, &result);
    return result;
}

void ModuleLoader::instantiateModule(ProductContext *productContext, Item *exportingProduct,
        Item *instanceScope, Item *moduleInstance, Item *modulePrototype,
        const QualifiedId &moduleName, bool isProduct)
{
    const QString fullName = moduleName.toString();
    moduleInstance->setPrototype(modulePrototype);
    moduleInstance->setFile(modulePrototype->file());
    moduleInstance->setLocation(modulePrototype->location());
    QBS_CHECK(moduleInstance->type() != ItemType::ModuleInstance);
    moduleInstance->setType(ItemType::ModuleInstance);

    // create module scope
    Item *moduleScope = Item::create(m_pool);
    QBS_CHECK(instanceScope->file());
    moduleScope->setFile(instanceScope->file());
    moduleScope->setScope(instanceScope);
    QBS_CHECK(productContext->project->scope);
    productContext->project->scope->copyProperty(QLatin1String("project"), moduleScope);
    if (productContext->scope)
        productContext->scope->copyProperty(QLatin1String("product"), moduleScope);
    else
        QBS_CHECK(moduleName.toString() == QLatin1String("qbs")); // Dummy product.

    if (isProduct) {
        exportingProduct = 0;
        for (Item *exportItem = modulePrototype; exportItem && !exportingProduct;
             exportItem = exportItem->prototype()) {
            // exportItem is either of type ModuleInstance or Export. Only the latter has
            // a parent item, which is always of type Product.
            exportingProduct = exportItem->parent();
        }
        QBS_CHECK(exportingProduct);
        QBS_CHECK(exportingProduct->type() == ItemType::Product);
    }

    if (exportingProduct) {
        // TODO: For consistency with modules, it should be the other way around, i.e.
        //       "exportingProduct" and just "product".
        moduleScope->setProperty(QLatin1String("product"), ItemValue::create(exportingProduct));
        moduleScope->setProperty(QLatin1String("importingProduct"),
                                 ItemValue::create(productContext->item));

        moduleScope->setProperty(QLatin1String("project"),
                                 ItemValue::create(exportingProduct->parent()));

        PropertyDeclaration pd(QLatin1String("_qbs_sourceDir"), PropertyDeclaration::String,
                               PropertyDeclaration::PropertyNotAvailableInConfig);
        moduleInstance->setPropertyDeclaration(pd.name(), pd);
        ValuePtr v = exportingProduct->property(QLatin1String("sourceDirectory"))->clone();
        moduleInstance->setProperty(pd.name(), v);
    }

    moduleInstance->setScope(moduleScope);

    QHash<Item *, Item *> prototypeInstanceMap;
    prototypeInstanceMap[modulePrototype] = moduleInstance;

    // create instances for every child of the prototype
    createChildInstances(productContext, moduleInstance, modulePrototype, &prototypeInstanceMap);

    // create ids from from the prototype in the instance
    if (modulePrototype->file()->idScope()) {
        foreach (Item *itemWithId, collectItemsWithId(modulePrototype)) {
            Item *idProto = itemWithId;
            Item *idInstance = prototypeInstanceMap.value(idProto);
            QBS_ASSERT(idInstance, continue);
            ItemValuePtr idInstanceValue = ItemValue::create(idInstance);
            moduleScope->setProperty(itemWithId->id(), idInstanceValue);
        }
    }

    // create module instances for the dependencies of this module
    foreach (Item::Module m, modulePrototype->modules()) {
        Item *depinst = moduleInstanceItem(moduleInstance, m.name);
        const bool safetyCheck = true;
        if (safetyCheck) {
            Item *obj = moduleInstance;
            for (int i = 0; i < m.name.count(); ++i) {
                ItemValuePtr iv = obj->itemProperty(m.name.at(i));
                QBS_CHECK(iv);
                obj = iv->item();
            }
            QBS_CHECK(obj == depinst);
        }
        QBS_ASSERT(depinst != m.item, continue);
        instantiateModule(productContext, isProduct ? exportingProduct : nullptr, moduleInstance,
                          depinst, m.item, m.name, m.isProduct);
        m.item = depinst;
        moduleInstance->addModule(m);
    }

    // override module properties given on the command line
    const QVariantMap userModuleProperties
            = m_parameters.overriddenValuesTree().value(fullName).toMap();
    for (QVariantMap::const_iterator vmit = userModuleProperties.begin();
         vmit != userModuleProperties.end(); ++vmit) {
        if (Q_UNLIKELY(!moduleInstance->hasProperty(vmit.key()))) {
            const ErrorInfo error(Tr::tr("Unknown property: %1.%2")
                                  .arg(moduleName.toString(), vmit.key()));
            handlePropertyError(error, m_parameters, m_logger);
            continue;
        }
        const PropertyDeclaration decl = moduleInstance->propertyDeclaration(vmit.key());
        moduleInstance->setProperty(vmit.key(),
                VariantValue::create(convertToPropertyType(vmit.value(), decl.type(), moduleName,
                        vmit.key())));
    }
}

void ModuleLoader::createChildInstances(ProductContext *productContext, Item *instance,
                                        Item *prototype,
                                        QHash<Item *, Item *> *prototypeInstanceMap) const
{
    foreach (Item *childPrototype, prototype->children()) {
        Item *childInstance = Item::create(m_pool, childPrototype->type());
        prototypeInstanceMap->insert(childPrototype, childInstance);
        childInstance->setPrototype(childPrototype);
        childInstance->setTypeName(childPrototype->typeName());
        childInstance->setFile(childPrototype->file());
        childInstance->setLocation(childPrototype->location());
        childInstance->setScope(productContext->scope);
        Item::addChild(instance, childInstance);
        createChildInstances(productContext, childInstance, childPrototype, prototypeInstanceMap);
    }
}

void ModuleLoader::resolveProbes(ProductContext *productContext, Item *item)
{
    AccumulatingTimer probesTimer(m_parameters.logElapsedTime() ? &m_elapsedTimeProbes : nullptr);
    EvalContextSwitcher evalContextSwitcher(m_evaluator->engine(), EvalContext::ProbeExecution);
    foreach (Item *child, item->children())
        if (child->type() == ItemType::Probe)
            resolveProbe(productContext, item, child);
}

void ModuleLoader::resolveProbe(ProductContext *productContext, Item *parent, Item *probe)
{
    m_logger.qbsTrace() << "Resolving Probe at " << probe->location().toString();
    const JSSourceValueConstPtr configureScript = probe->sourceProperty(QLatin1String("configure"));
    if (Q_UNLIKELY(!configureScript))
        throw ErrorInfo(Tr::tr("Probe.configure must be set."), probe->location());
    typedef QPair<QString, QScriptValue> ProbeProperty;
    QList<ProbeProperty> probeBindings;
    QVariantMap initialProperties;
    for (Item *obj = probe; obj; obj = obj->prototype()) {
        foreach (const QString &name, obj->properties().keys()) {
            if (name == QLatin1String("configure"))
                continue;
            const QScriptValue value = m_evaluator->value(probe, name);
            probeBindings += ProbeProperty(name, value);
            if (name != QLatin1String("condition"))
                initialProperties.insert(name, value.toVariant());
        }
    }
    QScriptValue scope = m_engine->newObject();
    m_engine->currentContext()->pushScope(m_evaluator->scriptValue(parent));
    m_engine->currentContext()->pushScope(m_evaluator->fileScope(configureScript->file()));
    m_engine->currentContext()->pushScope(m_evaluator->importScope(configureScript->file()));
    m_engine->currentContext()->pushScope(scope);
    foreach (const ProbeProperty &b, probeBindings)
        scope.setProperty(b.first, b.second);
    const bool condition = m_evaluator->boolValue(probe, QLatin1String("condition"));
    const QString &uniqueProductName
            = ResolvedProduct::uniqueName(productContext->name, productContext->profileName);
    ProbeConstPtr resolvedProbe = findOldProbe(uniqueProductName, condition, initialProperties,
                                               configureScript->sourceCode().toString());
    if (!resolvedProbe)
        resolvedProbe = findCurrentProbe(probe->location(), condition, initialProperties);
    ErrorInfo evalError;
    if (!condition) {
        m_logger.qbsDebug() << "Probe disabled; skipping";
    } else if (!resolvedProbe) {
        QScriptValue sv = m_engine->evaluate(configureScript->sourceCodeForEvaluation());
        if (Q_UNLIKELY(m_engine->hasErrorOrException(sv)))
            evalError = ErrorInfo(m_engine->lastErrorString(sv), configureScript->location());
    }
    QVariantMap properties;
    foreach (const ProbeProperty &b, probeBindings) {
        const QVariant newValue = resolvedProbe
                ? resolvedProbe->properties().value(b.first) : scope.property(b.first).toVariant();
        if (newValue != b.second.toVariant())
            probe->setProperty(b.first, VariantValue::create(newValue));
        if (!resolvedProbe)
            properties.insert(b.first, newValue);
    }
    if (!resolvedProbe) {
        resolvedProbe = Probe::create(probe->location(), condition,
                configureScript->sourceCode().toString(), properties, initialProperties);
        m_currentProbes[probe->location()] << resolvedProbe;
    }
    productContext->info.probes << resolvedProbe;
    m_engine->currentContext()->popScope();
    m_engine->currentContext()->popScope();
    m_engine->currentContext()->popScope();
    m_engine->currentContext()->popScope();
    if (evalError.hasError())
        throw evalError;
}

void ModuleLoader::checkCancelation() const
{
    if (m_progressObserver && m_progressObserver->canceled()) {
        throw ErrorInfo(Tr::tr("Project resolving canceled for configuration %1.")
                    .arg(TopLevelProject::deriveId(m_parameters.finalBuildConfigurationTree())));
    }
}

bool ModuleLoader::checkItemCondition(Item *item)
{
    if (m_evaluator->boolValue(item, QLatin1String("condition"), true))
        return true;
    m_disabledItems += item;
    return false;
}

QStringList ModuleLoader::readExtraSearchPaths(Item *item, bool *wasSet)
{
    QStringList result;
    const QString propertyName = QLatin1String("qbsSearchPaths");
    const QStringList paths = m_evaluator->stringListValue(item, propertyName, wasSet);
    const JSSourceValueConstPtr prop = item->sourceProperty(propertyName);

    // Value can come from within a project file or as an overridden value from the user
    // (e.g command line).
    const QString basePath = FileInfo::path(prop ? prop->file()->filePath()
                                                 : m_parameters.projectFilePath());
    foreach (const QString &path, paths)
        result += FileInfo::resolvePath(basePath, path);
    return result;
}

void ModuleLoader::copyProperties(const Item *sourceProject, Item *targetProject)
{
    if (!sourceProject)
        return;
    const QList<PropertyDeclaration> &builtinProjectProperties = BuiltinDeclarations::instance()
            .declarationsForType(ItemType::Project).properties();
    QSet<QString> builtinProjectPropertyNames;
    foreach (const PropertyDeclaration &p, builtinProjectProperties)
        builtinProjectPropertyNames << p.name();

    for (Item::PropertyDeclarationMap::ConstIterator it
         = sourceProject->propertyDeclarations().constBegin();
         it != sourceProject->propertyDeclarations().constEnd(); ++it) {

        // We must not inherit built-in properties such as "name",
        // but there are exceptions.
        if (it.key() == QLatin1String("qbsSearchPaths") || it.key() == QLatin1String("profile")
                || it.key() == QLatin1String("buildDirectory")
                || it.key() == QLatin1String("sourceDirectory")
                || it.key() == QLatin1String("minimumQbsVersion")) {
            const JSSourceValueConstPtr &v
                    = targetProject->property(it.key()).dynamicCast<const JSSourceValue>();
            QBS_ASSERT(v, continue);
            if (v->sourceCode() == QLatin1String("undefined"))
                sourceProject->copyProperty(it.key(), targetProject);
            continue;
        }

        if (builtinProjectPropertyNames.contains(it.key()))
            continue;

        if (targetProject->properties().contains(it.key()))
            continue; // Ignore stuff the target project already has.

        targetProject->setPropertyDeclaration(it.key(), it.value());
        sourceProject->copyProperty(it.key(), targetProject);
    }
}

Item *ModuleLoader::wrapInProjectIfNecessary(Item *item)
{
    if (item->type() == ItemType::Project)
        return item;
    Item *prj = Item::create(item->pool(), ItemType::Project);
    Item::addChild(prj, item);
    prj->setTypeName(QLatin1String("Project"));
    prj->setFile(item->file());
    prj->setLocation(item->location());
    prj->setupForBuiltinType(m_logger);
    return prj;
}

QString ModuleLoader::findExistingModulePath(const QString &searchPath,
        const QualifiedId &moduleName)
{
    QString dirPath = searchPath;
    foreach (const QString &moduleNamePart, moduleName) {
        dirPath = FileInfo::resolvePath(dirPath, moduleNamePart);
        if (!FileInfo::exists(dirPath) || !FileInfo::isFileCaseCorrect(dirPath))
            return QString();
    }
    return dirPath;
}

void ModuleLoader::setScopeForDescendants(Item *item, Item *scope)
{
    foreach (Item *child, item->children()) {
        child->setScope(scope);
        setScopeForDescendants(child, scope);
    }
}

void ModuleLoader::overrideItemProperties(Item *item, const QString &buildConfigKey,
        const QVariantMap &buildConfig)
{
    const QVariant buildConfigValue = buildConfig.value(buildConfigKey);
    if (buildConfigValue.isNull())
        return;
    const QVariantMap overridden = buildConfigValue.toMap();
    for (QVariantMap::const_iterator it = overridden.constBegin(); it != overridden.constEnd();
            ++it) {
        const PropertyDeclaration decl = item->propertyDeclarations().value(it.key());
        if (!decl.isValid()) {
            ErrorInfo error(Tr::tr("Unknown property: %1.%2").arg(buildConfigKey, it.key()));
            handlePropertyError(error, m_parameters, m_logger);
            continue;
        }
        item->setProperty(it.key(),
                VariantValue::create(convertToPropertyType(it.value(), decl.type(),
                        QStringList(buildConfigKey), it.key())));
    }
}

static void collectAllModules(Item *item, QVector<Item::Module> *modules)
{
    foreach (const Item::Module &m, item->modules()) {
        auto it = std::find_if(modules->begin(), modules->end(),
                               [m] (const Item::Module &m2) { return m.name == m2.name; });
        if (it != modules->end()) {
            // If a module is required somewhere, it is required in the top-level item.
            if (m.required)
                it->required = true;
            it->versionRange.narrowDown(m.versionRange);
            continue;
        }
        modules->append(m);
        collectAllModules(m.item, modules);
    }
}

static QVector<Item::Module> allModules(Item *item)
{
    QVector<Item::Module> lst;
    collectAllModules(item, &lst);
    return lst;
}

void ModuleLoader::addTransitiveDependencies(ProductContext *ctx)
{
    if (m_logger.traceEnabled())
        m_logger.qbsTrace() << "[MODLDR] addTransitiveDependencies";
    QVector<Item::Module> transitiveDeps = allModules(ctx->item);
    std::sort(transitiveDeps.begin(), transitiveDeps.end());
    foreach (const Item::Module &m, ctx->item->modules()) {
        if (m.isProduct) {
            ctx->info.usedProducts.append(
                        ctx->project->topLevelProject->productModules.value(
                            m.name.toString()).productDependencies);
        }

        auto it = std::lower_bound(transitiveDeps.begin(), transitiveDeps.end(), m);
        QBS_CHECK(it != transitiveDeps.end() && it->name == m.name);
        transitiveDeps.erase(it);
    }
    foreach (const Item::Module &module, transitiveDeps) {
        if (module.isProduct) {
            ctx->item->addModule(module);
            ctx->info.usedProducts.append(
                        ctx->project->topLevelProject->productModules.value(
                            module.name.toString()).productDependencies);
        } else {
            Item::Module dep;
            dep.item = loadModule(ctx, ctx->item, ctx->item->location(), QString(), module.name,
                                  module.required, &dep.isProduct);
            if (!dep.item) {
                throw ErrorInfo(Tr::tr("Module '%1' not found when setting up transitive "
                                       "dependencies for product '%2'.").arg(module.name.toString(),
                                                                             ctx->name),
                                ctx->item->location());
            }
            dep.name = module.name;
            dep.required = module.required;
            dep.versionRange = module.versionRange;
            ctx->item->addModule(dep);
        }
    }
}

Item *ModuleLoader::createNonPresentModule(const QString &name, const QString &reason, Item *module)
{
    if (m_logger.traceEnabled()) {
        m_logger.qbsTrace() << "Non-required module '" << name << "' not loaded (" << reason << ")."
                            << "Creating dummy module for presence check.";
    }
    if (!module) {
        module = Item::create(m_pool, ItemType::ModuleInstance);
        module->setFile(FileContext::create());
    }
    module->setProperty(QLatin1String("present"), VariantValue::create(false));
    return module;
}

void ModuleLoader::handleProductError(const ErrorInfo &error,
                                      ModuleLoader::ProductContext *productContext)
{
    if (m_parameters.productErrorMode() == ErrorHandlingMode::Strict)
        throw error;
    m_logger.printWarning(error);
    productContext->info.hasError = true;
    productContext->project->result->productInfos.insert(productContext->item,
                                                         productContext->info);
    m_disabledItems << productContext->item;
}

void ModuleLoader::copyGroupsFromModuleToProduct(const ProductContext &productContext,
                                                 const Item *modulePrototype)
{
    for (int i = 0; i < modulePrototype->children().count(); ++i) {
        Item * const child = modulePrototype->children().at(i);
        if (child->type() == ItemType::Group) {
            Item * const clonedGroup = child->clone();
            clonedGroup->setScope(productContext.scope);
            setScopeForDescendants(clonedGroup, productContext.scope);
            Item::addChild(productContext.item, clonedGroup);
        }
    }
}

void ModuleLoader::copyGroupsFromModulesToProduct(const ProductContext &productContext)
{
    foreach (const Item::Module &module, productContext.item->modules()) {
        Item *prototype = module.item;
        bool modulePassedValidation;
        while ((modulePassedValidation = prototype->isPresentModule()
                && !prototype->delayedError().hasError())
                && prototype->prototype()) {
            prototype = prototype->prototype();
        }
        if (modulePassedValidation)
            copyGroupsFromModuleToProduct(productContext, prototype);
    }
}

QString ModuleLoaderResult::ProductInfo::Dependency::uniqueName() const
{
    return ResolvedProduct::uniqueName(name, profile);
}

} // namespace Internal
} // namespace qbs
