Improve kit auto-detection

The old code was too simplistic: Basically, we just took a random
toolchain, slapped a random Qt onto it and made that the default kit.
Instead, we now go through all toolchains, try to find a matching Qt
version, debugger etc and create a kit for that combination unless there
is a better one.

Fixes: QTCREATORBUG-22138
Change-Id: Ib57ca4453a93ee9253c75398328c3bca33087dc6
Reviewed-by: hjk <hjk@qt.io>

2 files changed, 42 insertions, 11 deletions

diff --git a/src/plugins/qtsupport/qtkitinformation.cpp b/src/plugins/qtsupport/qtkitinformation.cpp
index 1181e5b359d..3cd0b2d36b7 100644
--- a/src/plugins/qtsupport/qtkitinformation.cpp
+++ b/src/plugins/qtsupport/qtkitinformation.cpp
@@ -163,17 +163,32 @@ QtKitAspect::QtKitAspect()
 
 void QtKitAspect::setup(ProjectExplorer::Kit *k)
 {
-    Q_UNUSED(k);
-
-    // find "Qt in PATH":
-    BaseQtVersion *result = QtVersionManager::version(equal(&BaseQtVersion::autodetectionSource,
-                                                            QString::fromLatin1("PATH")));
-    if (!result) {
-        // Use *any* desktop Qt:
-        result = QtVersionManager::version(equal(&BaseQtVersion::type,
-            QString::fromLatin1(QtSupport::Constants::DESKTOPQT)));
-    }
-    k->setValue(id(), result ? result->uniqueId() : -1);
+    const Abi tcAbi = ToolChainKitAspect::targetAbi(k);
+    const Core::Id deviceType = DeviceTypeKitAspect::deviceTypeId(k);
+
+    const QList<BaseQtVersion *> matches
+            = QtVersionManager::versions([&tcAbi, &deviceType](const BaseQtVersion *qt) {
+        return qt->targetDeviceTypes().contains(deviceType)
+                && Utils::contains(qt->qtAbis(), [&tcAbi](const Abi &qtAbi) {
+            return qtAbi.isCompatibleWith(tcAbi); });
+    });
+    if (matches.empty())
+        return;
+
+    // An MSVC 2015 toolchain is compatible with an MSVC 2017 Qt, but we prefer an
+    // MSVC 2015 Qt if we find one.
+    const QList<BaseQtVersion *> exactMatches = Utils::filtered(matches,
+                                                                [&tcAbi](const BaseQtVersion *qt) {
+        return qt->qtAbis().contains(tcAbi);
+    });
+    const QList<BaseQtVersion *> &candidates = !exactMatches.empty() ? exactMatches : matches;
+
+    BaseQtVersion * const qtFromPath = QtVersionManager::version(
+                equal(&BaseQtVersion::autodetectionSource, QString::fromLatin1("PATH")));
+    if (qtFromPath && candidates.contains(qtFromPath))
+        k->setValue(id(), qtFromPath->uniqueId());
+    else
+        k->setValue(id(), candidates.first()->uniqueId());
 }
 
 QList<ProjectExplorer::Task> QtKitAspect::validate(const ProjectExplorer::Kit *k) const
@@ -370,4 +385,18 @@ QSet<Core::Id> QtKitAspect::availableFeatures(const Kit *k) const
     return version ? version->features() : QSet<Core::Id>();
 }
 
+int QtKitAspect::weight(const Kit *k) const
+{
+    const BaseQtVersion * const qt = qtVersion(k);
+    if (!qt)
+        return 0;
+    if (!qt->targetDeviceTypes().contains(DeviceTypeKitAspect::deviceTypeId(k)))
+        return 0;
+    const Abi tcAbi = ToolChainKitAspect::targetAbi(k);
+    if (qt->qtAbis().contains(tcAbi))
+        return 2;
+    return Utils::contains(qt->qtAbis(), [&tcAbi](const Abi &qtAbi) {
+        return qtAbi.isCompatibleWith(tcAbi); }) ? 1 : 0;
+}
+
 } // namespace QtSupport
diff --git a/src/plugins/qtsupport/qtkitinformation.h b/src/plugins/qtsupport/qtkitinformation.h
index 5a9be938029..565e5aef0f9 100644
--- a/src/plugins/qtsupport/qtkitinformation.h
+++ b/src/plugins/qtsupport/qtkitinformation.h
@@ -73,6 +73,8 @@ public:
     QSet<Core::Id> availableFeatures(const ProjectExplorer::Kit *k) const override;
 
 private:
+    int weight(const ProjectExplorer::Kit *k) const override;
+
     void qtVersionsChanged(const QList<int> &addedIds,
                            const QList<int> &removedIds,
                            const QList<int> &changedIds);