Android/ProjectExplorer: Fix crash when removing multiple Android Qts

That were configured for a project.

The crash is triggered by a messy combination of the Android automatic
kit creation, project window update, and automatic creation of Qt
versions and kits by the automatic project importers, including a mess
of the listener pattern without any atomicity.

- the user removes the Qt versions
- the Android plugin updates the automatic kits and individually reports
  the removed kits (*)
- that triggers an update of the project window and an update of the
  target setup page (even if that is not shown, but that's yet another
  issue)
- that triggers the project importers, which add Qt versions, which in
  turn triggers another update of automatic kits in the Android plugin -
  while that is still in the reporting loop at (*)
- that leads to the crash, because the state at this point of time is a
  mess

This minimal fix of the specific crash makes the kit update reporting in
the Android plugin at (*) "more atomic", and the same for similar code
in the iOS plugin.

Fixes: QTCREATORBUG-30347
Change-Id: I2bea6fb735abcaa34469fc43f44aa37313f70429
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/android/androidconfigurations.cpp

@@ -1470,8 +1470,7 @@ void AndroidConfigurations::updateAutomaticKitList()
     }
     // cleanup any mess that might have existed before, by removing all Android kits that
     // existed before, but weren't re-used
-    for (Kit *k : unhandledKits)
-        KitManager::deregisterKit(k);
+    KitManager::deregisterKits(unhandledKits);
 }
 
 Environment AndroidConfig::toolsEnvironment() const

src/plugins/ios/iosconfigurations.cpp

@@ -305,8 +305,7 @@ void IosConfigurations::updateAutomaticKitList()
     existingKits.subtract(resultingKits);
     qCDebug(kitSetupLog) << "Removing unused kits:";
     printKits(existingKits);
-    for (Kit *kit : std::as_const(existingKits))
-        KitManager::deregisterKit(kit);
+    KitManager::deregisterKits(toList(existingKits));
 }
 
 static IosConfigurations *m_instance = nullptr;

src/plugins/projectexplorer/kitmanager.cpp

@@ -650,16 +650,30 @@ Kit *KitManager::registerKit(const std::function<void (Kit *)> &init, Utils::Id
 
 void KitManager::deregisterKit(Kit *k)
 {
-    QTC_ASSERT(KitManager::isLoaded(), return);
+    deregisterKits({k});
+}
 
-    if (!k || !Utils::contains(d->m_kitList, k))
-        return;
-    auto taken = Utils::take(d->m_kitList, k);
-    if (defaultKit() == k) {
-        Kit *newDefault = Utils::findOrDefault(kits(), [](Kit *k) { return k->isValid(); });
-        setDefaultKit(newDefault);
+void KitManager::deregisterKits(const QList<Kit *> kitList)
+{
+    QTC_ASSERT(KitManager::isLoaded(), return);
+    std::vector<std::unique_ptr<Kit>> removed; // to keep them alive until the end of the function
+    Kit *newDefault = nullptr;
+    for (Kit *k : kitList) {
+        if (!k)
+            continue;
+        std::optional<std::unique_ptr<Kit>> taken = Utils::take(d->m_kitList, k);
+        if (!taken)
+            continue;
+        removed.push_back(std::move(*taken));
+        if (defaultKit() == k) {
+            newDefault = Utils::findOrDefault(kits(), [](Kit *k) { return k->isValid(); });
+        }
     }
-    emit instance()->kitRemoved(k);
+    if (newDefault)
+        setDefaultKit(newDefault);
+
+    for (auto it = removed.cbegin(); it != removed.cend(); ++it)
+        emit instance()->kitRemoved(it->get());
     emit instance()->kitsChanged();
 }
 

src/plugins/projectexplorer/kitmanager.h

@@ -153,6 +153,7 @@ public:
 
     static Kit *registerKit(const std::function<void(Kit *)> &init, Utils::Id id = {});
     static void deregisterKit(Kit *k);
+    static void deregisterKits(const QList<Kit *> kits);
     static void setDefaultKit(Kit *k);
 
     static void saveKits();