Android: keep the platform minor revision for the compile SDK

Google ships no plain android-37 platform, only android-37.0
and later. Gradle resolves a bare API level to the base
revision only, so dropping the minor picks the wrong platform,
or none at all when just android-37.1 is installed.

Write the selected platform verbatim, detect the latest one by
its real directory name, and reduce it to the API level only
for build.gradle files that convert it to an integer.

Pick-to: 6.12 6.11 6.8
Fixes: QTBUG-149770
Change-Id: Idf487ba2522928dd200ccb9c43b082d17abdb56f
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

Author: Issam-b

src/tools/androiddeployqt/main.cpp

@@ -707,13 +707,15 @@ Optional arguments:
 // gives the natural order.
 bool quasiLexicographicalReverseLessThan(const QFileInfo &fi1, const QFileInfo &fi2)
 {
+    // baseName() drops the minor, so sort by API level, then by minor.
     QString s1 = fi1.baseName();
     QString s2 = fi2.baseName();
 
-    if (s1.size() == s2.size())
-        return s1 > s2;
-    else
+    if (s1.size() != s2.size())
         return s1.size() > s2.size();
+    if (s1 != s2)
+        return s1 > s2;
+    return fi1.fileName() > fi2.fileName();
 }
 
 // Files which contain templates that need to be overwritten by build data should be overwritten every
@@ -913,8 +915,11 @@ QString detectLatestAndroidPlatform(const QString &sdkPath)
 
     std::sort(fileInfos.begin(), fileInfos.end(), quasiLexicographicalReverseLessThan);
 
+    // Prefer the plain name any AGP understands, else the minor revision.
     const QFileInfo& latestPlatform = fileInfos.constFirst();
-    return latestPlatform.baseName();
+    if (dir.exists(latestPlatform.baseName()))
+        return latestPlatform.baseName();
+    return latestPlatform.fileName();
 }
 
 QString extractPackageName(Options *options)
@@ -3116,7 +3121,16 @@ bool buildAndroidProject(const Options &options)
     // Provide the integer version only if build.gradle explicitly converts to Integer,
     // to avoid regression to existing projects that build for sdk platform of form android-xx.
     if (gradleConfigs.usesIntegerCompileSdkVersion) {
-        const QByteArray tmp = options.androidPlatform.split(u'-').last().toLocal8Bit();
+        // An integer holds no minor, and Gradle resolves it to android-xx.0.
+        const QStringList platformParts = options.androidPlatform.split(u'-').last().split(u'.');
+        const QString apiLevel = platformParts.constFirst();
+        if (platformParts.size() > 1 && platformParts.at(1) != "0"_L1) {
+            fprintf(stderr,
+                "Warning: build.gradle takes an integer compile SDK version, "
+                "building against API level %s instead of platform %s.\n",
+                qPrintable(apiLevel), qPrintable(options.androidPlatform));
+        }
+        const QByteArray tmp = apiLevel.toLocal8Bit();
         bool ok;
         tmp.toInt(&ok);
         if (ok) {