IssueTracker

Tried:
- Using top-of-tree branch
- Create new C++ project
- Build
- Edit app/build.gradle
- Accept Android Studio prompt to sync
- Build
- Outcome for each edit I tried
  1) Insert a comment in build.gradle: No rebuild as expected
  2) Delete a dependency in build.gradle: No rebuild as expected

I'll try 3.6 ToT now

Looking at json_generation_record.json I see:
  {
    "level": "INFO",
    "message": "- force flag, will remove stale json folder",
    "file": "/Users/aclement/Documents/iZoSrc/hook-android/Spire/spire_native/CMakeLists.txt",
    "tag": "debug|arm64-v8a"
  },

It looks like probably the force flag has been set somewhere.

I was able to repro this with a simpler test case in both 3.6 and 4.1 Canary. Hope this can help.

* Uninstall previous version of Android Studio 3.6 and clear preferences (rm -rf ~/Library/Preferences/AndroidStudio3.6)
* Install Android Studio 3.6.1
** Select “Do not import settings” in dialog
** Select “Standard” install type
* In the new project wizard, select “Native C++”
** Use default minSDK and default C++ toolchain
* Wait for initial sync to complete
* Build -> Make Project
** Build Output shows “[1/2] Building CXX object …” for each architecture. Also present in the android_gradle_build_native-lib_<arch>.stdout.txt.
* In /app/build.gradle, downgrade androidx.appcompat:appcompat to 1.0.0
* Click “Sync Now” in top notification
** All files in .cxx/debug/x86 (the active build variant in the Build Variant tab) will update (the modified dates update). Files in the non-active build variant will not update.
json_generation_record.json now contains “- force flag, will remove stale json folder”
* Build -> Make Project
** Build Output shows “Building CXX object CMakeFiles/native-lib.dir/native-lib.cpp.o” under “Build native-lib_x86” and “ninja: no work to do.” for other, non-active ABIs. Ditto in the android_gradle_build_native-lib_<arch>.stdout.txt files.

The force flag appears to be set during the Gradle sync after updating the androidx dependency. I've also learned that the rebuild only seems to occur for the configuration active in the Build Variants tab.

I’ve attached three copies of the .cxx folder again, from different points in time: after the initial build, after updating the dependency and syncing, and after the build after that sync. I’m on MacOS Catalina 10.15.2, MacBook Pro (15-inch, 2017).

I did some digging in AS’s source and found a reference to an older issue in ExternalNativeJsonGenerator.java that seems similar (albeit slightly different): https://issuetracker.google.com/issues/69408798. This StackOverflow question (https://stackoverflow.com/q/58063705/4817013) also seems to be a similar issue and was opened recently, perhaps highlighting that this could be a recent regression.

This is currently blocking my team from updating from 3.4 and we would really like to! Please let me know if there’s any other data I can get to help you out.

Thanks,
Alex

I've submitted a fix for this one. It should be available in AS 4.1 canary 4

I've confirmed this is fixed in AS 4.1 canary 4. Thank you both very much!

A heads up: this was included in the release notes for 3.6.2 but does not appear to be fixed in that version.