Fix missing path separator in prepare_resources-mac.py

[adamnsch]

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Description

Fixes a bug in the macOS resource copying script where TARGET_BUILD_DIR and UNLOCALIZED_RESOURCES_FOLDER_PATH were concatenated without a path separator, causing resources to be copied to an invalid path.

Before: /Users/name/ApplicationsApp.app/Contents/Resources (missing slash)
After: /Users/name/Applications/App.app/Contents/Resources (correct)

This caused the standalone app to crash on startup with a segmentation fault when trying to render UI elements with missing bitmaps.

PR Checklist (none are applicable for this change)

• Did you format your code using format.bash?
• Does the VST3 plugin pass all of the unit tests in the VST3PluginTestHost? (Download it as part of the VST3 SDK here.)
  • Windows
  • macOS
• Does your PR add, remove, or rename any plugin parameters? If yes...
  • Have you ensured that the plug-in unserializes correctly?
  • Have you ensured that older versions of the plug-in load correctly? (See Unserialization.cpp.)
• Does your PR add or remove any graphical assets? If yes, are they defined in config.h and added in the two required locations in main.rc?

[sdatkinson]

Nice. Two questions if you know:

• Users have reported the AU crashing in Logic. I wonder if this is the root cause.
• Any suggestions how this might be asserted in a test? It'd be good for this to stay fixed :)

[adamnsch]

Hi @sdatkinson,

Users have reported the AU crashing in Logic. I wonder if this is the root cause.

Yes, that might be the issue. Do you have any bug reports/stack traces? I don't think it should impact AU and Logic specifically though, and I'm an Ableton user myself so cannot really test it

Any suggestions how this might be asserted in a test? It'd be good for this to stay fixed :)

Yes, I think we could add something this to .github/workflows/build-native.yml:

    - name: Verify macOS bundle resources
      if: matrix.os == 'macOS-latest'
      run: |
        # Unzip the built artifact to verify resources were copied correctly
        cd ${{env.PROJECT_NAME}}/${{matrix.build_dir}}/out
        unzip -q *-mac.zip -d verify_tmp

        # Check each plugin bundle has resources
        for BUNDLE in verify_tmp/*.component verify_tmp/*.vst3; do
          if [ ! -d "$BUNDLE" ]; then
            continue
          fi

          RESOURCES="$BUNDLE/Contents/Resources"
          BUNDLE_NAME=$(basename "$BUNDLE")

          if [ ! -d "$RESOURCES" ]; then
            echo "ERROR: Resources directory missing in $BUNDLE_NAME"
            rm -rf verify_tmp
            exit 1
          fi

          COUNT=$(ls -1 "$RESOURCES" 2>/dev/null | wc -l)
          if [ "$COUNT" -eq 0 ]; then
            echo "ERROR: Resources directory is empty in $BUNDLE_NAME"
            rm -rf verify_tmp
            exit 1
          fi

          echo "$BUNDLE_NAME has $COUNT resources"
        done

        # Cleanup
        rm -rf verify_tmp
        echo "All macOS bundles verified successfully"
      shell: bash

At least it works locally on my machine (fails before fix, and passes after). We could also verify the path directly in the prepare_resources-mac.py script, but that kind of depends on an implementation detail and is less robust I think

Btw, let me know if you have any good "first issues" or smaller projects you want me to pick up. Would love to contribute more to this fantastic project :)