Starlark aar_import does not expose StarlarkAndroidResourcesInfo

[katre]

Discovered while testing bazelbuild/examples#287.

When building examples/android/ndk with rules_android master branch, the build succeeds. The ManifestMerger action has the --mergeeManfests argument set to a list of manifest files, which includes @maven//\:androidx_appcompat_appcompat,bazel-out/android-arm64-v8a-fastbuild-ST-0b94fd089017/bin/external/maven/androidx_appcompat_appcompat_resources_processed_manifest/AndroidManifest.xml

When building with the pre-alpha branch, the ManifestMerger does not set the flag, and the merge action fails (presumably due to the lack of needed dependencies).

[katre]

Looks like the issue is RourceDependencies.fromRuleDeps, which is looking for the AndroidResourceInfo.PROVIDER provider. This is present with the master branch, but not with the pre-alpha, which I assume is due to starlarkifying android_library.

[katre]

Yes, looks like the native android_library calls AndroidResources.from, which collects the AndroidResourceInfo providers, but the version in pre-alpha does not.

[katre]

Okay, finally figured out the issue.

The pre-alpha version of resource collection (as implemented in rules/resources.bzl only checks for the existence of StarlarkAndroidResourcesInfo, not the native AndroidResourcesInfo.

The Starlark version of aar_import creates this provider, as expected.

However, the code in examples/android/ndk depends on appcompat via maven_install from rules_jvm_external, which creates an aar_import target using the native rules, which uses the native provider.

Either the pre-alpha branch needs to check for both possible providers, or rules_jvm_export needs to use the same pre-alpha version of aar_import, or rules_jvm_export isn't compatible with rules_android pre-alpha.

[katre]

Looks like rules_jvm_external has support for this, possibly.

[katre]

But even using the starlark aar_import, the target @maven//:androidx_appcompat_appcompat doesn't have the StarlarkAndroidResourcesInfo provider.

Using native aar_import to list provider names:

$ /tmp/blazes/bazel cquery --output=starlark --starlark:expr='providers(target).keys()' @maven//:androidx_appcompat_appcompat_resources
[
  "InstrumentedFilesInfo",
  "AndroidResourcesInfo",
  "AndroidManifestInfo",
  "AndroidAssetsInfo",
  "DataBindingV2Info",
  "ProguardSpecProvider",
  "AndroidNativeLibsInfo",
  "JavaInfo",
  "FileProvider",
  "FilesToRunProvider",
  "OutputGroupInfo",
]

Using Starlark aar_import to list provider names:

$ /tmp/blazes/bazel cquery --output=starlark --starlark:expr='providers(target).keys()' @maven//:androidx_appcompat_appcompat_resources
[
  "AndroidLibraryResourceClassJarProvider",
  "JavaInfo",
  "AndroidNativeLibsInfo",
  "ProguardSpecProvider",
  "AndroidIdeInfo",
  "FileProvider",
  "FilesToRunProvider",
  "OutputGroupInfo",
]

[katre]

Retitled issue to clarify the root cause.

[ted-xie]

This should be fixed if/when we merge https://github.com/bazelbuild/rules_android/pull/52/files#diff-e2839f4bd7500de02db70226d1fb363bc1bcd62e2ac7046594dafc3e7040fa09.

[ThomasCJY]

Is this issue fixed in #224?