"Don't run resource union in MiniAapt" #2086 appears to break resource merging

https://github.com/facebook/buck/pull/2086 appears to have broken our app’s resource merging.

Specific breakage I noticed (the earliest breakage): we have an ids.xml with a placeholder id in a package com.my.package

The generated class appears to be found in buck-out/bin/common/my/other/package/lib__src_debug#dummy_r_dot_java__scratch/classes/com/my/package/containerconstants/R$id.class class file, but compiling the app fails with error: cannot find symbol when referenced from another package.

After reverting this change, our app compiles normally with Buck again.

[alexjlockwood]

@raviagarwal7 @kageiit I have a branch that reproduces the error we are seeing: https://github.com/uber/okbuck/pull/826

[raviagarwal7]

@raviagarwal7 @kageiit I have a branch that reproduces the error we are seeing: uber/okbuck#826

@artem-zinnatullin, does this shows the behaviour that broke with the pr #2086?

If resource union is needed doing union in MergeAndroidResourcesStep is the right way to go which handles styleable correctly. I think the resource_union flag can be removed from android_resource (missed removing it in that pr) and needs to be added to android_binary and robolectric_test.

setting resourceUnion would enable resource union with the original package otherwise uses the specified package. setting resourceUnionPackage uses this as the union package.

Seems like gradle has the same default behaviour and I think this change in BUCK will make it work similarly.

So, this requires 2 changes:

• change buck to handle original package name resource union correctly and remove the flag from android_resource.
• change okbuck to remove outputting resource_union from android_resource and output correctly according to the above change.

From OkBuck docs.

  /**
   * Set to use buck's resource_union behavior with the original package name or the defined by
   * {@link OkBuckExtension#resourceUnionPackage}
   */
  @Input public boolean resourceUnion;

  /** Set to use buck's resource_union behavior with an specific package name */
  @Nullable @Input public String resourceUnionPackage;

feel free to create PR’s and cc me on it.