android_library can be used in the resources attribute

This allows us to perform a more gradual migration away from the
android_resources rule. Specifically, rather than move all android_resources
targets and simultaneously move all resources attributes, we can now first
transform all android_resources rules into android_library rules, and then
afterwards migrate dependencies on those rules from resources into deps. This
allows a two-part migration.

The resources attribute, once allowed to take android_library targets, should
continue to work exactly as before.

There is one change in behavior - for this to work, android_library targets now
need to build an output APK during resource processing. This APK will be
removed once the resources attribute is removed.

Once the migration is complete, the resources attribute will be removed
completely.

RELNOTES: none
PiperOrigin-RevId: 165313447

3 files changed, 21 insertions, 1 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidResourceValidatorActionBuilder.java b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidResourceValidatorActionBuilder.java
index 37a42e1584..40ae0972e8 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidResourceValidatorActionBuilder.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidResourceValidatorActionBuilder.java
@@ -56,6 +56,7 @@ public class AndroidResourceValidatorActionBuilder {
   private Artifact aapt2SourceJarOut;
   private Artifact aapt2RTxtOut;
   private Artifact compiledSymbols;
+  private Artifact apkOut;
 
   /** @param ruleContext The RuleContext that was used to create the SpawnAction.Builder. */
   public AndroidResourceValidatorActionBuilder(RuleContext ruleContext) {
@@ -131,6 +132,11 @@ public class AndroidResourceValidatorActionBuilder {
     return this;
   }
 
+  public AndroidResourceValidatorActionBuilder setApkOut(Artifact apkOut) {
+    this.apkOut = apkOut;
+    return this;
+  }
+
   /**
    * This creates a static library using aapt2. It also generates a source jar and R.txt from aapt.
    *
@@ -254,6 +260,11 @@ public class AndroidResourceValidatorActionBuilder {
     builder.add("--srcJarOutput", sourceJarOut);
     outs.add(sourceJarOut);
 
+    if (apkOut != null) {
+      builder.add("--packagePath", apkOut);
+      outs.add(apkOut);
+    }
+
     SpawnAction.Builder spawnActionBuilder = new SpawnAction.Builder();
     // Create the spawn action.
     ruleContext.registerAction(
diff --git a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidRuleClasses.java b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidRuleClasses.java
index 88a6e27636..4e1fe7ffdc 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidRuleClasses.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidRuleClasses.java
@@ -84,6 +84,10 @@ public final class AndroidRuleClasses {
       JavaSemantics.JAVA_LIBRARY_CLASS_JAR;
   public static final SafeImplicitOutputsFunction ANDROID_LIBRARY_AAR =
       fromTemplates("%{name}.aar");
+  // TODO(b/30307842): Remove this once it is no longer needed for resources migration.
+  public static final SafeImplicitOutputsFunction ANDROID_LIBRARY_APK =
+      fromTemplates("%{name}_files/library.ap_");
+
   /**
    * Source Jar for {@link #ANDROID_RESOURCES_CLASS_JAR}, which should be the same as
    * {@link #ANDROID_JAVA_SOURCE_JAR}.
diff --git a/src/main/java/com/google/devtools/build/lib/rules/android/ApplicationManifest.java b/src/main/java/com/google/devtools/build/lib/rules/android/ApplicationManifest.java
index a40afd09dc..01031e9dee 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/android/ApplicationManifest.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/android/ApplicationManifest.java
@@ -505,7 +505,11 @@ public final class ApplicationManifest {
             .setAssetsAndResourcesFrom(data)
             .setManifest(getManifest())
             .setSymbols(symbols)
-            .setRTxt(rTxt);
+            .setRTxt(rTxt)
+            // Request an APK so it can be inherited when a library is used in a binary's
+            // resources attr.
+            // TODO(b/30307842): Remove this once it is no longer needed for resources migration.
+            .setApk(ruleContext.getImplicitOutputArtifact(AndroidRuleClasses.ANDROID_LIBRARY_APK));
 
     if (targetAaptVersion == AndroidAaptVersion.AAPT2) {
 
@@ -631,6 +635,7 @@ public final class ApplicationManifest {
               .withPrimary(merged)
               .setRTxtOut(merged.getRTxt())
               .setSourceJarOut(merged.getJavaSourceJar())
+              .setApkOut(resourceContainer.getApk())
               // aapt2 related artifacts. Will be generated if the targetAaptVersion is AAPT2.
               .withDependencies(resourceDeps)
               .setCompiledSymbols(merged.getCompiledSymbols())