Add a main_dex_proguard_specs attribute to android_binary that lets users specify which classes should go into the main dex.

This mode uses Proguard to determine the dependencies of these classes, which means that no error-prone manual listing required like in multidex="manual" mode.

RELNOTES: android_binary now has a main_dex_proguard_specs attribute to specify which classes should be in the main dex.

--
MOS_MIGRATED_REVID=103824119

2 files changed, 31 insertions, 5 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidBinary.java b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidBinary.java
index 81db9ac7cf..e0a057fe97 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/android/AndroidBinary.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/android/AndroidBinary.java
@@ -121,6 +121,15 @@ public abstract class AndroidBinary implements RuleConfiguredTargetFactory {
       JavaSemantics javaSemantics,
       AndroidSemantics androidSemantics,
       List<String> depsAttributes) throws InterruptedException {
+
+    if (getMultidexMode(ruleContext) != MultidexMode.LEGACY
+        && ruleContext.attributes().isAttributeValueExplicitlySpecified(
+            "main_dex_proguard_specs")) {
+      ruleContext.attributeError("main_dex_proguard_specs", "The 'main_dex_proguard_specs' "
+          + "attribute is only allowed if 'multidex' is set to 'legacy'");
+      return null;
+    }
+
     // TODO(bazel-team): Find a way to simplify this code.
     // treeKeys() means that the resulting map sorts the entries by key, which is necessary to
     // ensure determinism.
@@ -1005,7 +1014,7 @@ public abstract class AndroidBinary implements RuleConfiguredTargetFactory {
     // Process the input jar through Proguard into an intermediate, streamlined jar.
     Artifact strippedJar = AndroidBinary.getDxArtifact(ruleContext, "main_dex_intermediate.jar");
     AndroidSdkProvider sdk = AndroidSdkProvider.fromRuleContext(ruleContext);
-    ruleContext.registerAction(new SpawnAction.Builder()
+    SpawnAction.Builder streamlinedBuilder = new SpawnAction.Builder()
         .addOutput(strippedJar)
         .setExecutable(sdk.getProguard())
         .setProgressMessage("Generating streamlined input jar for main dex classes list")
@@ -1021,10 +1030,20 @@ public abstract class AndroidBinary implements RuleConfiguredTargetFactory {
         .addArgument("-forceprocessing")
         .addArgument("-dontoptimize")
         .addArgument("-dontobfuscate")
-        .addArgument("-dontpreverify")
-        .addArgument("-include")
-        .addInputArgument(sdk.getMainDexClasses())
-        .build(ruleContext));
+        .addArgument("-dontpreverify");
+
+    List<Artifact> specs = ruleContext.getPrerequisiteArtifacts(
+        "main_dex_proguard_specs", Mode.TARGET).list();
+    if (specs.isEmpty()) {
+      specs = ImmutableList.of(sdk.getMainDexClasses());
+    }
+
+    for (Artifact spec : specs) {
+      streamlinedBuilder.addArgument("-include");
+      streamlinedBuilder.addInputArgument(spec);
+    }
+
+    ruleContext.registerAction(streamlinedBuilder.build(ruleContext));
 
     // Create the main dex classes list.
     Artifact mainDexList = AndroidBinary.getDxArtifact(ruleContext, "main_dex_list.txt");
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 2b80cb1b7a..bbab1a54ab 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
@@ -650,6 +650,13 @@ com/google/common/base/Objects.class
           Must be used with <code>multidex="manual_main_dex"</code>.
           <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
           .add(attr("main_dex_list", LABEL).legacyAllowAnyFileType())
+          /* <!-- #BLAZE_RULE($android_binary_base).ATTRIBUTE(main_dex_proguard_specs) -->
+          Files to be used as the Proguard specifications to determine classes that must be kept in
+          the main dex.
+          ${SYNOPSIS}
+          Only allowed if the <code>multidex</code> attribute is set to <code>legacy</code>.
+          <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
+          .add(attr("main_dex_proguard_specs", LABEL_LIST).legacyAllowAnyFileType())
           /* <!-- #BLAZE_RULE($android_binary_base).ATTRIBUTE(proguard_specs) -->
           Files to be used as Proguard specification.
           ${SYNOPSIS}