Use package and resource name when computing referenced resource names in dex

src/com/facebook/buck/android/TrimUberRDotJava.java

@@ -58,6 +58,9 @@ class TrimUberRDotJava extends AbstractBuildRule {
   private static final Pattern R_DOT_JAVA_LINE_PATTERN = Pattern.compile(
       "^ *public static final int(?:\\[\\])? (\\w+)=");
 
+  private static final Pattern R_DOT_JAVA_PACKAGE_NAME_PATTERN = Pattern.compile(
+      "^ *package ([\\w.]+);");
+
   TrimUberRDotJava(
       BuildRuleParams buildRuleParams,
       SourcePathResolver resolver,
@@ -176,12 +179,22 @@ private static void filterRDotJava(
       OutputStream output,
       ImmutableSet<String> allReferencedResources)
       throws IOException {
+    String packageName = null;
+    Matcher m;
     for (String line : rDotJavaLines) {
-      Matcher m = R_DOT_JAVA_LINE_PATTERN.matcher(line);
-      // We ignore the containing nested class and just match on the resource name.
+      if (packageName == null) {
+        m = R_DOT_JAVA_PACKAGE_NAME_PATTERN.matcher(line);
+        if (m.find()) {
+          packageName = m.group(1);
+        } else {
+          continue;
+        }
+      }
+      m = R_DOT_JAVA_LINE_PATTERN.matcher(line);
+      // We match on the package name + resource name.
       // This can cause us to keep (for example) R.layout.foo when only R.string.foo
       // is referenced.  That is a very rare case, though, and not worth the complexity to fix.
-      if (m.find() && !allReferencedResources.contains(m.group(1))) {
+      if (m.find() && !allReferencedResources.contains(packageName + "." + m.group(1))) {
         continue;
       }
       output.write(line.getBytes(Charsets.UTF_8));

test/com/facebook/buck/android/AndroidBinaryIntegrationTest.java

@@ -243,7 +243,7 @@ public void testDxFindsReferencedResources() throws IOException {
         buildInfo.getValues(DexProducedFromJavaLibrary.REFERENCED_RESOURCES);
     assertTrue(resourcesFromMetadata.isPresent());
     assertEquals(
-        ImmutableSet.of("title", "top_layout"),
+        ImmutableSet.of("com.sample.top_layout", "com.sample2.title"),
         ImmutableSet.copyOf(resourcesFromMetadata.get()));
   }
 

test/com/facebook/buck/android/TrimUberRDotJavaTest.java

@@ -99,7 +99,7 @@ public void testTrimming() throws IOException, InterruptedException {
             .putMetadata(DexProducedFromJavaLibrary.CLASSNAMES_TO_HASHES, "{}")
             .putMetadata(
                 DexProducedFromJavaLibrary.REFERENCED_RESOURCES,
-                ImmutableList.of("my_first_resource"))));
+                ImmutableList.of("com.test.my_first_resource"))));
 
     TrimUberRDotJava trimUberRDotJava = new TrimUberRDotJava(
         new FakeBuildRuleParamsBuilder(BuildTargetFactory.newInstance("//:trim"))

third-party/java/dx/src/com/android/dx/command/dexer/Main.java

@@ -1654,8 +1654,8 @@ private void computeReferencedResources() {
             CstType fieldClass = item.getDefiningClass();
             CstString fieldName = item.getRef().getNat().getName();
             if (fieldClass.getClassType().getDescriptor().contains("/R$")) {
-                // We ignore the name of the containing class for simplicity.
-                resourceNames.add(fieldName.getString());
+                // Add the packageName of the class for better accuracy.
+                resourceNames.add(fieldClass.getPackageName() + "." + fieldName.getString());
             }
         }
     }