Fix Android data binding for rules with no direct resources.

This essentially works by activating the annotation processor
over such rules, even though technically that's unnecessary (since
there are no new resources to process). But running the annotation
processor guarantees we still process deps' resources, which
guarantees the Java compiler references any Java classes
mentioned in those resources.

This prevents JavaBuilder's ---reduce_classpath from pruning these
files out of the compilation classpath because "they were never used".

PiperOrigin-RevId: 159597671

1 files changed, 62 insertions, 35 deletions

diff --git a/src/test/java/com/google/devtools/build/lib/rules/android/AndroidDataBindingTest.java b/src/test/java/com/google/devtools/build/lib/rules/android/AndroidDataBindingTest.java
index 8569eaeb0e..7f51679603 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/android/AndroidDataBindingTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/android/AndroidDataBindingTest.java
@@ -57,6 +57,40 @@ public class AndroidDataBindingTest extends AndroidBuildViewTestCase {
         "package android.binary; public class MyApp {};");
   }
 
+  private void writeDataBindingFilesWithNoResourcesDep() throws Exception {
+    scratch.file("java/android/lib_with_resource_files/BUILD",
+        "android_library(",
+        "    name = 'lib_with_resource_files',",
+        "    enable_data_binding = 1,",
+        "    manifest = 'AndroidManifest.xml',",
+        "    srcs = ['LibWithResourceFiles.java'],",
+        "    resource_files = glob(['res/**']),",
+        ")");
+    scratch.file("java/android/lib_with_resource_files/LibWithResourceFiles.java",
+        "package android.lib_with_resource_files; public class LibWithResourceFiles {};");
+
+    scratch.file("java/android/lib_no_resource_files/BUILD",
+        "android_library(",
+        "    name = 'lib_no_resource_files',",
+        "    enable_data_binding = 1,",
+        "    srcs = ['LibNoResourceFiles.java'],",
+        "    deps = ['//java/android/lib_with_resource_files'],",
+        ")");
+    scratch.file("java/android/lib_no_resource_files/LibNoResourceFiles.java",
+        "package android.lib_no_resource_files; public class LibNoResourceFiles {};");
+
+    scratch.file("java/android/binary/BUILD",
+        "android_binary(",
+        "    name = 'app',",
+        "    enable_data_binding = 1,",
+        "    manifest = 'AndroidManifest.xml',",
+        "    srcs = ['MyApp.java'],",
+        "    deps = ['//java/android/lib_no_resource_files'],",
+        ")");
+    scratch.file("java/android/binary/MyApp.java",
+        "package android.binary; public class MyApp {};");
+  }
+
   /**
    * Returns the .params file contents of a {@link JavaCompileAction}
    */
@@ -186,44 +220,11 @@ public class AndroidDataBindingTest extends AndroidBuildViewTestCase {
 
   @Test
   public void dataBindingIncludesTransitiveDepsForLibsWithNoResources() throws Exception {
-    scratch.file("java/android/lib_with_resource_files/BUILD",
-        "android_library(",
-        "    name = 'lib_with_resource_files',",
-        "    enable_data_binding = 1,",
-        "    manifest = 'AndroidManifest.xml',",
-        "    srcs = ['LibWithResourceFiles.java'],",
-        "    resource_files = glob(['res/**']),",
-        ")");
-    scratch.file("java/android/lib_with_resource_files/LibWithResourceFiles.java",
-        "package android.lib_with_resource_files; public class LibWithResourceFiles {};");
-
-    scratch.file("java/android/lib_no_resource_files/BUILD",
-        "android_library(",
-        "    name = 'lib_no_resource_files',",
-        "    enable_data_binding = 1,",
-        "    srcs = ['LibNoResourceFiles.java'],",
-        "    deps = ['//java/android/lib_with_resource_files'],",
-        ")");
-    scratch.file("java/android/lib_no_resource_files/LibNoResourceFiles.java",
-        "package android.lib_no_resource_files; public class LibNoResourceFiles {};");
-
-    scratch.file("java/android/binary/BUILD",
-        "android_binary(",
-        "    name = 'app',",
-        "    enable_data_binding = 1,",
-        "    manifest = 'AndroidManifest.xml',",
-        "    srcs = ['MyApp.java'],",
-        "    deps = ['//java/android/lib_no_resource_files'],",
-        ")");
-    scratch.file("java/android/binary/MyApp.java",
-        "package android.binary; public class MyApp {};");
-
+    writeDataBindingFilesWithNoResourcesDep();
     ConfiguredTarget ct = getConfiguredTarget("//java/android/binary:app");
     Set<Artifact> allArtifacts = actionsTestUtil().artifactClosureOf(getFilesToBuild(ct));
 
-    // Data binding resource processing outputs are expected only for libs with resources.
-    assertThat(getFirstArtifactEndingWith(allArtifacts,
-        "databinding/lib_no_resource_files/layout-info.zip")).isNull();
+    // Data binding resource processing outputs are expected for the app and libs with resources.
     assertThat(getFirstArtifactEndingWith(allArtifacts,
         "databinding/lib_with_resource_files/layout-info.zip")).isNotNull();
     assertThat(getFirstArtifactEndingWith(allArtifacts, "databinding/app/layout-info.zip"))
@@ -246,4 +247,30 @@ public class AndroidDataBindingTest extends AndroidBuildViewTestCase {
       assertThat(compileInput).doesNotMatch(".*lib_no_resource_files.*.bin");
     }
   }
+
+  @Test
+  public void libsWithNoResourcesOnlyRunAnnotationProcessor() throws Exception {
+    // Bazel skips resource processing because there are no new resources to process. But it still
+    // runs the annotation processor to ensure the Java compiler reads Java sources referenced by
+    // the deps' resources (e.g. "<variable type="some.package.SomeClass" />"). Without this,
+    // JavaBuilder's --reduce_classpath feature would strip out those sources as "unused" and fail
+    // the binary's compilation with unresolved symbol errors.
+    writeDataBindingFilesWithNoResourcesDep();
+    ConfiguredTarget ct = getConfiguredTarget("//java/android/lib_no_resource_files");
+    Iterable<Artifact> libArtifacts = getFilesToBuild(ct);
+
+    assertThat(getFirstArtifactEndingWith(libArtifacts, "_resources.jar")).isNull();
+    assertThat(getFirstArtifactEndingWith(libArtifacts, "layout-info.zip")).isNull();
+
+    JavaCompileAction libCompileAction = (JavaCompileAction) getGeneratingAction(
+        getFirstArtifactEndingWith(libArtifacts, "lib_no_resource_files.jar"));
+    // The annotation processor is attached to the Java compilation:
+    assertThat(getParamFileContents(libCompileAction)).containsAllOf(
+        "--processors",
+        "android.databinding.annotationprocessor.ProcessDataBinding");
+    // The dummy .java file with annotations that trigger the annotation process is present:
+    assertThat(ActionsTestUtil.prettyArtifactNames(libCompileAction.getInputs()))
+        .contains("java/android/lib_no_resource_files/databinding/lib_no_resource_files/"
+            + "DataBindingInfo.java");
+  }
 }