Handles missing classes.jar in aar_import gracefully, by creating an empty jar file instead of crashing Bazel.

--
MOS_MIGRATED_REVID=135405636

6 files changed, 152 insertions, 8 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/android/AarImport.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/android/AarImport.java
index 8803d86b8d..5b3b7f778e 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/android/AarImport.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/android/AarImport.java
@@ -62,19 +62,20 @@ public class AarImport implements RuleConfiguredTargetFactory {
     // classes.jar is required in every AAR.
     Artifact classesJar = createAarArtifact(ruleContext, CLASSES_JAR);
     ruleContext.registerAction(
-        createSingleFileExtractor(ruleContext, aar, CLASSES_JAR, classesJar));
+        createEmbeddedJarExtractorActions(ruleContext, aar, CLASSES_JAR, classesJar));
 
     // AndroidManifest.xml is required in every AAR.
     Artifact androidManifestArtifact = createAarArtifact(ruleContext, ANDROID_MANIFEST);
-    ruleContext.registerAction(
-        createSingleFileExtractor(ruleContext, aar, ANDROID_MANIFEST, androidManifestArtifact));
+    ruleContext.registerAction(createSingleFileExtractorActions(
+        ruleContext, aar, ANDROID_MANIFEST, androidManifestArtifact));
 
     Artifact resourcesManifest = createAarArtifact(ruleContext, "resource_manifest");
     ruleContext.registerAction(
-        createManifestExtractor(ruleContext, aar, "res/.*", resourcesManifest));
+        createManifestExtractorActions(ruleContext, aar, "res/.*", resourcesManifest));
 
     Artifact resources = createResourcesTreeArtifact(ruleContext);
-    ruleContext.registerAction(createTreePopulater(ruleContext, aar, resourcesManifest, resources));
+    ruleContext.registerAction(
+        createTreePopulaterActions(ruleContext, aar, resourcesManifest, resources));
 
     ApplicationManifest androidManifest =
         ApplicationManifest.fromExplicitManifest(ruleContext, androidManifestArtifact);
@@ -114,7 +115,7 @@ public class AarImport implements RuleConfiguredTargetFactory {
         .build();
   }
 
-  private static Action[] createSingleFileExtractor(RuleContext ruleContext, Artifact aar,
+  private static Action[] createSingleFileExtractorActions(RuleContext ruleContext, Artifact aar,
       String filename, Artifact outputArtifact) {
     return new SpawnAction.Builder()
         .setExecutable(ruleContext.getExecutablePrerequisite("$zipper", Mode.HOST))
@@ -129,7 +130,24 @@ public class AarImport implements RuleConfiguredTargetFactory {
         .build(ruleContext);
   }
 
-  private static Action createTreePopulater(RuleContext ruleContext, Artifact aar,
+  // Extracts a jar file from the aar if it exists, otherwise outputs an empty jar file.
+  private static Action[] createEmbeddedJarExtractorActions(RuleContext ruleContext, Artifact aar,
+      String filename, Artifact outputArtifact) {
+    return new SpawnAction.Builder()
+        .setExecutable(ruleContext.getExecutablePrerequisite("$embedded_jar_extractor", Mode.HOST))
+        .setMnemonic("AarJarExtractor")
+        .setProgressMessage("Extracting " + filename + " from " + aar.getFilename())
+        .addArgument("--input_archive")
+        .addInputArgument(aar)
+        .addArgument("--filename")
+        .addArgument(filename)
+        .addArgument("--output_dir")
+        .addOutput(outputArtifact)
+        .addArgument(outputArtifact.getExecPath().getParentDirectory().getPathString())
+        .build(ruleContext);
+  }
+
+  private static Action createTreePopulaterActions(RuleContext ruleContext, Artifact aar,
       Artifact manifest, Artifact outputTree) {
     return new PopulateTreeArtifactAction(
         ruleContext.getActionOwner(),
@@ -139,7 +157,7 @@ public class AarImport implements RuleConfiguredTargetFactory {
         ruleContext.getExecutablePrerequisite("$zipper", Mode.HOST));
   }
 
-  private static Action[] createManifestExtractor(RuleContext ruleContext, Artifact aar,
+  private static Action[] createManifestExtractorActions(RuleContext ruleContext, Artifact aar,
       String filenameRegexp, Artifact manifest) {
     return new SpawnAction.Builder()
         .setExecutable(ruleContext.getExecutablePrerequisite("$zip_manifest_creator", Mode.HOST))
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/android/AarImportRule.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/android/AarImportRule.java
index 61618bdb6a..2d09378c12 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/android/AarImportRule.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/android/AarImportRule.java
@@ -43,6 +43,11 @@ public class AarImportRule implements RuleDefinition {
             .allowedRuleClasses("aar_import", "java_import")
             .allowedFileTypes()
             .validityPredicate(ANY_EDGE))
+        .add(attr("$embedded_jar_extractor", LABEL)
+            .cfg(HOST)
+            .exec()
+            .value(Label.parseAbsoluteUnchecked(
+                environment.getToolsRepository() + "//tools/zip:embedded_jar_extractor")))
         .add(attr("$zip_manifest_creator", LABEL)
             .cfg(HOST)
             .exec()
diff --git a/tools/zip/BUILD b/tools/zip/BUILD
index cfb986b993..4ccf9f7273 100644
--- a/tools/zip/BUILD
+++ b/tools/zip/BUILD
@@ -17,3 +17,15 @@ sh_test(
     srcs = ["zip_manifest_creator_test.sh"],
     data = [":zip_manifest_creator"],
 )
+
+py_binary(
+    name = "embedded_jar_extractor",
+    srcs = ["embedded_jar_extractor.py"],
+    deps = ["//third_party/py/gflags"],
+)
+
+py_test(
+    name = "embedded_jar_extractor_test",
+    srcs = ["embedded_jar_extractor_test.py"],
+    deps = [":embedded_jar_extractor"],
+)
diff --git a/tools/zip/BUILD.tools b/tools/zip/BUILD.tools
index 58f9267f2f..542ddce946 100644
--- a/tools/zip/BUILD.tools
+++ b/tools/zip/BUILD.tools
@@ -10,3 +10,9 @@ sh_binary(
     srcs = ["zip_manifest_creator.sh"],
     data = [":zipper"],
 )
+
+py_binary(
+    name = "embedded_jar_extractor",
+    srcs = ["embedded_jar_extractor.py"],
+    deps = ["//third_party/py/gflags"],
+)
diff --git a/tools/zip/embedded_jar_extractor.py b/tools/zip/embedded_jar_extractor.py
new file mode 100644
index 0000000000..1111b2993e
--- /dev/null
+++ b/tools/zip/embedded_jar_extractor.py
@@ -0,0 +1,53 @@
+# Copyright 2016 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""A tool for extracting a jar file from an archive and failing gracefully.
+
+If the jar file is present within the archive, it is extracted into the output
+directory. If not, an empty jar is created in the output directory.
+"""
+
+import os
+import sys
+import zipfile
+
+from third_party.py import gflags
+
+FLAGS = gflags.FLAGS
+
+gflags.DEFINE_string("input_archive", None, "Input archive")
+gflags.MarkFlagAsRequired("input_archive")
+gflags.DEFINE_string("filename", None, "Filename of JAR to extract")
+gflags.MarkFlagAsRequired("filename")
+gflags.DEFINE_string("output_dir", None, "Output directory")
+gflags.MarkFlagAsRequired("output_dir")
+
+
+def ExtractEmbeddedJar(input_archive, filename, output_dir):
+  with zipfile.ZipFile(input_archive, "r") as archive:
+    if filename in archive.namelist():
+      archive.extract(filename, output_dir)
+    else:
+      with zipfile.ZipFile(os.path.join(output_dir, filename), "w") as jar:
+        # All jar files must contain META-INF/MANIFEST.MF.
+        jar.writestr("META-INF/MANIFEST.MF", ("Manifest-Version: 1.0\n"
+                                              "Created-By: Bazel\n"))
+
+
+def main():
+  ExtractEmbeddedJar(FLAGS.input_archive, FLAGS.filename, FLAGS.output_dir)
+
+if __name__ == "__main__":
+  FLAGS(sys.argv)
+  main()
diff --git a/tools/zip/embedded_jar_extractor_test.py b/tools/zip/embedded_jar_extractor_test.py
new file mode 100644
index 0000000000..568e0b3366
--- /dev/null
+++ b/tools/zip/embedded_jar_extractor_test.py
@@ -0,0 +1,50 @@
+# Copyright 2016 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Tests for embedded_jar_extractor."""
+
+import filecmp
+import os
+import unittest
+import zipfile
+
+from tools.zip import embedded_jar_extractor
+
+
+class EmbeddedJarExtractorTest(unittest.TestCase):
+  """Unit tests for embedded_jar_extractor.py."""
+
+  def testPassingJarFile(self):
+    bjar = zipfile.ZipFile("b.jar", "w")
+    bjar.close()
+    azip = zipfile.ZipFile("a.zip", "w")
+    azip.write("b.jar")
+    azip.close()
+    if not os.path.exists("output"):
+      os.mkdir("output")
+    embedded_jar_extractor.ExtractEmbeddedJar("a.zip", "b.jar", "output")
+    self.assertTrue(filecmp.cmp("b.jar", "output/b.jar"))
+
+  def testMissingJarFile(self):
+    azip = zipfile.ZipFile("a.zip", "w")
+    azip.close()
+    if not os.path.exists("output"):
+      os.mkdir("output")
+    embedded_jar_extractor.ExtractEmbeddedJar("a.zip", "b.jar", "output")
+    bjar = zipfile.ZipFile("output/b.jar", "r")
+    self.assertEqual(["META-INF/MANIFEST.MF"], bjar.namelist())
+
+
+if __name__ == "__main__":
+  unittest.main()