Avoid propagating an exception to the compiler if we fail to load Aut…

…oValue extensions due to a corrupt jar file in the class path.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=129374653

value/src/main/java/com/google/auto/value/processor/AutoValueProcessor.java

@@ -39,7 +39,6 @@
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Sets;
-
 import java.beans.Introspector;
 import java.io.IOException;
 import java.io.Serializable;
@@ -52,10 +51,10 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.ServiceConfigurationError;
 import java.util.ServiceLoader;
 import java.util.Set;
 import java.util.regex.Pattern;
-
 import javax.annotation.Generated;
 import javax.annotation.processing.AbstractProcessor;
 import javax.annotation.processing.ProcessingEnvironment;
@@ -93,12 +92,19 @@
 @AutoService(Processor.class)
 public class AutoValueProcessor extends AbstractProcessor {
   public AutoValueProcessor() {
-    this(ServiceLoader.load(AutoValueExtension.class, AutoValueProcessor.class.getClassLoader()));
+    this(AutoValueProcessor.class.getClassLoader());
+  }
+
+  @VisibleForTesting
+  AutoValueProcessor(ClassLoader loaderForExtensions) {
+    this.extensions = null;
+    this.loaderForExtensions = loaderForExtensions;
   }
 
   @VisibleForTesting
   public AutoValueProcessor(Iterable<? extends AutoValueExtension> extensions) {
-    this.extensions = extensions;
+    this.extensions = ImmutableList.<AutoValueExtension>copyOf(extensions);
+    this.loaderForExtensions = null;
   }
 
   @Override
@@ -126,7 +132,11 @@ public SourceVersion getSupportedSourceVersion() {
    */
   private final List<String> deferredTypeNames = new ArrayList<String>();
 
-  private Iterable<? extends AutoValueExtension> extensions;
+  // Depending on how this AutoValueProcessor was constructed, we might already have a list of
+  // extensions when init() is run, or, if `extensions` is null, we have a ClassLoader that will be
+  // used to get the list using the ServiceLoader API.
+  private ImmutableList<AutoValueExtension> extensions;
+  private final ClassLoader loaderForExtensions;
 
   private Types typeUtils;
 
@@ -135,6 +145,26 @@ public synchronized void init(ProcessingEnvironment processingEnv) {
     super.init(processingEnv);
     errorReporter = new ErrorReporter(processingEnv);
     typeUtils = processingEnv.getTypeUtils();
+
+    if (extensions == null) {
+      try {
+        extensions = ImmutableList.copyOf(
+            ServiceLoader.load(AutoValueExtension.class, loaderForExtensions));
+        // ServiceLoader.load returns a lazily-evaluated Iterable, so evaluate it eagerly now
+        // to discover any exceptions.
+      } catch (Throwable t) {
+        StringBuilder warning = new StringBuilder();
+        warning.append(
+            "An exception occurred while looking for AutoValue extensions. "
+                + "No extensions will function.");
+        if (t instanceof ServiceConfigurationError) {
+          warning.append(" This may be due to a corrupt jar file in the compiler's classpath.");
+        }
+        warning.append(" Exception: ").append(t);
+        errorReporter.reportWarning(warning.toString(), null);
+        extensions = ImmutableList.of();
+      }
+    }
   }
 
   @Override

value/src/test/java/com/google/auto/value/processor/ExtensionTest.java

@@ -22,21 +22,28 @@
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.truth.Truth;
+import com.google.testing.compile.CompileTester.SuccessfulCompilationClause;
 import com.google.testing.compile.JavaFileObjects;
-
-import junit.framework.TestCase;
-
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.net.URL;
+import java.net.URLClassLoader;
 import java.util.Collections;
 import java.util.Map;
+import java.util.ServiceConfigurationError;
 import java.util.Set;
-
+import java.util.jar.JarOutputStream;
+import java.util.zip.ZipEntry;
 import javax.lang.model.element.ExecutableElement;
 import javax.lang.model.element.TypeElement;
 import javax.lang.model.element.VariableElement;
 import javax.lang.model.type.TypeKind;
 import javax.lang.model.util.ElementFilter;
 import javax.lang.model.util.Elements;
 import javax.tools.JavaFileObject;
+import javax.tools.StandardLocation;
+import junit.framework.TestCase;
 
 public class ExtensionTest extends TestCase {
   public void testExtensionCompilation() throws Exception {
@@ -463,6 +470,50 @@ public void testUnconsumedMethod() throws Exception {
     // so we know what to expect.
   }
 
+  /**
+   * Tests that the search for extensions doesn't completely blow AutoValue up if there is a
+   * corrupt jar in the {@code processorpath}. If we're not careful, that can lead to a
+   * ServiceConfigurationError.
+   */
+  public void testBadJarDoesntBlowUp() throws IOException {
+    File badJar = File.createTempFile("bogus", ".jar");
+    try {
+      doTestBadJarDoesntBlowUp(badJar);
+    } finally {
+      badJar.delete();
+    }
+  }
+
+  private void doTestBadJarDoesntBlowUp(File badJar) throws IOException {
+    FileOutputStream fileOutputStream = new FileOutputStream(badJar);
+    JarOutputStream jarOutputStream = new JarOutputStream(fileOutputStream);
+    byte[] bogusLine = "bogus line\n".getBytes("UTF-8");
+    ZipEntry zipEntry = new ZipEntry("META-INF/services/" + AutoValueExtension.class.getName());
+    zipEntry.setSize(bogusLine.length);
+    jarOutputStream.putNextEntry(zipEntry);
+    jarOutputStream.write(bogusLine);
+    jarOutputStream.close();
+    ClassLoader badJarLoader = new URLClassLoader(new URL[] {badJar.toURI().toURL()});
+    JavaFileObject javaFileObject = JavaFileObjects.forSourceLines(
+        "foo.bar.Baz",
+        "package foo.bar;",
+        "",
+        "import com.google.auto.value.AutoValue;",
+        "",
+        "@AutoValue",
+        "public abstract class Baz {",
+        "}");
+    SuccessfulCompilationClause success = assertThat(javaFileObject)
+        .withCompilerOptions("-Xlint:-processing")
+        .processedWith(new AutoValueProcessor(badJarLoader))
+        .compilesWithoutError();
+    success.withWarningContaining(
+        "This may be due to a corrupt jar file in the compiler's classpath. Exception: "
+            + ServiceConfigurationError.class.getName());
+    success.and()
+        .generatesFileNamed(StandardLocation.SOURCE_OUTPUT, "foo.bar", "AutoValue_Baz.java");
+  }
+
   private static class FooExtension extends AutoValueExtension {
 
     @Override