Track which output files are written

instead of initializing all file objects to empty. Some annotation processors
speculatively open files and handle FileNotFoundException, and we were always
providing empty files.

--
MOS_MIGRATED_REVID=118730162

3 files changed, 55 insertions, 2 deletions

diff --git a/src/java_tools/buildjar/java/com/google/devtools/build/java/turbine/javac/JavacTurbine.java b/src/java_tools/buildjar/java/com/google/devtools/build/java/turbine/javac/JavacTurbine.java
index a3f8d7265b..df446cd300 100644
--- a/src/java_tools/buildjar/java/com/google/devtools/build/java/turbine/javac/JavacTurbine.java
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/java/turbine/javac/JavacTurbine.java
@@ -248,6 +248,9 @@ public class JavacTurbine implements AutoCloseable {
         }
         String name = entry.getKey();
         byte[] bytes = entry.getValue().asBytes();
+        if (bytes == null) {
+          continue;
+        }
         if (name.endsWith(".class")) {
           bytes = processBytecode(bytes);
         }
diff --git a/src/java_tools/buildjar/java/com/google/devtools/build/java/turbine/javac/ZipOutputFileManager.java b/src/java_tools/buildjar/java/com/google/devtools/build/java/turbine/javac/ZipOutputFileManager.java
index cb197a487b..42d698e7d8 100644
--- a/src/java_tools/buildjar/java/com/google/devtools/build/java/turbine/javac/ZipOutputFileManager.java
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/java/turbine/javac/ZipOutputFileManager.java
@@ -20,6 +20,7 @@ import com.sun.tools.javac.util.Context;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -32,6 +33,7 @@ import java.nio.charset.CodingErrorAction;
 import java.nio.charset.StandardCharsets;
 import java.util.Map;
 
+import javax.annotation.Nullable;
 import javax.tools.FileObject;
 import javax.tools.JavaFileManager;
 import javax.tools.JavaFileObject;
@@ -116,7 +118,7 @@ public class ZipOutputFileManager extends JavacFileManager {
 
     public final Location location;
 
-    private final ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+    @Nullable private ByteArrayOutputStream buffer;
 
     public OutputFileObject(String name, Kind kind, Location location) {
       super(URI.create("outputbuffer:/" + name), kind);
@@ -125,16 +127,25 @@ public class ZipOutputFileManager extends JavacFileManager {
 
     @Override
     public OutputStream openOutputStream() {
+      if (buffer == null) {
+        buffer = new ByteArrayOutputStream();
+      }
       return buffer;
     }
 
     @Override
     public InputStream openInputStream() throws IOException {
+      if (buffer == null) {
+        throw new FileNotFoundException(getName());
+      }
       return new ByteArrayInputStream(asBytes());
     }
 
     @Override
     public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {
+      if (buffer == null) {
+        throw new FileNotFoundException(getName());
+      }
       CodingErrorAction errorAction =
           ignoreEncodingErrors ? CodingErrorAction.IGNORE : CodingErrorAction.REPORT;
       CharsetDecoder decoder =
@@ -146,7 +157,7 @@ public class ZipOutputFileManager extends JavacFileManager {
     }
 
     public byte[] asBytes() {
-      return buffer.toByteArray();
+      return buffer != null ? buffer.toByteArray() : null;
     }
   }
 
diff --git a/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/JavacTurbineTest.java b/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/JavacTurbineTest.java
index 015a12212b..7588d647ec 100644
--- a/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/JavacTurbineTest.java
+++ b/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/JavacTurbineTest.java
@@ -1042,4 +1042,43 @@ public class JavacTurbineTest {
     }
     assertThat(errOutput.toString()).contains("invalid flag: -NOT_AN_OPTION");
   }
+
+  /** An annotation processor that reads a file that doesn't exist. */
+  @SupportedAnnotationTypes("*")
+  public static class NoSuchFileProcessor extends AbstractProcessor {
+
+    @Override
+    public SourceVersion getSupportedSourceVersion() {
+      return SourceVersion.latest();
+    }
+
+    @Override
+    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
+      try {
+        processingEnv
+            .getFiler()
+            .getResource(StandardLocation.CLASS_OUTPUT, "", "NO_SUCH_FILE")
+            .openInputStream();
+      } catch (IOException e) {
+        throw new IOError(e);
+      }
+      return false;
+    }
+  }
+
+  @Test
+  public void processorReadsNonexistantFile() throws Exception {
+    addSourceLines("Hello.java", "@Deprecated class Hello {}");
+    optionsBuilder.setProcessors(ImmutableList.of(NoSuchFileProcessor.class.getName()));
+    optionsBuilder.addProcessorPathEntries(
+        ImmutableList.copyOf(Splitter.on(':').split(System.getProperty("java.class.path"))));
+    optionsBuilder.addSources(ImmutableList.copyOf(Iterables.transform(sources, TO_STRING)));
+
+    StringWriter errOutput = new StringWriter();
+    try (JavacTurbine turbine =
+        new JavacTurbine(new PrintWriter(errOutput, true), optionsBuilder.build())) {
+      assertThat(turbine.compile()).isEqualTo(Result.ERROR);
+    }
+    assertThat(errOutput.toString()).contains("FileNotFoundException: /NO_SUCH_FILE");
+  }
 }