external artifact builder: show warning instead of creating empty jar [rev by Dmitry A.]

jps/jps-builders/src/org/jetbrains/jps/incremental/artifacts/impl/JarsBuilder.java

@@ -135,9 +135,9 @@ public class JarsBuilder {
   }
 
   private void buildJar(final JarInfo jar) throws IOException {
+    final String emptyArchiveMessage = "Archive '" + jar.getPresentableDestination() + "' doesn't contain files so it won't be created";
     if (jar.getContent().isEmpty()) {
-      final String message = "Archive '" + jar.getPresentableDestination() + "' has no files so it won't be created";
-      myContext.processMessage(new CompilerMessage(IncArtifactBuilder.BUILDER_NAME, BuildMessage.Kind.WARNING, message));
+      myContext.processMessage(new CompilerMessage(IncArtifactBuilder.BUILDER_NAME, BuildMessage.Kind.WARNING, emptyArchiveMessage));
       return;
     }
 
@@ -151,8 +151,8 @@ public class JarsBuilder {
     Manifest manifest = loadManifest(jar, packedFilePaths);
     final JarOutputStream jarOutputStream = createJarOutputStream(jarFile, manifest);
 
+    final THashSet<String> writtenPaths = new THashSet<String>();
     try {
-      final THashSet<String> writtenPaths = new THashSet<String>();
       if (manifest != null) {
         writtenPaths.add(JarFile.MANIFEST_NAME);
       }
@@ -187,16 +187,31 @@ public class JarsBuilder {
         }
       }
 
+      if (writtenPaths.isEmpty()) {
+        myContext.processMessage(new CompilerMessage(IncArtifactBuilder.BUILDER_NAME, BuildMessage.Kind.WARNING, emptyArchiveMessage));
+        return;
+      }
+
       final ProjectBuilderLogger logger = myContext.getLoggingManager().getProjectBuilderLogger();
       if (logger.isEnabled()) {
-
         logger.logCompiledPaths(packedFilePaths, IncArtifactBuilder.BUILDER_NAME, "Packing files:");
       }
       myOutputConsumer.registerOutputFile(targetJarPath, packedFilePaths);
 
     }
     finally {
-      jarOutputStream.close();
+      if (writtenPaths.isEmpty()) {
+        try {
+          jarOutputStream.close();
+        }
+        catch (IOException ignored) {
+        }
+        FileUtil.delete(jarFile);
+        myBuiltJars.remove(jar);
+      }
+      else {
+        jarOutputStream.close();
+      }
     }
   }
 

jps/jps-builders/testSrc/org/jetbrains/jps/incremental/artifacts/ArtifactBuilderTest.java

@@ -303,6 +303,28 @@ public class ArtifactBuilderTest extends ArtifactBuilderTestCase {
     assertOutput(a, fs().archive("a.jar").file("a.txt").end().file("b.txt"));
   }
 
+  public void testDoNotCreateEmptyArchive() {
+    String file = createFile("dir/a.txt");
+    JpsArtifact a = addArtifact(archive("a.jar").parentDirCopy(file));
+    delete(file);
+    buildAll();
+    assertEmptyOutput(a);
+  }
+
+  public void testDoNotCreateEmptyArchiveInsideArchive() {
+    String file = createFile("dir/a.txt");
+    JpsArtifact a = addArtifact(archive("a.jar").archive("inner.jar").parentDirCopy(file));
+    delete(file);
+    buildAll();
+    assertEmptyOutput(a);
+  }
+
+  public void testDoNotCreateEmptyArchiveFromExtractedDirectory() {
+    final JpsArtifact a = addArtifact("a", archive("a.jar").dir("dir").extractedDir(getJUnitJarPath(), "/xxx/"));
+    buildAll();
+    assertEmptyOutput(a);
+  }
+
   private static void createFileInArtifactOutput(JpsArtifact a, final String fileName) throws IOException {
     assertTrue(new File(a.getOutputPath(), fileName).createNewFile());
   }

jps/jps-builders/testSrc/org/jetbrains/jps/incremental/artifacts/ArtifactBuilderTestCase.java

@@ -97,8 +97,8 @@ public abstract class ArtifactBuilderTestCase extends JpsBuildTestCase {
     return FileUtil.toSystemIndependentName(file.getAbsolutePath());
   }
 
-  protected static void assertEmptyOutput(JpsArtifact a1) {
-    assertOutput(a1, fs());
+  protected static void assertEmptyOutput(JpsArtifact a) {
+    assertOutput(a, fs());
   }
 
   protected void assertBuildFailed(JpsArtifact a) {