Fix bug where testing a package-info.java file with parsesAs() threw an NPE.

netdpb · Compile-Testing Team · commit c46b1b68bfe9 · 2021-05-24T13:11:07.000-07:00
Fixes #85. RELNOTES=Fixed bug where testing `package-info.java` with `parsesAs()` threw an NPE. PiperOrigin-RevId: 375541051
diff --git a/src/main/java/com/google/testing/compile/TypeEnumerator.java b/src/main/java/com/google/testing/compile/TypeEnumerator.java
@@ -21,15 +21,13 @@
 import com.google.common.collect.FluentIterable;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Sets;
-
 import com.sun.source.tree.ClassTree;
 import com.sun.source.tree.CompilationUnitTree;
 import com.sun.source.tree.ExpressionStatementTree;
 import com.sun.source.tree.IdentifierTree;
 import com.sun.source.tree.MemberSelectTree;
 import com.sun.source.tree.Tree;
 import com.sun.source.util.TreeScanner;
-
 import java.util.Set;
 
 /**
@@ -100,7 +98,7 @@ public Set<String> visitCompilationUnit(CompilationUnitTree reference, Void v) {
             "package identifier. Found " + packageSet);
       }
       final String packageName = packageSet.isEmpty() ? "" : packageSet.iterator().next();
-      Set<String> typeDeclSet = scan(reference.getTypeDecls(), v);
+      Set<String> typeDeclSet = firstNonNull(scan(reference.getTypeDecls(), v), ImmutableSet.of());
       return FluentIterable.from(typeDeclSet)
           .transform(new Function<String, String>() {
             @Override public String apply(String typeName) {
diff --git a/src/test/java/com/google/testing/compile/CompilationSubjectTest.java b/src/test/java/com/google/testing/compile/CompilationSubjectTest.java
@@ -808,6 +808,16 @@ public void generatedSourceFile() {
                   GeneratingProcessor.GENERATED_CLASS_NAME, GeneratingProcessor.GENERATED_SOURCE));
     }
 
+    @Test
+    public void generatedSourceFile_packageInfo() {
+      GeneratingProcessor generatingProcessor = new GeneratingProcessor("test");
+      assertThat(javac().withProcessors(generatingProcessor).compile(HELLO_WORLD_RESOURCE))
+          .generatedSourceFile("test.package-info")
+          .hasSourceEquivalentTo(
+              JavaFileObjects.forSourceString(
+                  "test.package-info", generatingProcessor.generatedPackageInfoSource()));
+    }
+
     @Test
     public void generatedSourceFile_fail() {
       expectFailure
diff --git a/src/test/java/com/google/testing/compile/GeneratingProcessor.java b/src/test/java/com/google/testing/compile/GeneratingProcessor.java
@@ -21,6 +21,7 @@
 import com.google.common.collect.ImmutableSet;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import java.io.IOException;
+import java.io.UncheckedIOException;
 import java.io.Writer;
 import java.util.Set;
 import javax.annotation.processing.AbstractProcessor;
@@ -29,6 +30,7 @@
 import javax.annotation.processing.RoundEnvironment;
 import javax.lang.model.SourceVersion;
 import javax.lang.model.element.TypeElement;
+import javax.tools.FileObject;
 
 final class GeneratingProcessor extends AbstractProcessor {
   static final String GENERATED_CLASS_NAME = "Blah";
@@ -50,31 +52,33 @@ final class GeneratingProcessor extends AbstractProcessor {
   @Override
   public synchronized void init(ProcessingEnvironment processingEnv) {
     Filer filer = processingEnv.getFiler();
-    try (Writer writer = filer.createSourceFile(generatedClassName()).openWriter()) {
-      writer.write(GENERATED_SOURCE);
-    } catch (IOException e) {
-      throw new RuntimeException(e);
-    }
+    try {
+      write(filer.createSourceFile(generatedClassName()), GENERATED_SOURCE);
+      write(
+          filer.createResource(
+              CLASS_OUTPUT, getClass().getPackage().getName(), GENERATED_RESOURCE_NAME),
+          GENERATED_RESOURCE);
 
-    try (Writer writer =
-        filer
-            .createResource(
-                CLASS_OUTPUT, getClass().getPackage().getName(), GENERATED_RESOURCE_NAME)
-            .openWriter()) {
-      writer.write(GENERATED_RESOURCE);
+      if (!packageName.isEmpty()) {
+        write(filer.createSourceFile(packageName + ".package-info"), generatedPackageInfoSource());
+      }
     } catch (IOException e) {
-      throw new RuntimeException(e);
+      throw new UncheckedIOException(e);
     }
   }
 
   String packageName() {
     return packageName;
   }
-  
+
   String generatedClassName() {
     return packageName.isEmpty() ? GENERATED_CLASS_NAME : packageName + "." + GENERATED_CLASS_NAME;
   }
 
+  String generatedPackageInfoSource() {
+    return "package " + packageName + ";\n";
+  }
+
   @CanIgnoreReturnValue
   @Override
   public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
@@ -90,4 +94,10 @@ public Set<String> getSupportedAnnotationTypes() {
   public SourceVersion getSupportedSourceVersion() {
     return SourceVersion.latestSupported();
   }
+
+  private static void write(FileObject file, String contents) throws IOException {
+    try (Writer writer = file.openWriter()) {
+      writer.write(contents);
+    }
+  }
 }
diff --git a/src/test/java/com/google/testing/compile/JavaSourcesSubjectFactoryTest.java b/src/test/java/com/google/testing/compile/JavaSourcesSubjectFactoryTest.java
@@ -741,6 +741,19 @@ public void generatesSources() {
                 GeneratingProcessor.GENERATED_CLASS_NAME, GeneratingProcessor.GENERATED_SOURCE));
   }
 
+  @Test
+  public void generatesSources_packageInfo() {
+    GeneratingProcessor generatingProcessor = new GeneratingProcessor("test.generated");
+    assertAbout(javaSource())
+        .that(HELLO_WORLD_RESOURCE)
+        .processedWith(generatingProcessor)
+        .compilesWithoutError()
+        .and()
+        .generatesSources(
+            JavaFileObjects.forSourceString(
+                "test.generated.package-info", generatingProcessor.generatedPackageInfoSource()));
+  }
+
   @Test
   public void generatesSources_failOnUnexpected() {
     String failingExpectationSource = "abstract class Blah {}";
