Fix pruning of annotation declaration fields

Fields in annotation declarations are implicitly final, so are candidates for
constant variables.

--
MOS_MIGRATED_REVID=114878247

3 files changed, 71 insertions, 0 deletions

diff --git a/src/java_tools/buildjar/java/com/google/devtools/build/java/turbine/javac/TreePruner.java b/src/java_tools/buildjar/java/com/google/devtools/build/java/turbine/javac/TreePruner.java
index 092b82b9ba..ec4cbf5b37 100644
--- a/src/java_tools/buildjar/java/com/google/devtools/build/java/turbine/javac/TreePruner.java
+++ b/src/java_tools/buildjar/java/com/google/devtools/build/java/turbine/javac/TreePruner.java
@@ -29,6 +29,7 @@ import com.sun.source.util.SimpleTreeVisitor;
 import com.sun.tools.javac.code.Flags;
 import com.sun.tools.javac.tree.JCTree;
 import com.sun.tools.javac.tree.JCTree.JCBlock;
+import com.sun.tools.javac.tree.JCTree.JCClassDecl;
 import com.sun.tools.javac.tree.JCTree.JCExpression;
 import com.sun.tools.javac.tree.JCTree.JCExpressionStatement;
 import com.sun.tools.javac.tree.JCTree.JCIdent;
@@ -68,6 +69,17 @@ public class TreePruner {
       new TreeScanner() {
 
         @Override
+        public void visitClassDef(JCClassDecl tree) {
+          if ((tree.mods.flags & Flags.ANNOTATION) == Flags.ANNOTATION) {
+            // Fields in annotation declarations are implicitly final.
+            // Field initializers that are definitely not constant expressions could still be
+            // pruned, but we currently don't bother.
+            return;
+          }
+          super.visitClassDef(tree);
+        }
+
+        @Override
         public void visitMethodDef(JCMethodDecl tree) {
           if (tree.body == null) {
             return;
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 c01f5d0f0b..c9d49e08ee 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
@@ -861,4 +861,41 @@ public class JavacTurbineTest {
     };
     assertThat(text).isEqualTo(Joiner.on('\n').join(expected));
   }
+
+  @Test
+  public void annotationDeclaration() throws Exception {
+    addSourceLines(
+        "Anno.java",
+        "import java.lang.annotation.Retention;",
+        "import java.lang.annotation.RetentionPolicy;",
+        "@Retention(RetentionPolicy.RUNTIME)",
+        "@interface Anno {",
+        "  public int value() default CONST;",
+        "  int CONST = 42;",
+        "  int NONCONST = new Integer(42);",
+        "}");
+    addSourceLines("Hello.java", "@Anno(value=Anno.CONST)", "class Hello {", "}");
+
+    compile();
+
+    Map<String, byte[]> outputs = collectOutputs();
+
+    assertThat(outputs.keySet()).containsExactly("Anno.class", "Hello.class");
+
+    String text = textify(outputs.get("Hello.class"));
+    String[] expected = {
+      "// class version 51.0 (51)",
+      "// access flags 0x20",
+      "class Hello {",
+      "",
+      "",
+      "  @LAnno;(value=42)",
+      "",
+      "  // access flags 0x0",
+      "  <init>()V",
+      "}",
+      ""
+    };
+    assertThat(text).isEqualTo(Joiner.on('\n').join(expected));
+  }
 }
diff --git a/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/TreePrunerTest.java b/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/TreePrunerTest.java
index 711b5524cf..ccf0e33ba0 100644
--- a/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/TreePrunerTest.java
+++ b/src/java_tools/buildjar/javatests/com/google/devtools/build/java/turbine/javac/TreePrunerTest.java
@@ -261,6 +261,28 @@ public class TreePrunerTest {
     assertThat(prettyPrint(tree)).isEqualTo(Joiner.on('\n').join(expected));
   }
 
+  @Test
+  public void annotationDeclaration() {
+    String[] lines = {
+      "@interface Anno {",
+      "  int f() default CONST;",
+      "  int CONST = 42;",
+      "  int NONCONST = new Integer(42);",
+      "}",
+    };
+    JCCompilationUnit tree = parseLines(lines);
+    TreePruner.prune(tree);
+    String[] expected = {
+      "@interface Anno {",
+      "    ",
+      "    int f() default CONST;",
+      "    int CONST = 42;",
+      "    int NONCONST = new Integer(42);",
+      "}",
+    };
+    assertThat(prettyPrint(tree)).isEqualTo(Joiner.on('\n').join(expected));
+  }
+
   private String prettyPrint(JCCompilationUnit tree) {
     return tree.toString().trim();
   }