Don't copy lambda bodies from interfaces into implementing classes.

RELNOTES: none

PiperOrigin-RevId: 154452158

1 files changed, 16 insertions, 6 deletions

diff --git a/src/tools/android/java/com/google/devtools/build/android/desugar/DefaultMethodClassFixer.java b/src/tools/android/java/com/google/devtools/build/android/desugar/DefaultMethodClassFixer.java
index 8ad5dc285b..732f064bf5 100644
--- a/src/tools/android/java/com/google/devtools/build/android/desugar/DefaultMethodClassFixer.java
+++ b/src/tools/android/java/com/google/devtools/build/android/desugar/DefaultMethodClassFixer.java
@@ -132,6 +132,19 @@ public class DefaultMethodClassFixer extends ClassVisitor {
     return false;
   }
 
+  /**
+   * Returns {@code true} for non-bridge default methods not in {@link #instanceMethods}.
+   */
+  private boolean shouldStub(int access, String name, String desc) {
+    // Ignore private methods, which technically aren't default methods and can only be called from
+    // other methods defined in the interface.  This also ignores lambda body methods, which is fine
+    // as we don't want or need to stub those.  Also ignore bridge methods as javac adds them to
+    // concrete classes as needed anyway and we handle them separately for generated lambda classes.
+    return BitFlags.noneSet(access,
+            Opcodes.ACC_ABSTRACT | Opcodes.ACC_STATIC | Opcodes.ACC_BRIDGE | Opcodes.ACC_PRIVATE)
+        && !instanceMethods.contains(name + ":" + desc);
+  }
+
   private void stubMissingDefaultMethods(ImmutableList<String> interfaces) {
     for (String implemented : interfaces) {
       if (!seenInterfaces.add(implemented)) {
@@ -183,12 +196,10 @@ public class DefaultMethodClassFixer extends ClassVisitor {
     @Override
     public MethodVisitor visitMethod(
         int access, String name, String desc, String signature, String[] exceptions) {
-      if (BitFlags.noneSet(access, Opcodes.ACC_ABSTRACT | Opcodes.ACC_STATIC | Opcodes.ACC_BRIDGE)
-          && !instanceMethods.contains(name + ":" + desc)) {
+      if (shouldStub(access, name, desc)) {
         // Add this method to the class we're desugaring and stub in a body to call the default
         // implementation in the interface's companion class. ijar omits these methods when setting
-        // ACC_SYNTHETIC modifier, so don't. Don't do this for bridge methods, which we handle
-        // separately.
+        // ACC_SYNTHETIC modifier, so don't.
         // Signatures can be wrong, e.g., when type variables are introduced, instantiated, or
         // refined in the class we're processing, so drop them.
         MethodVisitor stubMethod =
@@ -255,8 +266,7 @@ public class DefaultMethodClassFixer extends ClassVisitor {
     @Override
     public MethodVisitor visitMethod(
         int access, String name, String desc, String signature, String[] exceptions) {
-      if (BitFlags.noneSet(access, Opcodes.ACC_ABSTRACT | Opcodes.ACC_STATIC | Opcodes.ACC_BRIDGE)
-          && !instanceMethods.contains(name + ":" + desc)) {
+      if (!found && shouldStub(access, name, desc)) {
         // Found a default method we're not ignoring (instanceMethods at this point contains methods
         // the top-level visited class implements itself).
         found = true;