[JENKINS-67011] bridge-method-injector creates questionable bytecode (#34)

basil · web-flow · commit 95cee5b9756f · 2022-11-17T14:37:49.000-08:00
diff --git a/injector/src/main/java/com/infradna/tool/bridge_method_injector/MethodInjector.java b/injector/src/main/java/com/infradna/tool/bridge_method_injector/MethodInjector.java
@@ -77,29 +77,7 @@ public void handle(File classFile) throws IOException {
         byte[] image;
         try (FileInputStream in = new FileInputStream(classFile); BufferedInputStream bis = new BufferedInputStream(in)) {
             ClassReader cr = new ClassReader(bis);
-            /*
-                working around JENKINS-22525 by not passing in 'cr'
-
-                Javac as of 6u31 seems to produce duplicate constant pool entries in some cases.
-                When such a class is transformed through ClassReader -> ClassWriter, it creates
-                a class file where reference sites to those duplicate entries get reshuffled
-                (for example, say #15 and #30 are the duplicate entries, and after a transformation
-                some references that used to use #15 now refers to #30, and vice versa.)
-
-                This is because ClassVisitor interfaces passes around strings, and
-                ClassWriter looks up its constant pool to assign its index.
-
-                For whatever reasons, this triggers "incompatible InnerClasses attribute" problem
-                in IBM J9VM (observed with R26_Java726_SR7_20140409_1418_B195732), while
-                it is happy with the original class file.
-
-                It appears that this rare situation of having duplicate entries in constant pools
-                and have various references use them in a certain way induces this J9 VM bug.
-
-                To work around this problem, we make ASM rebuild the constant pool from scratch,
-                which totally eliminates any duplicate entries.
-             */
-            ClassWriter cw = new ClassWriter(/*cr,*/COMPUTE_MAXS);
+            ClassWriter cw = new ClassWriter(cr,COMPUTE_MAXS);
             cr.accept(new Transformer(new ClassAnnotationInjectorImpl(cw)),0);
             image = cw.toByteArray();
         } catch (AlreadyUpToDate unused) {
