fix: (Javac) Executable#getGenericParameterTypes is broken.

teletha · Apr 23, 2024 · f576a0a · f576a0a
1 parent 20347ff
commit f576a0a
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Showing 3 changed files with 38 additions and 4 deletions.
diff --git a/src/main/java/reincarnation/LocalVariables.java b/src/main/java/reincarnation/LocalVariables.java
@@ -9,7 +9,7 @@
  */
 package reincarnation;
 
-import static reincarnation.OperandUtil.load;
+import static reincarnation.OperandUtil.*;
 
 import java.lang.reflect.Executable;
 import java.lang.reflect.Parameter;
@@ -21,6 +21,7 @@
 import java.util.Set;
 
 import reincarnation.coder.Naming;
+import reincarnation.util.Classes;
 
 /**
  * Local variable manager.
@@ -53,11 +54,12 @@ final class LocalVariables implements Naming {
         int offset = 0;
 
         if (isStatic == false) {
-            params.put(offset++, new OperandLocalVariable(clazz, 0, "this"));
+            params.put(offset, new OperandLocalVariable(clazz, offset, "this"));
+            offset++;
         }
 
         if (exe != null) {
-            Type[] types = exe.getGenericParameterTypes();
+            Type[] types = Classes.fixGenericParameterTypes(exe);
             Parameter[] parameters = exe.getParameters();
 
             for (int i = 0; i < types.length; i++) {

diff --git a/src/main/java/reincarnation/coder/java/JavaCoder.java b/src/main/java/reincarnation/coder/java/JavaCoder.java
@@ -403,7 +403,7 @@ private void writeLocalClass(Class clazz) {
      */
     private Join buildParameter(Executable executable, Naming strategy) {
         List<Ⅱ<Parameter, Type>> params = I.signal(executable.getParameters())
-                .combine(I.signal(executable.getGenericParameterTypes()))
+                .combine(I.signal(Classes.fixGenericParameterTypes(executable)))
                 .toList();
 
         return Join.of(params)

diff --git a/src/main/java/reincarnation/util/Classes.java b/src/main/java/reincarnation/util/Classes.java
@@ -9,10 +9,13 @@
  */
 package reincarnation.util;
 
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Executable;
 import java.lang.reflect.Member;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.lang.reflect.Parameter;
+import java.lang.reflect.Type;
 import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.Set;
@@ -201,4 +204,33 @@ public static boolean isWrapper(Method method) {
                 || (type == Short.class && name.equals("valueOf")) // for short
                 || (type == Character.class && name.equals("valueOf")); // for char
     }
+
+    /**
+     * Calling Executable#getGenericParameterTypes in class files compiled with Javac and ECJ
+     * returns different results for some APIs. (Enum constructors only?).
+     * 
+     * It seems to be caused by whether the parameter qualifier is Synthetic or Mandated, but I
+     * don't know the details.
+     * 
+     * @param executable
+     * @return
+     */
+    public static Type[] fixGenericParameterTypes(Executable executable) {
+        Class<?> clazz = executable.getDeclaringClass();
+        if (clazz.isEnum() && Constructor.class.isInstance(executable)) {
+            Type[] types = executable.getGenericParameterTypes();
+            Class<?>[] params = executable.getParameterTypes();
+
+            if (types.length < params.length) {
+                Type[] fixed = new Type[params.length];
+                System.arraycopy(types, 0, fixed, params.length - types.length, types.length);
+                fixed[0] = String.class; // enum name
+                fixed[1] = int.class; // enum ordinal
+
+                return fixed;
+            }
+        }
+
+        return executable.getGenericParameterTypes();
+    }
 }