Intresting

tools/java/BaseVehicleConstraintPatch.java

@@ -7,6 +7,7 @@ import org.objectweb.asm.tree.AbstractInsnNode;
 import org.objectweb.asm.tree.ClassNode;
 import org.objectweb.asm.tree.InsnNode;
 import org.objectweb.asm.tree.InsnList;
+import org.objectweb.asm.tree.LdcInsnNode;
 import org.objectweb.asm.tree.MethodInsnNode;
 import org.objectweb.asm.tree.MethodNode;
 import org.objectweb.asm.Opcodes;
@@ -17,6 +18,9 @@ import org.objectweb.asm.Opcodes;
  */
 public final class BaseVehicleConstraintPatch {
     private static final String TARGET_NAME = "addPointConstraint";
+    private static final String CLINIT_NAME = "<clinit>";
+    private static final String VOID_NOARG_DESC = "()V";
+    private static final String PATCH_LOG_LINE = "[Landtrain][BaseVehiclePatch] BaseVehicle override enabled";
     private static final String BREAK_DESC_OBJECT_BOOL = "(ZLjava/lang/Boolean;)V";
     private static final String BREAK_DESC_PRIMITIVE_BOOL = "(ZZ)V";
     private static final String BASE_VEHICLE_OWNER = "zombie/vehicles/BaseVehicle";
@@ -55,13 +59,19 @@ public final class BaseVehicleConstraintPatch {
                             + inspectedAddPointMethods
                             + ")");
         }
+        if (!ensureClassInitLog(classNode)) {
+            throw new IllegalStateException("Failed to inject BaseVehicle class-init debug log");
+        }
 
         ClassWriter writer = new ClassWriter(0);
         classNode.accept(writer);
 
         Files.createDirectories(output.getParent());
         Files.write(output, writer.toByteArray());
-        System.out.println("Patched BaseVehicle.class; removed breakConstraint calls: " + removedCalls);
+        System.out.println(
+                "Patched BaseVehicle.class; removed breakConstraint calls: "
+                        + removedCalls
+                        + ", class-init debug log: enabled");
     }
 
     private static boolean isTargetAddPointConstraint(String methodDesc) {
@@ -102,4 +112,72 @@ public final class BaseVehicleConstraintPatch {
 
         return patched;
     }
+
+    private static boolean ensureClassInitLog(ClassNode classNode) {
+        MethodNode clinit = null;
+        for (MethodNode method : classNode.methods) {
+            if (CLINIT_NAME.equals(method.name) && VOID_NOARG_DESC.equals(method.desc)) {
+                clinit = method;
+                break;
+            }
+        }
+
+        if (clinit == null) {
+            clinit = new MethodNode(Opcodes.ACC_STATIC, CLINIT_NAME, VOID_NOARG_DESC, null, null);
+            clinit.instructions = new InsnList();
+            clinit.instructions.add(createPatchLogInstructions());
+            clinit.instructions.add(new InsnNode(Opcodes.RETURN));
+            clinit.maxStack = 2;
+            clinit.maxLocals = 0;
+            classNode.methods.add(clinit);
+            return true;
+        }
+
+        if (hasPatchLog(clinit)) {
+            return true;
+        }
+
+        boolean inserted = false;
+        for (AbstractInsnNode node = clinit.instructions.getFirst(); node != null; ) {
+            AbstractInsnNode next = node.getNext();
+            if (node.getOpcode() == Opcodes.RETURN) {
+                clinit.instructions.insertBefore(node, createPatchLogInstructions());
+                inserted = true;
+            }
+            node = next;
+        }
+
+        if (inserted) {
+            clinit.maxStack = Math.max(clinit.maxStack, 2);
+        }
+        return inserted;
+    }
+
+    private static boolean hasPatchLog(MethodNode method) {
+        for (AbstractInsnNode node = method.instructions.getFirst(); node != null; node = node.getNext()) {
+            if (node instanceof LdcInsnNode ldc
+                    && ldc.cst instanceof String text
+                    && PATCH_LOG_LINE.equals(text)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private static InsnList createPatchLogInstructions() {
+        InsnList insns = new InsnList();
+        insns.add(new org.objectweb.asm.tree.FieldInsnNode(
+                Opcodes.GETSTATIC,
+                "java/lang/System",
+                "out",
+                "Ljava/io/PrintStream;"));
+        insns.add(new LdcInsnNode(PATCH_LOG_LINE));
+        insns.add(new MethodInsnNode(
+                Opcodes.INVOKEVIRTUAL,
+                "java/io/PrintStream",
+                "println",
+                "(Ljava/lang/String;)V",
+                false));
+        return insns;
+    }
 }