From 3592bfce19e8c5ddfdb5c3cf07e5fad83c812879 Mon Sep 17 00:00:00 2001
From: Patrick <patway99@gmail.com>
Date: Fri, 27 May 2022 13:26:14 -0700
Subject: [PATCH] Update UseDiamondOperator to ignore NewClass initializers for
 variables having a null or unknown type.  (issue #1297)

---
 .../java/cleanup/UseDiamondOperator.java       | 13 +++++++++----
 .../java/cleanup/UseDiamondOperatorTest.kt     | 18 ++++++++++++++++++
 2 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/rewrite-java/src/main/java/org/openrewrite/java/cleanup/UseDiamondOperator.java b/rewrite-java/src/main/java/org/openrewrite/java/cleanup/UseDiamondOperator.java
index c776894517b5..537b47b2a4cb 100644
--- a/rewrite-java/src/main/java/org/openrewrite/java/cleanup/UseDiamondOperator.java
+++ b/rewrite-java/src/main/java/org/openrewrite/java/cleanup/UseDiamondOperator.java
@@ -20,10 +20,7 @@
 import org.openrewrite.Recipe;
 import org.openrewrite.TreeVisitor;
 import org.openrewrite.java.JavaIsoVisitor;
-import org.openrewrite.java.tree.J;
-import org.openrewrite.java.tree.JavaVarKeyword;
-import org.openrewrite.java.tree.Space;
-import org.openrewrite.java.tree.TypeUtils;
+import org.openrewrite.java.tree.*;
 import org.openrewrite.marker.Markers;
 
 import java.time.Duration;
@@ -60,6 +57,14 @@ protected TreeVisitor<?, ExecutionContext> getVisitor() {
 
         return new JavaIsoVisitor<ExecutionContext>() {
 
+            @Override
+            public J.VariableDeclarations visitVariableDeclarations(J.VariableDeclarations multiVariable, ExecutionContext executionContext) {
+                if (multiVariable.getType() == null || multiVariable.getType() instanceof JavaType.Unknown) {
+                    return multiVariable;
+                }
+                return super.visitVariableDeclarations(multiVariable, executionContext);
+            }
+
             @Override
             public J.NewClass visitNewClass(J.NewClass newClass, ExecutionContext executionContext) {
                 J.NewClass n = super.visitNewClass(newClass, executionContext);
diff --git a/rewrite-test/src/main/kotlin/org/openrewrite/java/cleanup/UseDiamondOperatorTest.kt b/rewrite-test/src/main/kotlin/org/openrewrite/java/cleanup/UseDiamondOperatorTest.kt
index cca02a868960..05fbe1de73c5 100644
--- a/rewrite-test/src/main/kotlin/org/openrewrite/java/cleanup/UseDiamondOperatorTest.kt
+++ b/rewrite-test/src/main/kotlin/org/openrewrite/java/cleanup/UseDiamondOperatorTest.kt
@@ -16,6 +16,7 @@
 package org.openrewrite.java.cleanup
 
 import org.junit.jupiter.api.Test
+import org.openrewrite.Issue
 import org.openrewrite.Recipe
 import org.openrewrite.java.JavaParser
 import org.openrewrite.java.JavaRecipeTest
@@ -54,6 +55,23 @@ interface UseDiamondOperatorTest: JavaRecipeTest {
         """
     )
 
+    @Issue("https://github.com/openrewrite/rewrite/issues/1297")
+    @Test
+    fun `do not use diamond operators for variables having null or unknown types`(jp: JavaParser) = assertUnchanged(
+        jp,
+        before = """
+            import lombok.val;
+            import java.util.ArrayList;
+
+            class Test<X, Y> {
+                void test() {
+                    val ls = new ArrayList<String>();
+                    UnknownThing o = new UnknownThing<String>();
+                }
+            }
+        """
+    )
+
     @Test
     fun noLeftSide(jp: JavaParser) = assertUnchanged(
         parser = jp,