From 23547ac2ef8ca0f3274fc7cbd82d656c62028486 Mon Sep 17 00:00:00 2001
From: Liam Miller-Cushon <cushon@google.com>
Date: Thu, 4 Apr 2024 17:38:26 -0700
Subject: [PATCH] Allow `CONST_CASE != null` in YodaCondition

Follow-up to https://github.com/google/error-prone/commit/9b2c2a9fc8dcea7c40ec6574c6325dc82f534abd

PiperOrigin-RevId: 622020333
---
 .../errorprone/bugpatterns/YodaCondition.java  |  3 +++
 .../bugpatterns/YodaConditionTest.java         | 18 ++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/YodaCondition.java b/core/src/main/java/com/google/errorprone/bugpatterns/YodaCondition.java
index 7a2055d6932..e37a4f74364 100644
--- a/core/src/main/java/com/google/errorprone/bugpatterns/YodaCondition.java
+++ b/core/src/main/java/com/google/errorprone/bugpatterns/YodaCondition.java
@@ -120,6 +120,9 @@ private static boolean seemsConstant(Tree tree) {
     if (constValue(tree) != null) {
       return true;
     }
+    if (tree.getKind().equals(Tree.Kind.NULL_LITERAL)) {
+      return true;
+    }
     var symbol = getSymbol(tree);
     if (!(symbol instanceof VarSymbol)) {
       return false;
diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/YodaConditionTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/YodaConditionTest.java
index eaf08537c49..6185c7d6660 100644
--- a/core/src/test/java/com/google/errorprone/bugpatterns/YodaConditionTest.java
+++ b/core/src/test/java/com/google/errorprone/bugpatterns/YodaConditionTest.java
@@ -18,6 +18,7 @@
 
 import com.google.errorprone.BugCheckerRefactoringTestHelper;
 import com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers;
+import com.google.errorprone.CompilationTestHelper;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
@@ -27,6 +28,9 @@ public final class YodaConditionTest {
   private final BugCheckerRefactoringTestHelper refactoring =
       BugCheckerRefactoringTestHelper.newInstance(YodaCondition.class, getClass());
 
+  private final CompilationTestHelper testHelper =
+      CompilationTestHelper.newInstance(YodaCondition.class, getClass());
+
   @Test
   public void primitive() {
     refactoring
@@ -205,4 +209,18 @@ public void provablyNonNull_nullIntolerantFix() {
             "}")
         .doTest();
   }
+
+  @Test
+  public void nullableConstant() {
+    testHelper
+        .addSourceLines(
+            "Test.java",
+            "class Test {",
+            "  private static final String CONST = null;",
+            "  public static boolean f() {",
+            "    return CONST != null;",
+            "  }",
+            "}")
+        .doTest();
+  }
 }