Handle null != CONST_CASE in YodaCondition

PiperOrigin-RevId: 636287602
google · May 22, 2024 · 13be411 · 13be411
1 parent ae77a5f
commit 13be411
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Showing 2 changed files with 57 additions and 8 deletions.
diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/YodaCondition.java b/core/src/main/java/com/google/errorprone/bugpatterns/YodaCondition.java
@@ -95,7 +95,7 @@ private Description fix(
  ExpressionTree rhs,
  boolean provideNullSafeFix,
  VisitorState state) {
- if (seemsConstant(lhs) && !seemsConstant(rhs)) {
+ if (yodaCondition(lhs, rhs)) {
  var description = buildDescription(lhs);
  if (provideNullSafeFix
  && !getNullnessValue(rhs, state, NullnessAnalysis.instance(state.context))
@@ -116,19 +116,40 @@ private Description fix(
  return NO_MATCH;
  }
 
- private static boolean seemsConstant(Tree tree) {
+ private static boolean yodaCondition(ExpressionTree lhs, ExpressionTree rhs) {
+ ConstantKind l = seemsConstant(lhs);
+ ConstantKind r = seemsConstant(rhs);
+ return l.constness > r.constness;
+ }
+
+ enum ConstantKind {
+ NULL(3),
+ CONSTANT(2),
+ CONSTANT_VARIABLE(1),
+ NON_CONSTANT(0);
+
+ final int constness;
+
+ ConstantKind(int constness) {
+ this.constness = constness;
+ }
+ }
+
+ private static ConstantKind seemsConstant(Tree tree) {
  if (constValue(tree) != null) {
- return true;
+ return ConstantKind.CONSTANT;
  }
  if (tree.getKind().equals(Tree.Kind.NULL_LITERAL)) {
- return true;
+ return ConstantKind.NULL;
  }
  var symbol = getSymbol(tree);
- if (!(symbol instanceof VarSymbol)) {
- return false;
+ if (symbol instanceof VarSymbol
+ && (symbol.isEnum()
+ || (isStatic(symbol)
+ && CONSTANT_CASE.matcher(symbol.getSimpleName().toString()).matches()))) {
+ return ConstantKind.CONSTANT_VARIABLE;
  }
- return symbol.isEnum()
- || (isStatic(symbol) && CONSTANT_CASE.matcher(symbol.getSimpleName().toString()).matches());
+ return ConstantKind.NON_CONSTANT;
  }
 
  private static final Pattern CONSTANT_CASE = Pattern.compile("[A-Z0-9_]+");

diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/YodaConditionTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/YodaConditionTest.java
@@ -223,4 +223,32 @@ public void nullableConstant() {
  "}")
  .doTest();
  }
+
+ @Test
+ public void nullableYodaCondition() {
+ refactoring
+ .addInputLines(
+ "Test.java",
+ "class Test {",
+ " private static final String CONST = \"hello\";",
+ " public static boolean f(String foo) {",
+ " return null != foo;",
+ " }",
+ " public static boolean g() {",
+ " return null != CONST;",
+ " }",
+ "}")
+ .addOutputLines(
+ "Test.java",
+ "class Test {",
+ " private static final String CONST = \"hello\";",
+ " public static boolean f(String foo) {",
+ " return foo != null;",
+ " }",
+ " public static boolean g() {",
+ " return CONST != null;",
+ " }",
+ "}")
+ .doTest();
+ }
 }