Rename ProtoFieldNullComparison to something less intrinsically proto…

…-ish, in preparation for generalizing it a bit.

PiperOrigin-RevId: 487541689

core/src/main/java/com/google/errorprone/bugpatterns/ProtoFieldNullComparison.java → core/src/main/java/com/google/errorprone/bugpatterns/ImpossibleNullComparison.java

@@ -70,8 +70,12 @@
 import javax.annotation.Nullable;
 
 /** Matches comparison of proto fields to {@code null}. */
-@BugPattern(summary = "Protobuf fields cannot be null.", severity = ERROR)
-public class ProtoFieldNullComparison extends BugChecker implements CompilationUnitTreeMatcher {
+@BugPattern(
+    summary = "Protobuf fields cannot be null.",
+    altNames = "ProtoFieldNullComparison",
+    severity = ERROR)
+public final class ImpossibleNullComparison extends BugChecker
+    implements CompilationUnitTreeMatcher {
 
   // TODO(b/111109484): Try to consolidate these with NullnessPropagationTransfer.
   private static final Matcher<ExpressionTree> CHECK_NOT_NULL =
@@ -138,23 +142,23 @@ private static boolean isNull(ExpressionTree tree) {
 
   private final boolean matchTestAssertions;
 
-  public ProtoFieldNullComparison(ErrorProneFlags flags) {
+  public ImpossibleNullComparison(ErrorProneFlags flags) {
     this.matchTestAssertions =
         flags.getBoolean("ProtoFieldNullComparison:MatchTestAssertions").orElse(true);
   }
 
   @Override
   public Description matchCompilationUnit(CompilationUnitTree tree, VisitorState state) {
-    ProtoNullComparisonScanner scanner = new ProtoNullComparisonScanner(state);
+    NullComparisonScanner scanner = new NullComparisonScanner(state);
     scanner.scan(state.getPath(), null);
     return Description.NO_MATCH;
   }
 
-  private class ProtoNullComparisonScanner extends TreePathScanner<Void, Void> {
+  private class NullComparisonScanner extends TreePathScanner<Void, Void> {
     private final Map<Symbol, ExpressionTree> effectivelyFinalValues = new HashMap<>();
     private final VisitorState state;
 
-    private ProtoNullComparisonScanner(VisitorState state) {
+    private NullComparisonScanner(VisitorState state) {
       this.state = state;
     }
 

core/src/main/java/com/google/errorprone/scanner/BuiltInCheckerSuppliers.java

@@ -156,6 +156,7 @@
 import com.google.errorprone.bugpatterns.ImmutableMemberCollection;
 import com.google.errorprone.bugpatterns.ImmutableSetForContains;
 import com.google.errorprone.bugpatterns.ImplementAssertionWithChaining;
+import com.google.errorprone.bugpatterns.ImpossibleNullComparison;
 import com.google.errorprone.bugpatterns.Incomparable;
 import com.google.errorprone.bugpatterns.IncompatibleModifiersChecker;
 import com.google.errorprone.bugpatterns.InconsistentCapitalization;
@@ -285,7 +286,6 @@
 import com.google.errorprone.bugpatterns.PrivateSecurityContractProtoAccess;
 import com.google.errorprone.bugpatterns.ProtectedMembersInFinalClass;
 import com.google.errorprone.bugpatterns.ProtoBuilderReturnValueIgnored;
-import com.google.errorprone.bugpatterns.ProtoFieldNullComparison;
 import com.google.errorprone.bugpatterns.ProtoRedundantSet;
 import com.google.errorprone.bugpatterns.ProtoStringFieldReferenceEquality;
 import com.google.errorprone.bugpatterns.ProtoTruthMixedDescriptors;
@@ -669,6 +669,7 @@ public static ScannerSupplier errorChecks() {
           IdentityHashMapBoxing.class,
           IgnoredPureGetter.class,
           ImmutableChecker.class,
+          ImpossibleNullComparison.class,
           Incomparable.class,
           IncompatibleArgumentType.class,
           IncompatibleModifiersChecker.class,
@@ -736,7 +737,6 @@ public static ScannerSupplier errorChecks() {
           PreconditionsInvalidPlaceholder.class,
           PrivateSecurityContractProtoAccess.class,
           ProtoBuilderReturnValueIgnored.class,
-          ProtoFieldNullComparison.class,
           ProtoStringFieldReferenceEquality.class,
           ProtoTruthMixedDescriptors.class,
           ProtocolBufferOrdinal.class,

core/src/test/java/com/google/errorprone/bugpatterns/ProtoFieldNullComparisonTest.java → core/src/test/java/com/google/errorprone/bugpatterns/ImpossibleNullComparisonTest.java

@@ -26,10 +26,10 @@
  */
 @RunWith(JUnit4.class)
 @Ignore("b/130670448")
-public final class ProtoFieldNullComparisonTest {
+public final class ImpossibleNullComparisonTest {
 
   private final CompilationTestHelper compilationHelper =
-      CompilationTestHelper.newInstance(ProtoFieldNullComparison.class, getClass());
+      CompilationTestHelper.newInstance(ImpossibleNullComparison.class, getClass());
 
   @Test
   public void scalarCases() {
@@ -144,7 +144,7 @@ public void testMessageOrBuilderGetField() {
             "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
             "public class Test {",
             "  public boolean doIt(TestProtoMessage mob, FieldDescriptor f) {",
-            "    // BUG: Diagnostic contains: ProtoFieldNullComparison",
+            "    // BUG: Diagnostic contains:",
             "    return mob.getField(f) == null;",
             "  }",
             "}")
@@ -161,7 +161,7 @@ public void testMessageOrBuilderGetFieldCast() {
             "public class Test {",
             "  public boolean doIt(TestProtoMessage mob, FieldDescriptor f) {",
             "    String s = ((String) mob.getField(f));",
-            "    // BUG: Diagnostic contains: ProtoFieldNullComparison",
+            "    // BUG: Diagnostic contains:",
             "    return s == null;",
             "  }",
             "}")
@@ -177,7 +177,7 @@ public void testExtendableMessageGetExtension1param() {
             "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
             "public class Test {",
             "  public void test(TestProtoMessage e, ExtensionLite extensionLite) {",
-            "    // BUG: Diagnostic contains: ProtoFieldNullComparison",
+            "    // BUG: Diagnostic contains:",
             "    boolean a = e.getExtension(extensionLite) == null;",
             "  }",
             "}")
@@ -193,7 +193,7 @@ public void testMessageOrBuilderGetRepeatedField() {
             "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
             "public class Test {",
             "  public void doIt(TestProtoMessage mob, FieldDescriptor f) {",
-            "    // BUG: Diagnostic contains: ProtoFieldNullComparison",
+            "    // BUG: Diagnostic contains:",
             "    boolean a = mob.getRepeatedField(f, 0) == null;",
             "  }",
             "}")
@@ -209,7 +209,7 @@ public void testExtendableMessageGetExtension2param() {
             "import com.google.errorprone.bugpatterns.proto.ProtoTest.TestProtoMessage;",
             "public class Test {",
             "  public void test(TestProtoMessage e, ExtensionLite extensionLite) {",
-            "    // BUG: Diagnostic contains: ProtoFieldNullComparison",
+            "    // BUG: Diagnostic contains:",
             "    boolean a = e.getExtension(extensionLite, 0) == null;",
             "  }",
             "}")
@@ -228,7 +228,7 @@ public void repeated() {
             "public class Test {",
             " public void test(ExtensionLite<TestProtoMessage,",
             "  List<TestFieldProtoMessage>> e, TestProtoMessage message) {",
-            "    // BUG: Diagnostic contains: ProtoFieldNullComparison",
+            "    // BUG: Diagnostic contains:",
             "    boolean y = message.getExtension(e) == null;",
             " }",
             "}")
@@ -255,7 +255,7 @@ public void repeated2() {
             " ImmutableList.Builder extensionList = ImmutableList.builder();",
             " int extensionCount = mob.getExtensionCount(extension);",
             " for (int extensionIndex = 0; extensionIndex < extensionCount; ++extensionIndex) {",
-            "  // BUG: Diagnostic contains: ProtoFieldNullComparison",
+            "  // BUG: Diagnostic contains:",
             "  boolean y = mob.getExtension(extension) == null;",
             "  extensionList.add(mob.getExtension(extension));",
             " }",