fix missing ObjectEquals (#464)

* JAVA_LANG_OBJECT

* Apply formatter

---------

Co-authored-by: Vincent Potucek <[email protected]>
Co-authored-by: Tim te Beek <[email protected]>

Author: 3 people

src/main/java/org/openrewrite/staticanalysis/EqualsAvoidsNull.java

@@ -38,8 +38,10 @@
 public class EqualsAvoidsNull extends Recipe {
 
     private static final String JAVA_LANG_STRING = "java.lang.String";
+    private static final String JAVA_LANG_OBJECT = "java.lang.Object";
 
-    private static final MethodMatcher EQUALS = new MethodMatcher(JAVA_LANG_STRING + " equals(java.lang.Object)");
+    private static final MethodMatcher EQUALS_STRING = new MethodMatcher(JAVA_LANG_STRING + " equals(" + JAVA_LANG_OBJECT + ")");
+    private static final MethodMatcher EQUALS_OBJECT = new MethodMatcher(JAVA_LANG_OBJECT + " equals(" + JAVA_LANG_OBJECT + ")");
     private static final MethodMatcher EQUALS_IGNORE_CASE = new MethodMatcher(JAVA_LANG_STRING + " equalsIgnoreCase(" + JAVA_LANG_STRING + ")");
     private static final MethodMatcher CONTENT_EQUALS = new MethodMatcher(JAVA_LANG_STRING + " contentEquals(java.lang.CharSequence)");
 
@@ -66,7 +68,11 @@ public Duration getEstimatedEffortPerOccurrence() {
     @Override
     public TreeVisitor<?, ExecutionContext> getVisitor() {
         return Preconditions.check(
-                Preconditions.or(new UsesMethod<>(EQUALS), new UsesMethod<>(EQUALS_IGNORE_CASE), new UsesMethod<>(CONTENT_EQUALS)),
+                Preconditions.or(
+                        new UsesMethod<>(EQUALS_STRING),
+                        new UsesMethod<>(EQUALS_OBJECT),
+                        new UsesMethod<>(EQUALS_IGNORE_CASE),
+                        new UsesMethod<>(CONTENT_EQUALS)),
                 new JavaVisitor<ExecutionContext>() {
                     @Override
                     public J visitMethodInvocation(J.MethodInvocation method, ExecutionContext ctx) {
@@ -104,7 +110,8 @@ private boolean hasCompatibleArgument(J.MethodInvocation m) {
                     }
 
                     private boolean isStringComparisonMethod(J.MethodInvocation methodInvocation) {
-                        return EQUALS.matches(methodInvocation) ||
+                        return EQUALS_STRING.matches(methodInvocation) ||
+                                EQUALS_OBJECT.matches(methodInvocation) ||
                                 EQUALS_IGNORE_CASE.matches(methodInvocation) ||
                                 CONTENT_EQUALS.matches(methodInvocation);
                     }
@@ -116,8 +123,8 @@ private void maybeHandleParentBinary(J.MethodInvocation m, final Tree parent) {
                                 J.Binary potentialNullCheck = (J.Binary) ((J.Binary) parent).getLeft();
                                 if (isNullLiteral(potentialNullCheck.getLeft()) &&
                                         matchesSelect(potentialNullCheck.getRight(), requireNonNull(m.getSelect())) ||
-                                        isNullLiteral(potentialNullCheck.getRight()) &&
-                                        matchesSelect(potentialNullCheck.getLeft(), requireNonNull(m.getSelect()))) {
+                                    isNullLiteral(potentialNullCheck.getRight()) &&
+                                            matchesSelect(potentialNullCheck.getLeft(), requireNonNull(m.getSelect()))) {
                                     doAfterVisit(new JavaVisitor<ExecutionContext>() {
 
                                         private final J.Binary scope = (J.Binary) parent;

src/test/java/org/openrewrite/staticanalysis/EqualsAvoidsNullTest.java

@@ -113,6 +113,31 @@ void foo(String s) {
         );
     }
 
+    @Test
+    void ObjectEquals() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              class A {
+                  void foo(Object s) {
+                      if (s.equals("null")) {
+                      }
+                  }
+              }
+              """,
+            """
+              class A {
+                  void foo(Object s) {
+                      if ("null".equals(s)) {
+                      }
+                  }
+              }
+              """
+          )
+        );
+    }
+
     @Nested
     class ReplaceConstantMethodArg {