Fix Lombok recipes incorrectly replacing getters/setters accessing other objects' fields (#873)

* Fix UseLombokGetter incorrectly replacing getters that access fields of other objects

Fixes #872

The UseLombokGetter recipe was incorrectly removing getter methods when
the method body referenced a field of another object (e.g.,
`return sample.number;` where `sample` is a field of the current class).

The issue was in LombokUtils.isGetter() when handling J.FieldAccess
expressions. Previously, it checked if the target object was a field of
the current class, then incorrectly assumed the accessed field should
be annotated with @Getter.

The fix ensures that only `this.field` patterns are handled for
J.FieldAccess expressions, preventing the recipe from replacing getters
that access fields of other objects.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

* Apply same fix to UseLombokSetter for consistency

The setter logic had the same issue as the getter - it was incorrectly
replacing setter methods when they set fields of other objects
(e.g., `sample.number = value;`).

Applied the same fix: only handle `this.field` patterns for J.FieldAccess
expressions in the isSetter() method.

Added test case to verify the fix.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

---------

Co-authored-by: Claude <[email protected]>

Author: timtebeek

src/main/java/org/openrewrite/java/migrate/lombok/LombokUtils.java

@@ -73,15 +73,18 @@ static boolean isGetter(Cursor cursor, AnnotationService service) {
         } else if (returnExpression instanceof J.FieldAccess) {
             J.FieldAccess fieldAccess = (J.FieldAccess) returnExpression;
             Expression target = fieldAccess.getTarget();
-            if (target instanceof J.Identifier && ((J.Identifier) target).getFieldType() != null &&
-                    declaringType == ((J.Identifier) target).getFieldType().getOwner()) {
-                // Don't replace instance methods accessing static fields
+            // Only handle "this.field" pattern, not "someObject.field"
+            if (target instanceof J.Identifier && "this".equals(((J.Identifier) target).getSimpleName())) {
+                // Check field is declared on method type
                 if (fieldAccess.getName().getFieldType() != null &&
-                        fieldAccess.getName().getFieldType().hasFlags(Flag.Static)) {
-                    return false;
+                        declaringType == fieldAccess.getName().getFieldType().getOwner()) {
+                    // Don't replace instance methods accessing static fields
+                    if (fieldAccess.getName().getFieldType().hasFlags(Flag.Static)) {
+                        return false;
+                    }
+                    // Check return: type and matching field name
+                    return hasMatchingTypeAndGetterName(method, fieldAccess.getType(), fieldAccess.getSimpleName());
                 }
-                // Check return: type and matching field name
-                return hasMatchingTypeAndGetterName(method, fieldAccess.getType(), fieldAccess.getSimpleName());
             }
         }
         return false;
@@ -172,12 +175,14 @@ static boolean isSetter(Cursor cursor, AnnotationService service) {
             J.FieldAccess assignedField = (J.FieldAccess) variable;
             if (hasMatchingSetterMethodName(method, assignedField.getSimpleName())) {
                 Expression target = assignedField.getTarget();
-                // Check field is declared on method type
-                if (target instanceof J.Identifier && ((J.Identifier) target).getFieldType() != null &&
-                        declaringType == ((J.Identifier) target).getFieldType().getOwner()) {
-                    // Don't replace instance methods accessing static fields
-                    return assignedField.getName().getFieldType() != null &&
-                            !assignedField.getName().getFieldType().hasFlags(Flag.Static);
+                // Only handle "this.field" pattern, not "someObject.field"
+                if (target instanceof J.Identifier && "this".equals(((J.Identifier) target).getSimpleName())) {
+                    // Check field is declared on method type
+                    if (assignedField.getName().getFieldType() != null &&
+                            declaringType == assignedField.getName().getFieldType().getOwner()) {
+                        // Don't replace instance methods accessing static fields
+                        return !assignedField.getName().getFieldType().hasFlags(Flag.Static);
+                    }
                 }
             }
         }

src/test/java/org/openrewrite/java/migrate/lombok/UseLombokGetterTest.java

@@ -613,4 +613,29 @@ int getField() {
           )
         );
     }
+
+    @Issue("https://github.com/openrewrite/rewrite-migrate-java/issues/872")
+    @Test
+    void noChangeWhenMethodReturnsFieldOfAnotherObject() {
+        rewriteRun(// language=java
+          java(
+            """
+              public class A {
+
+                  private class Sample {
+                      public Long number;
+                  }
+
+                  private class Inner {
+                      static Sample sample = null;
+
+                      private Long getNumber() {
+                          return sample.number;
+                      }
+                  }
+              }
+              """
+          )
+        );
+    }
 }

src/test/java/org/openrewrite/java/migrate/lombok/UseLombokSetterTest.java

@@ -622,4 +622,29 @@ void setField(int field) {
           )
         );
     }
+
+    @Issue("https://github.com/openrewrite/rewrite-migrate-java/issues/872")
+    @Test
+    void noChangeWhenMethodSetsFieldOfAnotherObject() {
+        rewriteRun(// language=java
+          java(
+            """
+              public class A {
+
+                  private class Sample {
+                      public Long number;
+                  }
+
+                  private class Inner {
+                      static Sample sample = null;
+
+                      private void setNumber(Long value) {
+                          sample.number = value;
+                      }
+                  }
+              }
+              """
+          )
+        );
+    }
 }