Remove fully qualified JavaDoc references from TypesInUse for RemoveUnusedImports (#5738)

* RemoveUnusedImports

* RemoveUnusedImports

* RemoveUnusedImports

* RemoveUnusedImports

* RemoveUnusedImports

* Reduce test

* Remove fully qualified JavaDoc references from TypesInUse

* Apply formatter to text blocks

* Also break `isFullyQualifiedJavaDocReference` on J.Block

---------

Co-authored-by: Vincent Potucek <vpotucek@me.com>
Co-authored-by: Tim te Beek <tim@moderne.io>

Author: 3 people

rewrite-java-test/src/test/java/org/openrewrite/java/RemoveUnusedImportsTest.java

@@ -132,6 +132,54 @@ public abstract class MyMapEntry<K, V> implements Entry<K, V> {
         );
     }
 
+    @Test
+    void retainImportIfUsedInJavaDoc() {
+        rewriteRun(
+          java(
+            """
+              import java.util.Date;
+              import java.util.List;
+
+              /**
+               * referencing {@link Date} only in doc
+               */
+              class Test {
+                  List list;
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void removeImportIfFullyQualifiedInJavaDoc() {
+        rewriteRun(
+          java(
+            """
+              import java.util.Date;
+              import java.util.List;
+
+              /**
+               * referencing {@link java.util.Date} only in doc
+               */
+              class Test2 {
+                  List list;
+              }
+              """,
+            """
+              import java.util.List;
+
+              /**
+               * referencing {@link java.util.Date} only in doc
+               */
+              class Test2 {
+                  List list;
+              }
+              """
+          )
+        );
+    }
+
     @Issue("https://github.com/openrewrite/rewrite/issues/1052")
     @Test
     void usedInJavadocWithThrows() {

rewrite-java/src/main/java/org/openrewrite/java/internal/TypesInUse.java

@@ -24,8 +24,10 @@
 import org.openrewrite.java.tree.J;
 import org.openrewrite.java.tree.JavaSourceFile;
 import org.openrewrite.java.tree.JavaType;
+import org.openrewrite.java.tree.Javadoc;
 
 import java.util.IdentityHashMap;
+import java.util.Iterator;
 import java.util.Objects;
 import java.util.Set;
 
@@ -100,12 +102,31 @@ public J.Lambda.Parameters visitLambdaParameters(J.Lambda.Parameters parameters,
                     } else {
                         usedMethods.add((JavaType.Method) javaType);
                     }
-                } else if (!(cursor.getValue() instanceof J.ClassDeclaration) && !(cursor.getValue() instanceof J.Lambda)) {
-                    // ignore type representing class declaration itself and inferred lambda types
+                } else if (!(cursor.getValue() instanceof J.ClassDeclaration) &&
+                        !(cursor.getValue() instanceof J.Lambda) &&
+                        !isFullyQualifiedJavaDocReference(cursor)) {
                     types.add(javaType);
                 }
             }
             return javaType;
         }
+
+        private boolean isFullyQualifiedJavaDocReference(Cursor cursor) {
+            // Fully qualified Javadoc references are _using_ those types as much as they are just references;
+            // TypesInUse entries determines what imports are retained, and for fully qualified these can be dropped
+            if (cursor.getValue() instanceof J.FieldAccess) {
+                Iterator<Object> path = cursor.getPath();
+                while (path.hasNext()) {
+                    Object o = path.next();
+                    if (o instanceof Javadoc.Reference) {
+                        return true;
+                    }
+                    if (o instanceof J.Block) {
+                        return false;
+                    }
+                }
+            }
+            return false;
+        }
     }
 }