Problem parsing unknown Javadoc tag

rewrite-java-11/src/main/java/org/openrewrite/java/isolated/ReloadableJava11JavadocVisitor.java

@@ -32,6 +32,7 @@
 import org.openrewrite.Tree;
 import org.openrewrite.internal.ListUtils;
 import org.openrewrite.internal.lang.Nullable;
+import org.openrewrite.java.marker.LeadingBrace;
 import org.openrewrite.java.tree.*;
 import org.openrewrite.marker.Markers;
 
@@ -750,8 +751,16 @@ private JavaType.Variable fieldReferenceType(DCTree.DCReference ref, @Nullable J
 
     @Override
     public Tree visitReturn(ReturnTree node, List<Javadoc> body) {
-        body.addAll(sourceBefore("@return"));
-        return new Javadoc.Return(randomId(), Markers.EMPTY, convertMultiline(node.getDescription()));
+        List<Javadoc> before;
+        Markers markers = Markers.EMPTY;
+        if (source.startsWith("{", cursor)) {
+            markers = markers.addIfAbsent(new LeadingBrace(Tree.randomId()));
+            before = sourceBefore("{@return");
+        } else {
+            before = sourceBefore("@return");
+        }
+        body.addAll(before);
+        return new Javadoc.Return(randomId(), markers, convertMultiline(node.getDescription()));
     }
 
     @Override

rewrite-java-17/src/main/java/org/openrewrite/java/isolated/ReloadableJava17JavadocVisitor.java

@@ -35,6 +35,7 @@
 import org.openrewrite.Tree;
 import org.openrewrite.internal.ListUtils;
 import org.openrewrite.internal.lang.Nullable;
+import org.openrewrite.java.marker.LeadingBrace;
 import org.openrewrite.java.tree.*;
 import org.openrewrite.marker.Markers;
 
@@ -753,8 +754,16 @@ private JavaType.Variable fieldReferenceType(DCTree.DCReference ref, @Nullable J
 
     @Override
     public Tree visitReturn(ReturnTree node, List<Javadoc> body) {
-        body.addAll(sourceBefore("@return"));
-        return new Javadoc.Return(randomId(), Markers.EMPTY, convertMultiline(node.getDescription()));
+        List<Javadoc> before;
+        Markers markers = Markers.EMPTY;
+        if (source.startsWith("{", cursor)) {
+            markers = markers.addIfAbsent(new LeadingBrace(Tree.randomId()));
+            before = sourceBefore("{@return");
+        } else {
+            before = sourceBefore("@return");
+        }
+        body.addAll(before);
+        return new Javadoc.Return(randomId(), markers, convertMultiline(node.getDescription()));
     }
 
     @Override
@@ -978,6 +987,7 @@ private List<Javadoc> sourceBefore(String delim) {
         if (endIndex < 0) {
             throw new IllegalStateException("Expected to be able to find " + delim);
         }
+
         List<Javadoc> before = whitespaceBefore();
         cursor += delim.length();
         return before;

rewrite-java-21/src/main/java/org/openrewrite/java/isolated/ReloadableJava21JavadocVisitor.java

@@ -35,6 +35,7 @@
 import org.openrewrite.Tree;
 import org.openrewrite.internal.ListUtils;
 import org.openrewrite.internal.lang.Nullable;
+import org.openrewrite.java.marker.LeadingBrace;
 import org.openrewrite.java.tree.*;
 import org.openrewrite.marker.Markers;
 
@@ -753,8 +754,16 @@ private JavaType.Variable fieldReferenceType(DCTree.DCReference ref, @Nullable J
 
     @Override
     public Tree visitReturn(ReturnTree node, List<Javadoc> body) {
-        body.addAll(sourceBefore("@return"));
-        return new Javadoc.Return(randomId(), Markers.EMPTY, convertMultiline(node.getDescription()));
+        List<Javadoc> before;
+        Markers markers = Markers.EMPTY;
+        if (source.startsWith("{", cursor)) {
+            markers = markers.addIfAbsent(new LeadingBrace(Tree.randomId()));
+            before = sourceBefore("{@return");
+        } else {
+            before = sourceBefore("@return");
+        }
+        body.addAll(before);
+        return new Javadoc.Return(randomId(), markers, convertMultiline(node.getDescription()));
     }
 
     @Override

rewrite-java-8/src/main/java/org/openrewrite/java/ReloadableJava8JavadocVisitor.java

@@ -32,6 +32,7 @@
 import org.openrewrite.Tree;
 import org.openrewrite.internal.ListUtils;
 import org.openrewrite.internal.lang.Nullable;
+import org.openrewrite.java.marker.LeadingBrace;
 import org.openrewrite.java.tree.*;
 import org.openrewrite.marker.Markers;
 
@@ -704,8 +705,16 @@ private JavaType.Variable fieldReferenceType(DCTree.DCReference ref, @Nullable J
 
     @Override
     public Tree visitReturn(ReturnTree node, List<Javadoc> body) {
-        body.addAll(sourceBefore("@return"));
-        return new Javadoc.Return(randomId(), Markers.EMPTY, convertMultiline(node.getDescription()));
+        List<Javadoc> before;
+        Markers markers = Markers.EMPTY;
+        if (source.startsWith("{", cursor)) {
+            markers = markers.addIfAbsent(new LeadingBrace(Tree.randomId()));
+            before = sourceBefore("{@return");
+        } else {
+            before = sourceBefore("@return");
+        }
+        body.addAll(before);
+        return new Javadoc.Return(randomId(), markers, convertMultiline(node.getDescription()));
     }
 
     @Override

rewrite-java-tck/src/main/java/org/openrewrite/java/tree/JavadocTest.java

@@ -1748,4 +1748,36 @@ class Test {
           )
         );
     }
+
+    @Test
+    void returnOpeningAndClosingBrace() {
+        rewriteRun(
+          java(
+            """
+              interface Test {
+              	/**
+              	 * {@return 42}
+              	 */
+              	int foo();
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void returnOpeningBraceOnly() {
+        rewriteRun(
+          java(
+            """
+              interface Test {
+              	/**
+              	 * {@return 42
+              	 */
+              	int foo();
+              }
+              """
+          )
+        );
+    }
 }

rewrite-java/src/main/java/org/openrewrite/java/JavaIsoVisitor.java

@@ -23,7 +23,7 @@
  * This iso(morphic) refactoring visitor is the appropriate base class for most Java refactoring visitors.
  * It comes with an additional constraint compared to the non-isomorphic JavaRefactorVisitor:
  * Each visit method must return an AST element of the same type as the one being visited.
- *
+ * <p>
  * For visitors that do not need the extra flexibility of JavaRefactorVisitor, this constraint
  * makes for a more pleasant visitor authoring experience as less casting will be required.
  */

rewrite-java/src/main/java/org/openrewrite/java/JavadocPrinter.java

@@ -18,6 +18,7 @@
 import org.openrewrite.Cursor;
 import org.openrewrite.PrintOutputCapture;
 import org.openrewrite.internal.lang.Nullable;
+import org.openrewrite.java.marker.LeadingBrace;
 import org.openrewrite.java.tree.*;
 import org.openrewrite.marker.Marker;
 import org.openrewrite.marker.Markers;
@@ -206,6 +207,9 @@ public Javadoc visitProvides(Javadoc.Provides provides, PrintOutputCapture<P> p)
     @Override
     public Javadoc visitReturn(Javadoc.Return aReturn, PrintOutputCapture<P> p) {
         beforeSyntax(aReturn, p);
+        if (aReturn.getMarkers().findFirst(LeadingBrace.class).isPresent()) {
+            p.append("{");
+        }
         p.append("@return");
         visit(aReturn.getDescription(), p);
         afterSyntax(aReturn, p);

rewrite-java/src/main/java/org/openrewrite/java/marker/LeadingBrace.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2023 the original author or authors.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.java.marker;
+
+import lombok.Value;
+import lombok.With;
+import org.openrewrite.marker.Marker;
+
+import java.util.UUID;
+
+/**
+ * JavaDoc tags like @return that may be written with a leading brace.
+ */
+@Value
+@With
+public class LeadingBrace implements Marker {
+    UUID id;
+}