F2 rename of Lombok @Singular attribute does nothing

Signed-off-by: Snjezana Peco <snjezana.peco@redhat.com>

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/JDTUtils.java

@@ -109,6 +109,7 @@
 import org.eclipse.jdt.internal.codeassist.impl.Engine;
 import org.eclipse.jdt.internal.compiler.lookup.Binding;
 import org.eclipse.jdt.internal.compiler.lookup.MethodBinding;
+import org.eclipse.jdt.internal.core.NamedMember;
 import org.eclipse.jdt.internal.core.manipulation.JavaElementLabelComposerCore;
 import org.eclipse.jdt.internal.core.manipulation.JavaElementLabelsCore;
 import org.eclipse.jdt.internal.core.manipulation.search.IOccurrencesFinder.OccurrenceLocation;
@@ -1003,7 +1004,18 @@ public static IJavaElement[] findElementsAtSelection(ITypeRoot unit, int line, i
 			return null;
 		}
 		if (offset > -1) {
-			return unit.codeSelect(offset, 0);
+			IJavaElement[] elements = unit.codeSelect(offset, 0);
+			// a workaround for https://github.com/redhat-developer/vscode-java/issues/3203
+			if (elements == null || elements.length == 0) {
+				IJavaElement element = unit.getElementAt(offset);
+				if (element instanceof NamedMember namedMember) {
+					ISourceRange range = namedMember.getNameRange();
+					if (range.getOffset() <= offset && (range.getOffset() + range.getLength()) >= offset) {
+						return new IJavaElement[] { element };
+					}
+				}
+			}
+			return elements;
 		}
 		return null;
 	}

org.eclipse.jdt.ls.tests/projects/maven/mavenlombok/src/main/java/org/sample/Test2.java

@@ -0,0 +1,12 @@
+package org.sample;
+import java.util.List;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.Singular;
+@Builder
+@Getter
+public class Test2 {
+	@Singular("singular")
+	List<String> singulars;
+	List<String> normals;
+}

org.eclipse.jdt.ls.tests/src/org/eclipse/jdt/ls/core/internal/handlers/RenameHandlerTest.java

@@ -593,6 +593,25 @@ public void testRenameTypeLombok() throws Exception {
 		assertEquals(expected, TextEditUtil.apply(source, edit.getChanges().get(JDTUtils.toURI(cu))));
 	}
 
+	// this test should pass when starting with -javaagent:<lombok_jar> (-javagent:~/.m2/repository/org/projectlombok/lombok/1.18.28/lombok-1.18.28.jar)
+	// https://github.com/redhat-developer/vscode-java/issues/3203
+	@Test
+	public void testLombokSingular() throws Exception {
+		when(preferenceManager.getPreferences().isImportMavenEnabled()).thenReturn(true);
+		importProjects("maven/mavenlombok");
+		IProject project = ResourcesPlugin.getWorkspace().getRoot().getProject("mavenlombok");
+		IFile file = project.getFile("src/main/java/org/sample/Test2.java");
+		assertTrue(file.exists());
+		ICompilationUnit cu = JavaCore.createCompilationUnitFrom(file);
+		Position pos = new Position(9, 18);
+		String source = cu.getSource();
+		String expected = source.replace("singulars", "singulars2");
+		WorkspaceEdit edit = getRenameEdit(cu, pos, "singulars2");
+		assertNotNull(edit);
+		assertEquals(1, edit.getChanges().size());
+		assertEquals(expected, TextEditUtil.apply(source, edit.getChanges().get(JDTUtils.toURI(cu))));
+	}
+
 	// this test should pass when starting with -javaagent:<lombok_jar> (-javagent:~/.m2/repository/org/projectlombok/lombok/1.18.28/lombok-1.18.28.jar)
 	// https://github.com/redhat-developer/vscode-java/issues/2805
 	@Test