fix: retain comments without specialized placements

src/main/java/spoon/support/compiler/jdt/JDTCommentBuilder.java

@@ -533,10 +533,12 @@ public <A extends Annotation> void visitCtAnnotation(CtAnnotation<A> e) {
 		// now we make sure that there is a parent
 		// if there is no parent
 		if (!comment.isParentInitialized()) {
-			// that's a serious error, there is something to debug
-			LOGGER.error("\"" + comment + "\" cannot be added into the AST, with parent " + commentParent.getClass()
-					+ " at " + commentParent.getPosition().toString()
+			// A specialized visitor may not find a suitable child, for example when a
+			// comment is placed next to an operator or inside an empty module directive.
+			LOGGER.error("\"" + comment + "\" cannot be added to a specialized AST child; attaching it to parent "
+					+ commentParent.getClass() + " at " + commentParent.getPosition().toString()
 					+ ", please report the bug by posting on https://github.com/INRIA/spoon/issues/2482");
+			commentParent.addComment(comment);
 		}
 	}
 

src/test/java/spoon/test/comment/CommentTest.java

@@ -73,6 +73,7 @@
 import spoon.support.DefaultCoreFactory;
 import spoon.support.JavaOutputProcessor;
 import spoon.support.StandardEnvironment;
+import spoon.support.compiler.VirtualFile;
 import spoon.support.compiler.jdt.JDTSnippetCompiler;
 import spoon.support.reflect.code.CtCommentImpl;
 import spoon.test.comment.testclasses.BlockComment;
@@ -106,6 +107,7 @@
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
+import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
@@ -1277,34 +1279,71 @@ public void testAnnotationComments(CtModel model) {
 	}
 
 	@ModelTest("./src/test/java/spoon/test/comment/testclasses/ArrayAccessComments.java")
-	@GitHubIssue(issueNumber = 2482, fixed = false)
+	@GitHubIssue(issueNumber = 2482, fixed = true)
 	public void testArrayAccessComments(CtModel model) {
 		//contract: comments at array accesses should be properly added to the AST
 		List<CtComment> comments = model.getElements(new TypeFilter<>(CtComment.class));
 		List<CtArrayAccess<?, ?>> arrayAccesses = model.getElements(new TypeFilter<>(CtArrayAccess.class));
 
-		assertEquals(2,comments.size());
-		assertEquals("comment 1", comments.get(0).getContent());
-		assertEquals("comment 2", comments.get(1).getContent());
-
-		assertEquals(1, arrayAccesses.get(0).getComments().size());
-		assertEquals("comment 1", arrayAccesses.get(0).getComments().get(0).getContent());
-		assertEquals(1, arrayAccesses.get(1).getComments().size());
-		assertEquals("comment 2", arrayAccesses.get(1).getComments().get(0).getContent());
+		assertThat(comments)
+			.extracting(CtComment::getContent)
+			.containsExactly("comment 1", "comment 2");
+		assertThat(arrayAccesses)
+			.satisfiesExactly(
+				first -> assertThat(first.getComments())
+					.extracting(CtComment::getContent)
+					.containsExactly("comment 1"),
+				second -> assertThat(second.getComments())
+					.extracting(CtComment::getContent)
+					.containsExactly("comment 2"));
 	}
 
 	@ModelTest("./src/test/java/spoon/test/comment/testclasses/BinaryOperatorComments.java")
-	@GitHubIssue(issueNumber = 2482, fixed = false)
+	@GitHubIssue(issueNumber = 2482, fixed = true)
 	public void testBinaryOperatorComments(CtModel model) {
 		//contract: comments at binary operators should be properly added to the AST
 		List<CtComment> comments = model.getElements(new TypeFilter<>(CtComment.class));
 		List<CtBinaryOperator<?>> binaryOperators = model.getElements(new TypeFilter<>(CtBinaryOperator.class));
 
-		assertEquals(1, comments.size());
-		assertEquals("comment 1", comments.get(0).getContent());
+		assertThat(comments)
+			.extracting(CtComment::getContent)
+			.containsExactly("comment 1");
+		assertThat(binaryOperators)
+			.singleElement()
+			.satisfies(binaryOperator -> assertThat(binaryOperator.getComments())
+				.extracting(CtComment::getContent)
+				.containsExactly("comment 1"));
+	}
 
-		assertEquals(1, binaryOperators.get(0).getComments().size());
-		assertEquals("comment 1", binaryOperators.get(0).getComments().get(0).getContent());
+	@ModelTest(code = "@Deprecated(/* marker */) class CommentInEmptyAnnotation {}")
+	public void testCommentInEmptyAnnotationFallsBackToAnnotation(CtModel model) {
+		// contract: a comment is retained on its enclosing annotation when the annotation has no value expression
+		assertThat(model.getElements(new TypeFilter<CtAnnotation<?>>(CtAnnotation.class)))
+			.singleElement()
+			.satisfies(annotation -> assertThat(annotation.getComments())
+				.extracting(CtComment::getContent)
+				.containsExactly("marker"));
+	}
+
+	@Test
+	public void testCommentInModuleWithoutDirectivesFallsBackToModule() {
+		// contract: a comment is retained on its enclosing module when there is no directive to receive it
+		Launcher launcher = new Launcher();
+		launcher.getEnvironment().setComplianceLevel(9);
+		launcher.getEnvironment().setNoClasspath(true);
+		launcher.addInputResource(new VirtualFile("""
+			module comment.fallback {
+				// exports disabled
+			}
+			""", "module-info.java"));
+
+		CtModel model = launcher.buildModel();
+		assertThat(model.getAllModules())
+			.filteredOn(candidate -> candidate.getSimpleName().equals("comment.fallback"))
+			.singleElement()
+			.satisfies(module -> assertThat(module.getComments())
+				.extracting(CtComment::getContent)
+				.containsExactly("exports disabled"));
 	}
 
 	@ModelTest("./src/test/java/spoon/test/comment/testclasses/TypeParameterComments.java")