Added handling of comment decorators (skip, note) in sequence diagram comments (#194)

README.md

@@ -42,7 +42,7 @@ Main features supported so far include:
     * Support for plain C99/C11 code (struct and units relationships) - [_example_](docs/test_cases/t00057.md)
     * C++20 concept constraints - [_example_](docs/test_cases/t00059.md)
 * **Sequence diagram generation**
-    * Generation of sequence diagram from specific method or function - [_example_](docs/test_cases/t00002.md)
+    * Generation of sequence diagram from specific method or function - [_example_](docs/test_cases/t20001.md)
     * Generation of loop and conditional statements - [_example_](docs/test_cases/t20021.md)
     * Generation of switch statements - [_example_](docs/test_cases/t20024.md)
     * Generation of try/catch blocks - [_example_](docs/test_cases/t20023.md)

src/common/clang_utils.cc

@@ -849,9 +849,8 @@ bool parse_source_location(const std::string &location_str, std::string &file,
     return true;
 }
 
-std::optional<std::string> get_expression_comment(
-    const clang::SourceManager &sm, const clang::ASTContext &context,
-    const clang::Stmt *stmt)
+clang::RawComment *get_expression_raw_comment(const clang::SourceManager &sm,
+    const clang::ASTContext &context, const clang::Stmt *stmt)
 {
     // First get the first line of the expression
     auto expr_begin = stmt->getSourceRange().getBegin();
@@ -859,17 +858,13 @@ std::optional<std::string> get_expression_comment(
 
     if (!context.Comments.empty())
         for (const auto [offset, raw_comment] :
-            *context.Comments.getCommentsInFile(sm.getMainFileID())) {
-
-            auto comment =
-                raw_comment->getFormattedText(sm, sm.getDiagnostics());
-
+            *context.Comments.getCommentsInFile(sm.getFileID(expr_begin))) {
             const auto comment_end_line = sm.getSpellingLineNumber(
                 raw_comment->getSourceRange().getEnd());
 
             if (expr_begin_line == comment_end_line ||
                 expr_begin_line == comment_end_line + 1)
-                return comment;
+                return raw_comment;
         }
 
     return {};

src/common/clang_utils.h

@@ -282,8 +282,15 @@ clang::QualType dereference(clang::QualType type);
 std::pair<clang::QualType, std::deque<common::model::context>>
 consume_type_context(clang::QualType type);
 
-std::optional<std::string> get_expression_comment(
-    const clang::SourceManager &sm, const clang::ASTContext &context,
-    const clang::Stmt *stmt);
+/**
+ * @brief Extract a comment before or next to a statement
+ *
+ * @param sm clang::SourceManager reference
+ * @param context clang::ASTContext reference
+ * @param stmt Pointer to the current clang::Stmt
+ * @return Pointer to a clang::RawComment* or nullptr
+ */
+clang::RawComment *get_expression_raw_comment(const clang::SourceManager &sm,
+    const clang::ASTContext &context, const clang::Stmt *stmt);
 
 } // namespace clanguml::common

src/common/visitor/translation_unit_visitor.cc

@@ -59,7 +59,6 @@ clang::SourceManager &translation_unit_visitor::source_manager() const
 void translation_unit_visitor::process_comment(
     const clang::NamedDecl &decl, clanguml::common::model::decorated_element &e)
 {
-
     assert(comment_visitor_.get() != nullptr);
 
     comment_visitor_->visit(decl, e);
@@ -67,12 +66,23 @@ void translation_unit_visitor::process_comment(
     const auto *comment =
         decl.getASTContext().getRawCommentForDeclNoCache(&decl);
 
+    process_comment(comment, decl.getASTContext().getDiagnostics(), e);
+}
+
+void translation_unit_visitor::process_comment(const clang::RawComment *comment,
+    clang::DiagnosticsEngine &de, clanguml::common::model::decorated_element &e)
+{
     if (comment != nullptr) {
+        auto [it, inserted] = processed_comments_.emplace(comment);
+
+        if (!inserted)
+            return;
+
         // Process clang-uml decorators in the comments
         // TODO: Refactor to use standard block comments processable by clang
         //       comments
-        e.add_decorators(decorators::parse(comment->getFormattedText(
-            source_manager_, decl.getASTContext().getDiagnostics())));
+        e.add_decorators(
+            decorators::parse(comment->getFormattedText(source_manager_, de)));
     }
 }
 

src/common/visitor/translation_unit_visitor.h

@@ -102,7 +102,7 @@ public:
 
 protected:
     /**
-     * @brief Set source location in diagram element
+     * @brief Process comment directives in comment attached to a declaration
      *
      * @param decl Reference to @ref clang::NamedDecl
      * @param element Reference to element to be updated
@@ -110,6 +110,17 @@ protected:
     void process_comment(const clang::NamedDecl &decl,
         clanguml::common::model::decorated_element &e);
 
+    /**
+     * @brief Process comment directives in raw comment
+     *
+     * @param comment clang::RawComment pointer
+     * @param de Reference to clang::DiagnosticsEngine
+     * @param element Reference to element to be updated
+     */
+    void process_comment(const clang::RawComment *comment,
+        clang::DiagnosticsEngine &de,
+        clanguml::common::model::decorated_element &e);
+
 private:
     clang::SourceManager &source_manager_;
 
@@ -118,5 +129,7 @@ private:
     std::filesystem::path relative_to_path_;
 
     std::filesystem::path translation_unit_path_;
+
+    std::set<const clang::RawComment *> processed_comments_;
 };
 } // namespace clanguml::common::visitor

src/sequence_diagram/generators/mermaid/sequence_diagram_generator.cc

@@ -56,12 +56,31 @@ void generator::generate_diagram_type(std::ostream &ostr) const
 void generator::generate_message_comment(
     std::ostream &ostr, const model::message &m) const
 {
-    if (!config().generate_message_comments() || !m.comment())
+    const auto &from = model().get_participant<model::participant>(m.from());
+    if (!from)
         return;
 
-    const auto &from = model().get_participant<model::participant>(m.from());
+    bool comment_generated_from_note_decorators{false};
+    for (const auto &decorator : m.decorators()) {
+        auto note = std::dynamic_pointer_cast<decorators::note>(decorator);
+        if (note && note->applies_to_diagram(config().name)) {
+            comment_generated_from_note_decorators = true;
 
-    if (!from)
+            ostr << indent(1) << "note over " << generate_alias(from.value())
+                 << ": ";
+
+            auto formatted_message = util::format_message_comment(
+                note->text, config().message_comment_width());
+
+            util::replace_all(formatted_message, "\n", "<br/>");
+            ostr << formatted_message << '\n';
+        }
+    }
+
+    if (comment_generated_from_note_decorators)
+        return;
+
+    if (!config().generate_message_comments() || !m.comment())
         return;
 
     ostr << indent(1) << "note over " << generate_alias(from.value()) << ": ";

src/sequence_diagram/generators/plantuml/sequence_diagram_generator.cc

@@ -279,12 +279,30 @@ void generator::generate_activity(const activity &a, std::ostream &ostr,
 void generator::generate_message_comment(
     std::ostream &ostr, const model::message &m) const
 {
-    if (!config().generate_message_comments() || !m.comment())
+    const auto &from = model().get_participant<model::participant>(m.from());
+    if (!from)
         return;
 
-    const auto &from = model().get_participant<model::participant>(m.from());
+    bool comment_generated_from_note_decorators{false};
+    for (const auto &decorator : m.decorators()) {
+        auto note = std::dynamic_pointer_cast<decorators::note>(decorator);
+        if (note && note->applies_to_diagram(config().name)) {
+            comment_generated_from_note_decorators = true;
 
-    if (!from)
+            ostr << "note over " << generate_alias(from.value()) << '\n';
+
+            ostr << util::format_message_comment(
+                        note->text, config().message_comment_width())
+                 << '\n';
+
+            ostr << "end note" << '\n';
+        }
+    }
+
+    if (comment_generated_from_note_decorators)
+        return;
+
+    if (!config().generate_message_comments() || !m.comment())
         return;
 
     ostr << "note over " << generate_alias(from.value()) << '\n';

src/sequence_diagram/model/diagram.cc

@@ -445,10 +445,11 @@ void diagram::print() const
                 const auto &to_participant = *participants_.at(message.to());
 
                 LOG_TRACE("       Message from={}, from_id={}, "
-                          "to={}, to_id={}, name={}, type={}",
+                          "to={}, to_id={}, name={}, type={}, comment={}",
                     from_participant.full_name(false), from_participant.id(),
                     to_participant.full_name(false), to_participant.id(),
-                    message.message_name(), to_string(message.type()));
+                    message.message_name(), to_string(message.type()),
+                    message.comment() ? message.comment().value() : "None");
             }
         }
     }

src/sequence_diagram/visitor/translation_unit_visitor.cc

@@ -613,8 +613,8 @@ bool translation_unit_visitor::TraverseIfStmt(clang::IfStmt *stmt)
             message m{message_t::kElseIf, current_caller_id};
             set_source_location(*stmt, m);
             m.condition_text(condition_text);
-            m.set_comment(clanguml::common::get_expression_comment(
-                source_manager(), *context().get_ast_context(), stmt));
+            m.set_comment(get_expression_comment(source_manager(),
+                *context().get_ast_context(), current_caller_id, stmt));
             diagram().add_block_message(std::move(m));
         }
         else {
@@ -623,8 +623,8 @@ bool translation_unit_visitor::TraverseIfStmt(clang::IfStmt *stmt)
             message m{message_t::kIf, current_caller_id};
             set_source_location(*stmt, m);
             m.condition_text(condition_text);
-            m.set_comment(clanguml::common::get_expression_comment(
-                source_manager(), *context().get_ast_context(), stmt));
+            m.set_comment(get_expression_comment(source_manager(),
+                *context().get_ast_context(), current_caller_id, stmt));
             diagram().add_block_message(std::move(m));
         }
     }
@@ -659,8 +659,8 @@ bool translation_unit_visitor::TraverseWhileStmt(clang::WhileStmt *stmt)
         message m{message_t::kWhile, current_caller_id};
         set_source_location(*stmt, m);
         m.condition_text(condition_text);
-        m.set_comment(clanguml::common::get_expression_comment(
-            source_manager(), *context().get_ast_context(), stmt));
+        m.set_comment(get_expression_comment(source_manager(),
+            *context().get_ast_context(), current_caller_id, stmt));
         diagram().add_block_message(std::move(m));
     }
     RecursiveASTVisitor<translation_unit_visitor>::TraverseWhileStmt(stmt);
@@ -691,8 +691,8 @@ bool translation_unit_visitor::TraverseDoStmt(clang::DoStmt *stmt)
         message m{message_t::kDo, current_caller_id};
         set_source_location(*stmt, m);
         m.condition_text(condition_text);
-        m.set_comment(clanguml::common::get_expression_comment(
-            source_manager(), *context().get_ast_context(), stmt));
+        m.set_comment(get_expression_comment(source_manager(),
+            *context().get_ast_context(), current_caller_id, stmt));
         diagram().add_block_message(std::move(m));
     }
 
@@ -725,8 +725,8 @@ bool translation_unit_visitor::TraverseForStmt(clang::ForStmt *stmt)
         set_source_location(*stmt, m);
         m.condition_text(condition_text);
 
-        m.set_comment(clanguml::common::get_expression_comment(
-            source_manager(), *context().get_ast_context(), stmt));
+        m.set_comment(get_expression_comment(source_manager(),
+            *context().get_ast_context(), current_caller_id, stmt));
 
         diagram().add_block_message(std::move(m));
     }
@@ -754,8 +754,8 @@ bool translation_unit_visitor::TraverseCXXTryStmt(clang::CXXTryStmt *stmt)
         context().enter_trystmt(stmt);
         message m{message_t::kTry, current_caller_id};
         set_source_location(*stmt, m);
-        m.set_comment(clanguml::common::get_expression_comment(
-            source_manager(), *context().get_ast_context(), stmt));
+        m.set_comment(get_expression_comment(source_manager(),
+            *context().get_ast_context(), current_caller_id, stmt));
         diagram().add_block_message(std::move(m));
     }
 
@@ -814,8 +814,8 @@ bool translation_unit_visitor::TraverseCXXForRangeStmt(
         message m{message_t::kFor, current_caller_id};
         set_source_location(*stmt, m);
         m.condition_text(condition_text);
-        m.set_comment(clanguml::common::get_expression_comment(
-            source_manager(), *context().get_ast_context(), stmt));
+        m.set_comment(get_expression_comment(source_manager(),
+            *context().get_ast_context(), current_caller_id, stmt));
         diagram().add_block_message(std::move(m));
     }
 
@@ -841,8 +841,8 @@ bool translation_unit_visitor::TraverseSwitchStmt(clang::SwitchStmt *stmt)
         context().enter_switchstmt(stmt);
         model::message m{message_t::kSwitch, current_caller_id};
         set_source_location(*stmt, m);
-        m.set_comment(clanguml::common::get_expression_comment(
-            source_manager(), *context().get_ast_context(), stmt));
+        m.set_comment(get_expression_comment(source_manager(),
+            *context().get_ast_context(), current_caller_id, stmt));
         diagram().add_block_message(std::move(m));
     }
 
@@ -909,8 +909,8 @@ bool translation_unit_visitor::TraverseConditionalOperator(
         model::message m{message_t::kConditional, current_caller_id};
         set_source_location(*stmt, m);
         m.condition_text(condition_text);
-        m.set_comment(clanguml::common::get_expression_comment(
-            source_manager(), *context().get_ast_context(), stmt));
+        m.set_comment(get_expression_comment(source_manager(),
+            *context().get_ast_context(), current_caller_id, stmt));
         diagram().add_block_message(std::move(m));
     }
 
@@ -960,6 +960,13 @@ bool translation_unit_visitor::VisitCallExpr(clang::CallExpr *expr)
 
     set_source_location(*expr, m);
 
+    process_comment(clanguml::common::get_expression_raw_comment(
+                        source_manager(), *context().get_ast_context(), expr),
+        context().get_ast_context()->getDiagnostics(), m);
+
+    if (m.skip())
+        return true;
+
     // If we're currently inside a lambda expression, set it's id as
     // message source rather then enclosing context
     // Unless the lambda is declared in a function or method call
@@ -1035,8 +1042,8 @@ bool translation_unit_visitor::VisitCallExpr(clang::CallExpr *expr)
     }
 
     if (m.from() > 0 && m.to() > 0) {
-        auto expr_comment = clanguml::common::get_expression_comment(
-            source_manager(), *context().get_ast_context(), expr);
+        auto expr_comment = get_expression_comment(source_manager(),
+            *context().get_ast_context(), context().caller_id(), expr);
         m.set_comment(expr_comment);
 
         if (diagram().sequences().find(m.from()) ==
@@ -2519,4 +2526,21 @@ bool translation_unit_visitor::should_include(
                namespace_{decl->getQualifiedNameAsString()}) &&
         diagram().should_include(common::model::source_file{decl_file});
 }
+
+std::optional<std::string> translation_unit_visitor::get_expression_comment(
+    const clang::SourceManager &sm, const clang::ASTContext &context,
+    const int64_t caller_id, const clang::Stmt *stmt)
+{
+    const auto *raw_comment =
+        clanguml::common::get_expression_raw_comment(sm, context, stmt);
+
+    if (raw_comment == nullptr)
+        return {};
+
+    if (!processed_comments_.emplace(caller_id, raw_comment).second) {
+        return {};
+    }
+
+    return raw_comment->getFormattedText(sm, sm.getDiagnostics());
+}
 } // namespace clanguml::sequence_diagram::visitor

src/sequence_diagram/visitor/translation_unit_visitor.h

@@ -510,6 +510,10 @@ private:
     void pop_message_to_diagram(clang::CallExpr *expr);
     void pop_message_to_diagram(clang::CXXConstructExpr *expr);
 
+    std::optional<std::string> get_expression_comment(
+        const clang::SourceManager &sm, const clang::ASTContext &context,
+        const int64_t caller_id, const clang::Stmt *stmt);
+
     // Reference to the output diagram model
     clanguml::sequence_diagram::model::diagram &diagram_;
 
@@ -546,5 +550,8 @@ private:
     mutable unsigned within_static_variable_declaration_{0};
     mutable std::set<const clang::Expr *>
         already_visited_in_static_declaration_{};
+
+    mutable std::set<std::pair<int64_t, const clang::RawComment *>>
+        processed_comments_;
 };
 } // namespace clanguml::sequence_diagram::visitor

tests/t20001/.clang-uml

@@ -1,5 +1,7 @@
 compilation_database_dir: ..
 output_directory: diagrams
+add_compile_flags:
+  - -fparse-all-comments
 diagrams:
   t20001_sequence:
     type: sequence

tests/t20001/t20001.cc

@@ -63,8 +63,10 @@ int tmain()
     A a;
     B b(a);
 
+    // \uml{note Just add 2 numbers}
     auto tmp = a.add(1, 2);
 
+    // \uml{note[] And now add another 2}
     return b.wrap_add3(tmp, 2, 3);
 }
 }

tests/t20001/test_case.h

@@ -45,6 +45,12 @@ TEST_CASE("t20001", "[test-case][sequence]")
 
         REQUIRE_THAT(src, HasComment("t20001 test diagram of type sequence"));
 
+        REQUIRE_THAT(
+            src, HasMessageComment(_A("tmain()"), "Just add 2 numbers"));
+
+        REQUIRE_THAT(
+            src, HasMessageComment(_A("tmain()"), "And now add another 2"));
+
         save_puml(config.output_directory(), diagram->name + ".puml", src);
     }
     {

tests/t20038/.clang-uml

@@ -0,0 +1,18 @@
+compilation_database_dir: ..
+output_directory: diagrams
+add_compile_flags:
+  - -fparse-all-comments
+diagrams:
+  t20038_sequence:
+    type: sequence
+    glob:
+      - ../../tests/t20038/t20038.cc
+    include:
+      namespaces:
+        - clanguml::t20038
+    from:
+      - function: clanguml::t20038::tmain()
+    generate_message_comments: true
+    message_comment_width: 35
+    using_namespace:
+      - clanguml::t20038

tests/t20038/include/t20038.h

@@ -0,0 +1,14 @@
+#pragma once
+
+namespace clanguml {
+namespace t20038 {
+
+template <typename T> T add_impl(T a, T b) { return a + b; };
+
+template <typename T> T add(T a, T b)
+{
+    // Invoke 'add' implementation
+    return add_impl(a, b);
+};
+}
+}

tests/t20038/t20038.cc

@@ -0,0 +1,91 @@
+#include <future>
+
+#include "include/t20038.h"
+
+namespace clanguml {
+namespace t20038 {
+
+struct A {
+    int a() { return 1; }
+
+    int aa()
+    {
+        int i;
+        // Repeat 10 times
+        for (i = 0; i < 10;) {
+            i += a();
+        }
+        return i;
+    }
+
+    int aaa() { return 3; }
+
+    int aaaa() { return add(4, 4); }
+
+    int aaaaa() { return 5; }
+};
+
+struct B {
+    int b() { return a.a(); }
+
+    int bb() { return a.aa(); }
+
+    int bbb() { return a.aaa(); }
+
+    int bbbb() { return a.aaaa(); }
+
+    int bbbbb() { return a.aaaa(); }
+
+    int wrap(int b) { return b; }
+
+    A a;
+};
+
+int tmain()
+{
+    B b;
+
+    // Nisl purus in mollis nunc sed id semper. Varius vel pharetra vel
+    // turpis. Arcu cursus vitae congue mauris rhoncus. Risus feugiat in
+    // ante metus dictum at tempor. Lacus vel facilisis volutpat est. Auctor
+    // urna nunc id cursus metus aliquam. Diam sit amet nisl suscipit
+    // adipiscing. Potenti nullam ac tortor vitae purus faucibus ornare
+    // suspendisse sed. Lobortis feugiat vivamus at augue eget arcu dictum
+    // varius. Non tellus orci ac auctor.
+    if (true) {
+        auto r = 0;
+        // Repeat 5 times...
+        while (r < 5) {
+            r += b.b();
+        }
+        return r;
+    }
+    else {
+        // ... or just once
+        return 2 * b.b();
+    }
+
+    // \uml{skip}
+    b.bb();
+
+    // TODO: \uml{call B::bbb()}
+    auto bbb_future = std::async(std::launch::deferred, &B::bbb, b);
+
+    bbb_future.wait();
+
+    // This comment should be rendered only once
+    b.wrap(b.bbbb());
+
+    add_impl<double>(2, 2); // What is 2 + 2?
+
+    // This is a generic comment about calling bbbbb()
+    //
+    // \uml{note:some_other_diagram[] This is specific for some_other_diagram}
+    // \uml{note:t20038_sequence[] Calling B::bbbbb()}
+    b.bbbbb();
+
+    // This is a conditional operator
+    return b.bbb() > 5 ? 0 : 1;
+}
+}
+}

tests/t20038/test_case.h

@@ -0,0 +1,127 @@
+/**
+ * tests/t20038/test_case.h
+ *
+ * Copyright (c) 2021-2023 Bartek Kryza <bkryza@gmail.com>
+ *
+ * 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
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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.
+ */
+
+TEST_CASE("t20038", "[test-case][sequence]")
+{
+    auto [config, db] = load_config("t20038");
+
+    auto diagram = config.diagrams["t20038_sequence"];
+
+    REQUIRE(diagram->name == "t20038_sequence");
+
+    auto model = generate_sequence_diagram(*db, diagram);
+
+    REQUIRE(model->name() == "t20038_sequence");
+
+    {
+        auto src = generate_sequence_puml(diagram, *model);
+        AliasMatcher _A(src);
+
+        REQUIRE_THAT(src, StartsWith("@startuml"));
+        REQUIRE_THAT(src, EndsWith("@enduml\n"));
+
+        REQUIRE_THAT(src, HasCall(_A("tmain()"), _A("B"), "b()"));
+
+        REQUIRE_THAT(src, !HasCall(_A("tmain()"), _A("B"), "bb()"));
+
+        // TODO: REQUIRE_THAT(
+        //     src, HasCall(_A("tmain()"), _A("B"), "bbb()"));
+
+        REQUIRE_THAT(src, HasCall(_A("tmain()"), _A("B"), "bbbb()"));
+
+        REQUIRE_THAT(src,
+            HasMessageComment(_A("tmain()"),
+                "This comment should be rendered only\\n"
+                "once"));
+
+        REQUIRE_THAT(src,
+            HasCall(_A("tmain()"), _A("add_impl<double>(double,double)"), ""));
+
+        REQUIRE_THAT(
+            src, HasMessageComment(_A("tmain()"), "What is 2 \\+ 2\\?"));
+
+        REQUIRE_THAT(src,
+            !HasMessageComment(
+                _A("tmain()"), "This is specific for some_other_diagram"));
+
+        REQUIRE_THAT(
+            src, HasMessageComment(_A("tmain()"), "Calling B::bbbbb\\(\\)"));
+
+        REQUIRE_THAT(src, HasCall(_A("tmain()"), _A("B"), "bbbbb()"));
+
+        REQUIRE_THAT(src,
+            HasMessageComment(_A("tmain()"), "This is a conditional operator"));
+
+        save_puml(config.output_directory(), diagram->name + ".puml", src);
+    }
+
+    {
+        auto j = generate_sequence_json(diagram, *model);
+
+        using namespace json;
+
+        save_json(config.output_directory(), diagram->name + ".json", j);
+    }
+
+    {
+        auto src = generate_sequence_mermaid(diagram, *model);
+
+        mermaid::SequenceDiagramAliasMatcher _A(src);
+        using mermaid::HasCall;
+        using mermaid::HasCallInControlCondition;
+        using mermaid::HasMessageComment;
+
+        REQUIRE_THAT(src, HasCall(_A("tmain()"), _A("B"), "b()"));
+
+        REQUIRE_THAT(src, !HasCall(_A("tmain()"), _A("B"), "bb()"));
+
+        // TODO: REQUIRE_THAT(
+        //     src, HasCall(_A("tmain()"), _A("B"), "bbb()"));
+
+        REQUIRE_THAT(src, HasCall(_A("tmain()"), _A("B"), "bbbb()"));
+
+        REQUIRE_THAT(src,
+            HasMessageComment(_A("tmain()"),
+                "This comment should be rendered only<br/>"
+                "once"));
+
+        REQUIRE_THAT(src,
+            HasCall(_A("tmain()"), _A("add_impl<double>(double,double)"), ""));
+
+        REQUIRE_THAT(
+            src, HasMessageComment(_A("tmain()"), "What is 2 \\+ 2\\?"));
+
+        REQUIRE_THAT(src,
+            !HasMessageComment(
+                _A("tmain()"), "This is specific for some_other_diagram"));
+
+        REQUIRE_THAT(
+            src, HasMessageComment(_A("tmain()"), "Calling B::bbbbb\\(\\)"));
+
+        REQUIRE_THAT(src, HasCall(_A("tmain()"), _A("B"), "bbbbb()"));
+
+        REQUIRE_THAT(src,
+            !HasMessageComment(
+                _A("tmain()"), "This is specific for some_other_diagram"));
+
+        REQUIRE_THAT(
+            src, HasMessageComment(_A("tmain()"), "Calling B::bbbbb\\(\\)"));
+
+        save_mermaid(config.output_directory(), diagram->name + ".mmd", src);
+    }
+}

tests/test_cases.cc

@@ -429,6 +429,7 @@ using namespace clanguml::test::matchers;
 #include "t20035/test_case.h"
 #include "t20036/test_case.h"
 #include "t20037/test_case.h"
+#include "t20038/test_case.h"
 
 ///
 /// Package diagram tests

tests/test_cases.yaml

@@ -310,6 +310,9 @@ test_cases:
     - name: t20037
       title: Test case checking if activities in static variable declarations appear only once
       description:
+    - name: t20038
+      title: Sequence diagram comment decorator test case
+      description:
   Package diagrams:
     - name: t30001
       title: Basic package diagram test case