From 751bcd7cf9f538c9f1a77baa59a3075698ff4b7c Mon Sep 17 00:00:00 2001
From: firewave <firewave@users.noreply.github.com>
Date: Mon, 13 Jan 2025 14:25:17 +0100
Subject: [PATCH] added CLI option `--debug-clang-ast` to print Clang AST

---
 cli/cmdlineparser.cpp         |  4 ++++
 lib/cppcheck.cpp              |  4 ++++
 lib/settings.h                |  3 +++
 test/cli/clang-import_test.py | 22 ++++++++++++++++++++++
 test/testcmdlineparser.cpp    |  8 ++++++++
 5 files changed, 41 insertions(+)

diff --git a/cli/cmdlineparser.cpp b/cli/cmdlineparser.cpp
index 20b39179e8e..1bbfc5afa1b 100644
--- a/cli/cmdlineparser.cpp
+++ b/cli/cmdlineparser.cpp
@@ -614,6 +614,10 @@ CmdLineParser::Result CmdLineParser::parseFromArgs(int argc, const char* const a
                 mSettings.cppHeaderProbe = true;
             }
 
+            // Show debug warnings for lookup for configuration files
+            else if (std::strcmp(argv[i], "--debug-clang-ast") == 0)
+                mSettings.debugClangAst = true;
+
             // Show --debug output after the first simplifications
             else if (std::strcmp(argv[i], "--debug") == 0 ||
                      std::strcmp(argv[i], "--debug-normal") == 0)
diff --git a/lib/cppcheck.cpp b/lib/cppcheck.cpp
index e7ae9b14399..3eb4b96af6e 100644
--- a/lib/cppcheck.cpp
+++ b/lib/cppcheck.cpp
@@ -684,6 +684,10 @@ unsigned int CppCheck::checkClang(const FileWithDetails &file)
         return 0; // TODO: report as failure?
     }
 
+    if (mSettings.debugClangAst) {
+        std::cout << output2 << std::endl;
+    }
+
     if (output2.find("TranslationUnitDecl") == std::string::npos) {
         // TODO: report as proper error
         std::cerr << "Failed to execute '" << exe << " " << args2 << " " << redirect2 << "' - (no TranslationUnitDecl in output)" << std::endl;
diff --git a/lib/settings.h b/lib/settings.h
index 9afb9431a6f..21c8f9acdaf 100644
--- a/lib/settings.h
+++ b/lib/settings.h
@@ -178,6 +178,9 @@ class CPPCHECKLIB WARN_UNUSED Settings {
     /** @brief Are we running from DACA script? */
     bool daca{};
 
+    /** @brief Is --debug-clang-ast given? */
+    bool debugClangAst{};
+
     /** @brief Internal: Is --debug-lookup or --debug-lookup=all given? */
     bool debuglookup{};
 
diff --git a/test/cli/clang-import_test.py b/test/cli/clang-import_test.py
index 4e0b7e09e48..c4f2fb7d113 100644
--- a/test/cli/clang-import_test.py
+++ b/test/cli/clang-import_test.py
@@ -239,3 +239,25 @@ def test_cmd_std_c_enforce_alias_2(tmp_path):  # #13128/#13129/#13130
 
 def test_cmd_std_cpp_enforce_alias(tmp_path):  # #13128/#13129/#13130
     __test_cmd(tmp_path, 'test.c',['--language=c++', '--std=gnu99', '--std=gnu++11'], '-x c++ -std=gnu++11')
+
+
+def test_debug_ast(tmp_path):
+    test_file = tmp_path / 'test.c'
+    with open(test_file, 'wt') as f:
+        f.write(
+"""
+void f() {}
+""")
+
+    args = [
+        '-q',
+        '--clang',
+        '--debug-clang-ast',
+        str(test_file)
+    ]
+
+    exitcode, stdout, stderr = cppcheck(args)
+    assert exitcode == 0, stderr if not stdout else stdout
+    assert stderr == ''
+    assert stdout.startswith('TranslationUnitDecl'), stdout
+    assert stdout.find(str(test_file)) != -1, stdout
\ No newline at end of file
diff --git a/test/testcmdlineparser.cpp b/test/testcmdlineparser.cpp
index e854400c946..ce863a96a41 100644
--- a/test/testcmdlineparser.cpp
+++ b/test/testcmdlineparser.cpp
@@ -422,6 +422,7 @@ class TestCmdlineParser : public TestFixture {
         TEST_CASE(maxTemplateRecursion);
         TEST_CASE(maxTemplateRecursionMissingCount);
         TEST_CASE(emitDuplicates);
+        TEST_CASE(debugClangAst);
 
         TEST_CASE(ignorepaths1);
         TEST_CASE(ignorepaths2);
@@ -2907,6 +2908,13 @@ class TestCmdlineParser : public TestFixture {
         ASSERT_EQUALS(true, settings->emitDuplicates);
     }
 
+    void debugClangAst() {
+        REDIRECT;
+        const char * const argv[] = {"cppcheck", "--debug-clang-ast", "file.cpp"};
+        ASSERT_EQUALS_ENUM(CmdLineParser::Result::Success, parser->parseFromArgs(3, argv));
+        ASSERT_EQUALS(true, settings->debugClangAst);
+    }
+
     void ignorepaths1() {
         REDIRECT;
         const char * const argv[] = {"cppcheck", "-isrc", "file.cpp"};