cppcheck-opensource · firewave · Mar 18, 2025 · Jan 3, 2025
diff --git a/cli/cmdlineparser.cpp b/cli/cmdlineparser.cpp
@@ -572,6 +572,9 @@ CmdLineParser::Result CmdLineParser::parseFromArgs(int argc, const char* const a
             mSettings.checkLibrary = true;
         }
 
+        else if (std::strcmp(argv[i], "--check-unused-templates") == 0)
+            mSettings.checkUnusedTemplates = true;
+
         else if (std::strncmp(argv[i], "--check-version=", 16) == 0) {
             if (!loadCppcheckCfg())
                 return Result::Fail;
@@ -1007,6 +1010,9 @@ CmdLineParser::Result CmdLineParser::parseFromArgs(int argc, const char* const a
         else if (std::strcmp(argv[i], "--no-check-headers") == 0)
             mSettings.checkHeaders = false;
 
+        else if (std::strcmp(argv[i], "--no-check-unused-templates") == 0)
+            mSettings.checkUnusedTemplates = false;
+
         // undocumented option for usage in Python tests to indicate that no build dir should be injected
         else if (std::strcmp(argv[i], "--no-cppcheck-build-dir") == 0) {
             mSettings.buildDir.clear();

diff --git a/lib/settings.h b/lib/settings.h
@@ -152,7 +152,7 @@ class CPPCHECKLIB WARN_UNUSED Settings {
     std::set<std::string> checkUnknownFunctionReturn; // TODO: move to Library?
 
     /** Check unused/uninstantiated templates */
-    bool checkUnusedTemplates = true; // TODO: CLI
+    bool checkUnusedTemplates = true;
 
     /** Use Clang */
     bool clang{};

diff --git a/test/cli/other_test.py b/test/cli/other_test.py
@@ -3166,7 +3166,6 @@ def test_dir_ignore(tmp_path):
     assert_cppcheck(args, ec_exp=0, err_exp=[], out_exp=out_lines, cwd=str(tmp_path))
 
 
-
 def test_check_headers(tmp_path):
     test_file_h = tmp_path / 'test.h'
     with open(test_file_h, 'wt') as f:
@@ -3199,7 +3198,6 @@ def test_check_headers(tmp_path):
     assert stderr.splitlines() == []  # no error since the header is not checked
 
 
-
 def test_unique_error(tmp_path):  # #6366
     test_file = tmp_path / 'test.c'
     with open(test_file, 'wt') as f:
@@ -3224,4 +3222,151 @@ def test_unique_error(tmp_path):  # #6366
     assert stderr.splitlines() == [
         "{}:4:13: error: Array 'm[9]' accessed at index 9, which is out of bounds. [arrayIndexOutOfBounds]".format(test_file),
         "{}:4:21: error: Array 'm[9]' accessed at index 9, which is out of bounds. [arrayIndexOutOfBounds]".format(test_file)
-    ]
+    ]
+
+
+def test_check_unused_templates_class(tmp_path):
+    test_file_h = tmp_path / 'test.h'
+    with open(test_file_h, 'wt') as f:
+        f.write(
+"""template<class T>
+class HdrCl1
+{
+    HdrCl1()
+    {
+        (void)(*((int*)0));
+    }
+};
+
+template<typename T>
+class HdrCl2
+{
+    HdrCl2()
+    {
+        (void)(*((int*)0));
+    }
+};
+
+template<class T>
+struct HdrSt1
+{
+    HdrSt1()
+    {
+        (void)(*((int*)0));
+    }
+};
+
+template<typename T>
+struct HdrSt2
+{
+    HdrSt2()
+    {
+        (void)(*((int*)0));
+    }
+};
+""")
+
+    test_file = tmp_path / 'test.cpp'
+    with open(test_file, 'wt') as f:
+        f.write(
+"""#include "test.h"
+
+template<class T>
+class Cl1
+{
+    CL1()
+    {
+        (void)(*((int*)0));
+    }
+};
+
+template<typename T>
+class Cl2
+{
+    Cl2()
+    {
+        (void)(*((int*)0));
+    }
+};
+
+template<class T>
+struct St1
+{
+    St1()
+    {
+        (void)(*((int*)0));
+    }
+};
+
+template<typename T>
+struct St2
+{
+    St2()
+    {
+        (void)(*((int*)0));
+    }
+};
+
+void f() {}
+""")
+
+    args = [
+        '-q',
+        '--template=simple',
+        '--no-check-unused-templates',
+        str(test_file)
+    ]
+    exitcode, stdout, stderr = cppcheck(args)
+    assert exitcode == 0, stdout
+    assert stdout.splitlines() == []
+    assert stderr.splitlines() == []  # no error since the unused templates are not being checked
+
+
+@pytest.mark.xfail(strict=True)  # TODO: only the first unused templated function is not being checked
+def test_check_unused_templates_func(tmp_path):  # #13714
+    test_file_h = tmp_path / 'test.h'
+    with open(test_file_h, 'wt') as f:
+        f.write(
+"""template<class T>
+void f_t_hdr_1()
+{
+    (void)(*((int*)0));
+}
+
+template<typename T>
+void f_t_hdr_2()
+{
+    (void)(*((int*)0));
+}
+""")
+
+    test_file = tmp_path / 'test.cpp'
+    with open(test_file, 'wt') as f:
+        f.write(
+"""#include "test.h"
+
+template<class T>
+void f_t_1()
+{
+    (void)(*((int*)0));
+}
+
+template<typename T>
+void f_t_2()
+{
+    (void)(*((int*)0));
+}
+
+void f() {}
+""")
+
+    args = [
+        '-q',
+        '--template=simple',
+        '--no-check-unused-templates',
+        str(test_file)
+    ]
+    exitcode, stdout, stderr = cppcheck(args)
+    assert exitcode == 0, stdout
+    assert stdout.splitlines() == []
+    assert stderr.splitlines() == []  # no error since the unused templates are not being checked
diff --git a/test/testcmdlineparser.cpp b/test/testcmdlineparser.cpp
@@ -445,6 +445,9 @@ class TestCmdlineParser : public TestFixture {
         TEST_CASE(noCheckHeaders);
         TEST_CASE(noCheckHeaders2);
         TEST_CASE(filesdir);
+        TEST_CASE(checkUnusedTemplates);
+        TEST_CASE(noCheckUnusedTemplates);
+        TEST_CASE(noCheckUnusedTemplates);
 
         TEST_CASE(ignorepaths1);
         TEST_CASE(ignorepaths2);
@@ -3024,6 +3027,27 @@ class TestCmdlineParser : public TestFixture {
 #endif
     }
 
+    void checkUnusedTemplates() {
+        REDIRECT;
+        const char * const argv[] = {"cppcheck", "--check-unused-templates", "file.cpp"};
+        ASSERT_EQUALS_ENUM(CmdLineParser::Result::Success, parser->parseFromArgs(3, argv));
+        ASSERT_EQUALS(true, settings->checkUnusedTemplates);
+    }
+
+    void noCheckUnusedTemplates() {
+        REDIRECT;
+        const char * const argv[] = {"cppcheck", "--no-check-unused-templates", "file.cpp"};
+        ASSERT_EQUALS_ENUM(CmdLineParser::Result::Success, parser->parseFromArgs(3, argv));
+        ASSERT_EQUALS(false, settings->checkUnusedTemplates);
+    }
+
+    void noCheckUnusedTemplates2() {
+        REDIRECT;
+        const char * const argv[] = {"cppcheck", "--check-unused-templates", "--no-check-unused-templates", "file.cpp"};
+        ASSERT_EQUALS_ENUM(CmdLineParser::Result::Success, parser->parseFromArgs(4, argv));
+        ASSERT_EQUALS(false, settings->checkUnusedTemplates);
+    }
+
     void ignorepaths1() {
         REDIRECT;
         const char * const argv[] = {"cppcheck", "-isrc", "file.cpp"};