Properly handle in-progress C++ standards when invoking Cppcheck // Resolve #3944 (#4070)

HISTORY.rst

@@ -14,6 +14,7 @@ PlatformIO Core 5
 - Allowed to override a default library builder via a new ``builder`` field in a ``build`` group of `library.json <https://docs.platformio.org/page/librarymanager/config.html#build>`__ manifest (`issue #3957 <https://github.com/platformio/platformio-core/issues/3957>`_)
 - Fixed a "KeyError: Invalid board option 'build.cpu'" when using a precompiled library with a board that does not have a CPU field in the manifest (`issue #4056 <https://github.com/platformio/platformio-core/issues/4056>`_)
 - Fixed a "FileExist" error when the `platformio ci <https://docs.platformio.org/en/latest/userguide/cmd_ci.html>`__ command is used in pair with the ``--keep-build-dir`` option (`issue #4011 <https://github.com/platformio/platformio-core/issues/4011>`_)
+- Fixed an issue with draft values of C++ language standards that broke static analysis via Cppcheck (`issue #3944 <https://github.com/platformio/platformio-core/issues/3944>`_)
 
 5.2.0 (2021-09-13)
 ~~~~~~~~~~~~~~~~~~

platformio/commands/check/tools/cppcheck.py

@@ -141,10 +141,11 @@ class CppcheckCheckTool(CheckToolBase):
 
         build_flags = self.cxx_flags if language == "c++" else self.cc_flags
 
-        for flag in build_flags:
-            if "-std" in flag:
-                # Standards with GNU extensions are not allowed
-                cmd.append("-" + flag.replace("gnu", "c"))
+        if not self.is_flag_set("--std", flags):
+            # Try to guess the standard version from the build flags
+            for flag in build_flags:
+                if "-std" in flag:
+                    cmd.append("-" + self.convert_language_standard(flag))
 
         cmd.extend(
             ["-D%s" % d for d in self.cpp_defines + self.toolchain_defines[language]]
@@ -224,6 +225,21 @@ class CppcheckCheckTool(CheckToolBase):
         # Cppcheck is configured to return '3' if a defect is found
         return cmd_result["returncode"] in (0, 3)
 
+    @staticmethod
+    def convert_language_standard(flag):
+        cpp_standards_map = {
+            "0x": "11",
+            "1y": "14",
+            "1z": "17",
+            "2a": "20",
+        }
+
+        standard = flag[-2:]
+        # Note: GNU extensions are not supported and converted to regular standards
+        return flag.replace("gnu", "c").replace(
+            standard, cpp_standards_map.get(standard, standard)
+        )
+
     def check(self, on_defect_callback=None):
         self._on_defect_callback = on_defect_callback
 

tests/commands/test_check.py

@@ -15,7 +15,6 @@
 # pylint: disable=redefined-outer-name
 
 import json
-import sys
 from os.path import isfile, join
 
 import pytest
@@ -132,6 +131,47 @@ def test_check_language_standard_definition_passed(clirunner, tmpdir):
     assert "--std=c++17" in result.output
 
 
+def test_check_language_standard_option_is_converted(clirunner, tmpdir):
+    config = (
+        DEFAULT_CONFIG
+        + """
+build_flags = -std=gnu++1y
+    """
+    )
+    tmpdir.join("platformio.ini").write(config)
+    tmpdir.mkdir("src").join("main.cpp").write(TEST_CODE)
+    result = clirunner.invoke(cmd_check, ["--project-dir", str(tmpdir), "-v"])
+
+    assert "--std=c++14" in result.output
+
+
+def test_check_language_standard_is_prioritized_over_build_flags(clirunner, tmpdir):
+    config = (
+        DEFAULT_CONFIG
+        + """
+check_flags = --std=c++03
+build_flags = -std=c++17
+    """
+    )
+    tmpdir.join("platformio.ini").write(config)
+    tmpdir.mkdir("src").join("main.cpp").write(TEST_CODE)
+    result = clirunner.invoke(cmd_check, ["--project-dir", str(tmpdir), "-v"])
+
+    assert "--std=c++03" in result.output
+    assert "--std=c++17" not in result.output
+
+
+def test_check_language_standard_for_c_language(clirunner, tmpdir):
+    config = DEFAULT_CONFIG + "\nbuild_flags = -std=c11"
+    tmpdir.join("platformio.ini").write(config)
+    tmpdir.mkdir("src").join("main.c").write(TEST_CODE)
+    result = clirunner.invoke(cmd_check, ["--project-dir", str(tmpdir), "-v"])
+
+    assert "--std=c11" in result.output
+    assert "__STDC_VERSION__=201112L" in result.output
+    assert "__cplusplus" not in result.output
+
+
 def test_check_severity_threshold(clirunner, validate_cliresult, check_dir):
     result = clirunner.invoke(
         cmd_check, ["--project-dir", str(check_dir), "--severity=high"]
@@ -451,12 +491,11 @@ int main() {
 """
     )
 
-    frameworks = ["arduino", "stm32cube"]
-    if sys.version_info[0] == 3:
-        # Zephyr only supports Python 3
-        frameworks.append("zephyr")
-
-    for framework in frameworks:
+    for framework in (
+        "arduino",
+        "stm32cube",
+        "zephyr",
+    ):
         for tool in ("cppcheck", "clangtidy", "pvs-studio"):
             tmpdir.join("platformio.ini").write(config % (framework, tool))
             result = clirunner.invoke(cmd_check, ["--project-dir", str(tmpdir)])