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Explain skipped error-directive configurations in --check-config #8889

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Explain skipped error-directive configurations in --check-config #8889

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7da51b8
Explain configurations skipped by error directives in check-config
KiritoYG Sep 24, 2026
f1506fe
Match Uncrustify continuation indentation
KiritoYG Sep 24, 2026
f35aa31
Avoid copying configuration message in regression test
KiritoYG Sep 24, 2026
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40 changes: 38 additions & 2 deletions lib/cppcheck.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1106,8 +1106,16 @@ unsigned int CppCheck::checkInternal(const FileWithDetails& file, const std::str
}

if (mSettings.checkConfiguration) {
for (const std::string &config : configurations)
(void)preprocessor.getcode(config, files, false);
for (const std::string &config : configurations) {
simplecpp::OutputList outputList_cfg;
const simplecpp::TokenList tokensP = preprocessor.preprocess(config, files, outputList_cfg);
const simplecpp::Output* output = preprocessor.handleErrors(outputList_cfg);
// Other failures, and #error with explicit defines, are already reported by handleErrors.
if (output && output->type == simplecpp::Output::ERROR && startsWith(output->msg, "#error") &&
(mSettings.userDefines.empty() || mSettings.force)) {
Comment on lines +1114 to +1115

@danmar danmar Oct 1, 2026

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This is an AI review. Take it with a grain of salt and feel free to reject it by resolving the comment.

The behavior looks right to me. I tried the test case from the PR via the CLI: --check-config now reports invalidConfiguration for FEATURE=FEATURE, -DFEATURE without --force still gives only the existing preprocessorErrorDirective, and normal analysis is unchanged.

One maintainability concern: (mSettings.userDefines.empty() || mSettings.force) is the negation of showerror in Preprocessor::handleErrors(), and startsWith(output->msg, "#error") repeats the check in Preprocessor::reportOutput(). If one of those is changed later, this will silently start producing duplicates or missing messages. Maybe let the preprocessor tell whether it already reported the #error (for example, a small helper that returns showerror, or a flag/out-parameter from handleErrors()) instead of re-deriving the condition here?

Minor: the location building in invalidConfigurationMessage() (fromNativeSeparators + relativePaths) duplicates Preprocessor::error().

invalidConfigurationMessage(file.spath(), tokensP.file(output->location), config, *output);
}
}

if (configurations.size() > maxConfigs)
tooManyConfigsError(Path::toNativeSeparators(file.spath()), configurations.size());
Expand Down Expand Up @@ -1752,6 +1760,33 @@ void CppCheck::purgedConfigurationMessage(const std::string &file, const std::st
mErrorLogger.reportErr(errmsg);
}

void CppCheck::invalidConfigurationMessage(const std::string& file0, const std::string& file,
const std::string& configuration, const simplecpp::Output& output)
{
std::list<ErrorMessage::FileLocation> locations;
if (!file.empty()) {
std::string filename = Path::fromNativeSeparators(file);
if (mSettings.relativePaths)
filename = Path::getRelativePath(filename, mSettings.basePaths);
locations.emplace_back(filename, output.location.line, output.location.col);
}

// preprocess() also applies userDefines; include them in the configuration shown to the user.
std::string effectiveConfig = mSettings.userDefines;
const std::vector<std::string> userDefines = split(mSettings.userDefines, ";");
for (const std::string& define : split(configuration, ";")) {
if (define.empty() || std::find(userDefines.cbegin(), userDefines.cend(), define) != userDefines.cend())
continue;
if (!effectiveConfig.empty())
effectiveConfig += ';';
effectiveConfig += define;
}

mErrorLogger.reportErr(ErrorMessage(std::move(locations), file0, Severity::information,
"The configuration '" + effectiveConfig + "' was not checked because of a preprocessor error: " + output.msg,
"invalidConfiguration", Certainty::normal));
}

//---------------------------------------------------------------------------

void CppCheck::getErrorMessages(ErrorLogger &errorlogger)
Expand All @@ -1763,6 +1798,7 @@ void CppCheck::getErrorMessages(ErrorLogger &errorlogger)
CppCheck cppcheck(settings, supprs, errorlogger, nullptr, true, nullptr);
cppcheck.purgedConfigurationMessage("","");
cppcheck.tooManyConfigsError("",0U);
cppcheck.invalidConfigurationMessage("", "", "", simplecpp::Output(simplecpp::Output::ERROR, {}, "#error"));
// TODO: add functions to get remaining error messages

Settings s;
Expand Down
2 changes: 2 additions & 0 deletions lib/cppcheck.h
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Original file line number Diff line number Diff line change
Expand Up @@ -146,6 +146,8 @@ class CPPCHECKLIB CppCheck {

private:
void purgedConfigurationMessage(const std::string &file, const std::string& configuration);
void invalidConfigurationMessage(const std::string& file0, const std::string& file,
const std::string& configuration, const simplecpp::Output& output);

bool isPremiumCodingStandardId(const std::string& id) const;

Expand Down
105 changes: 105 additions & 0 deletions test/testcppcheck.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -101,6 +101,13 @@ class TestCppcheck : public TestFixture {
TEST_CASE(checkPlistOutput);
TEST_CASE(premiumResultsCache);
TEST_CASE(purgedConfiguration);
TEST_CASE(checkConfigurationInvalid);
TEST_CASE(checkConfigurationValid);
TEST_CASE(checkConfigurationSuppression);
TEST_CASE(checkConfigurationExplicitError);
TEST_CASE(checkConfigurationCombinedDefines);
TEST_CASE(checkConfigurationNormalAnalysis);
TEST_CASE(checkConfigurationHeader);
TEST_CASE(recheckInclude);
}

Expand All @@ -126,6 +133,7 @@ class TestCppcheck : public TestFixture {
bool foundTooManyConfigs = false;
bool foundMissingInclude = false; // #11984
bool foundMissingIncludeSystem = false; // #11984
bool foundInvalidConfiguration = false;
for (const std::string & it : errorLogger.ids) {
if (it == "purgedConfiguration")
foundPurgedConfiguration = true;
Expand All @@ -135,11 +143,14 @@ class TestCppcheck : public TestFixture {
foundMissingInclude = true;
else if (it == "missingIncludeSystem")
foundMissingIncludeSystem = true;
else if (it == "invalidConfiguration")
foundInvalidConfiguration = true;
}
ASSERT(foundPurgedConfiguration);
ASSERT(foundTooManyConfigs);
ASSERT(foundMissingInclude);
ASSERT(foundMissingIncludeSystem);
ASSERT(foundInvalidConfiguration);
}

static std::string exename_(const std::string& exe)
Expand Down Expand Up @@ -639,6 +650,100 @@ class TestCppcheck : public TestFixture {
it->toString(false, templateFormat, ""));
}

static const char* invalidConfigurationCode() {
return "#ifndef PLATFORM\n"
"#error Select PLATFORM\n"
"#endif\n"
"int base;\n"
"#ifdef FEATURE\n"
"int feature;\n"
"#endif\n";
}

std::list<ErrorMessage> configurationMessages(const char* code, const Settings& settings, const char* suppression = nullptr) const {
const ScopedFile source("check-config.c", code);
Settings configuredSettings = settings;
configuredSettings.templateFormat = templateFormat;
Suppressions supprs;
if (suppression)
ASSERT_EQUALS("", supprs.nomsg.addSuppressionLine(suppression));
ErrorLogger2 errorLogger;
CppCheck cppcheck(configuredSettings, supprs, errorLogger, nullptr, true, {});
cppcheck.check(FileWithDetails(source.path(), Path::identify(source.path(), false), 0));
errorLogger.errmsgs.remove_if([](const ErrorMessage& msg) {
return msg.id == "logChecker";
});
return errorLogger.errmsgs;
}

void checkConfigurationInvalid() const {
// Trac #6672: FEATURE is considered independently of the required PLATFORM.
const auto settings = dinit(Settings, $.checkConfiguration = true, $.templateFormat = templateFormat);
const auto messages = configurationMessages(invalidConfigurationCode(), settings);
ASSERT_EQUALS(1, messages.size());
const ErrorMessage& msg = messages.front();
ASSERT_EQUALS("invalidConfiguration", msg.id);
ASSERT(msg.severity == Severity::information);
ASSERT_EQUALS("check-config.c", msg.file0);
ASSERT_EQUALS(1, msg.callStack.size());
ASSERT_EQUALS("check-config.c", msg.callStack.back().getfile(false));
ASSERT_EQUALS(2, msg.callStack.back().line);
ASSERT(msg.shortMessage().find("FEATURE") != std::string::npos);
ASSERT(msg.shortMessage().find("#error Select PLATFORM") != std::string::npos);
}

void checkConfigurationValid() const {
const auto settings = dinit(Settings, $.checkConfiguration = true, $.userDefines = "PLATFORM=1");
ASSERT(configurationMessages(invalidConfigurationCode(), settings).empty());

const auto automaticSettings = dinit(Settings, $.checkConfiguration = true);
ASSERT(configurationMessages("#if 0\n#error inactive\n#endif\nint value;\n", automaticSettings).empty());
ASSERT(configurationMessages("#ifdef FEATURE\nint feature;\n#endif\nint value;\n", automaticSettings).empty());
}

void checkConfigurationSuppression() const {
const auto settings = dinit(Settings, $.checkConfiguration = true);
ASSERT(configurationMessages(invalidConfigurationCode(), settings, "invalidConfiguration").empty());
}

void checkConfigurationExplicitError() const {
const auto settings = dinit(Settings, $.checkConfiguration = true, $.userDefines = "FEATURE=1");
const auto messages = configurationMessages(invalidConfigurationCode(), settings);
ASSERT_EQUALS(1, messages.size());
ASSERT_EQUALS("preprocessorErrorDirective", messages.front().id);
ASSERT(messages.front().severity == Severity::error);
}

void checkConfigurationCombinedDefines() const {
const auto settings = dinit(Settings, $.checkConfiguration = true, $.force = true, $.userDefines = "EXTRA=7");
const auto messages = configurationMessages(invalidConfigurationCode(), settings);
ASSERT_EQUALS(1, messages.size());
ASSERT_EQUALS("invalidConfiguration", messages.front().id);
const std::string& message = messages.front().shortMessage();
ASSERT(message.find("EXTRA=7;FEATURE") != std::string::npos);
ASSERT(message.find("EXTRA=7", message.find("EXTRA=7") + 1) == std::string::npos);
}

void checkConfigurationNormalAnalysis() const {
const auto settings = dinit(Settings, $.force = true, $.severity.enable(Severity::information));
ASSERT(configurationMessages(invalidConfigurationCode(), settings).empty());
}

void checkConfigurationHeader() const {
const ScopedFile header("config-error.h", "#ifndef PLATFORM\n#error Select PLATFORM\n#endif\n");
const auto settings = dinit(Settings, $.checkConfiguration = true);
const auto messages = configurationMessages("#include \"config-error.h\"\n#ifdef FEATURE\nint feature;\n#endif\n", settings);
// Both the empty and FEATURE configurations fail in the included header.
ASSERT_EQUALS(2, messages.size());
ASSERT(messages.front().shortMessage() != messages.back().shortMessage());
for (const ErrorMessage& message : messages) {
ASSERT_EQUALS("invalidConfiguration", message.id);
ASSERT_EQUALS("check-config.c", message.file0);
ASSERT_EQUALS("config-error.h", message.callStack.back().getfile(false));
ASSERT_EQUALS(2, message.callStack.back().line);
}
}

void recheckInclude() const
{
const auto settings = dinit(Settings,
Expand Down