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

lib/cppcheck.cpp

@@ -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)) {
+                    invalidConfigurationMessage(file.spath(), tokensP.file(output->location), config, *output);
+                }
+            }
 
             if (configurations.size() > maxConfigs)
                 tooManyConfigsError(Path::toNativeSeparators(file.spath()), configurations.size());
@@ -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)
@@ -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;

lib/cppcheck.h

@@ -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;
 

test/testcppcheck.cpp

@@ -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);
     }
 
@@ -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;
@@ -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)
@@ -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,