Preprocessor: run paths of some error messages through Path::simplifyPath()

teach Path::simplifyPath() to recursively remove "./././" from beginning of paths.

lib/path.cpp

@@ -63,8 +63,7 @@ std::string Path::simplifyPath(std::string originalPath)
     const bool isUnc = originalPath.size() > 2 && originalPath[0] == '/' && originalPath[1] == '/';
 
     // Remove ./, .//, ./// etc. at the beginning
-    if (originalPath.size() > 2 && originalPath[0] == '.' &&
+    while (originalPath.size() > 2 && originalPath[0] == '.' && originalPath[1] == '/') { // remove "./././"
-        originalPath[1] == '/') {
         size_t toErase = 2;
         for (std::size_t i = 2; i < originalPath.size(); i++) {
             if (originalPath[i] == '/')

lib/preprocessor.cpp

@@ -485,7 +485,7 @@ std::string Preprocessor::removeComments(const std::string &str, const std::stri
             errmsg.str("");
             errmsg << "The code contains unhandled characters " << info << ". Checking continues, but do not expect valid results.\n"
                    << "The code contains characters that are unhandled " << info << ". Neither unicode nor extended ASCII are supported. Checking continues, but do not expect valid results.";
-            writeError(filename, lineno, _errorLogger, "unhandledCharacters", errmsg.str());
+            writeError(Path::simplifyPath(filename), lineno, _errorLogger, "unhandledCharacters", errmsg.str());
         }
 
         if (_settings.terminated())
@@ -1914,7 +1914,7 @@ std::string Preprocessor::getcode(const std::string &filedata, const std::string
         // #error => return ""
         if (match && line.compare(0, 6, "#error") == 0) {
             if (!_settings.userDefines.empty() && !_settings._force) {
-                error(filenames.top(), lineno, line);
+                error(Path::simplifyPath(filenames.top()), lineno, line);
             }
             return "";
         }
@@ -3044,7 +3044,7 @@ std::string Preprocessor::expandMacros(const std::string &code, std::string file
                     ++pos;
 
                     if (pos >= line.size()) {
-                        writeError(filename,
+                        writeError(Path::simplifyPath(filename),
                                    linenr + tmpLinenr,
                                    errorLogger,
                                    "noQuoteCharPair",

test/testpreprocessor.cpp

@@ -300,6 +300,9 @@ private:
         TEST_CASE(invalid_ifs); // #5909
 
         TEST_CASE(garbage);
+
+        TEST_CASE(wrongPathOnUnicodeError); // see #6773
+        TEST_CASE(wrongPathOnErrorDirective);
     }
 
     std::string preprocessorRead(const char* code) {
@@ -3711,6 +3714,27 @@ private:
         std::map<std::string, std::string> actual;
         preprocess(filedata, actual);
     }
+
+    void wrongPathOnUnicodeError() {
+        const char filedata[] = "#file ././test.c\n"
+                                "extern int 🌷;\n";
+        preprocessorRead(filedata);
+        ASSERT_EQUALS("[test.c:2]: (error) The code contains unhandled characters (character code = 0xf0). Checking continues, but do not expect valid results.\n"
+                      "[test.c:2]: (error) The code contains unhandled characters (character code = 0x9f). Checking continues, but do not expect valid results.\n"
+                      "[test.c:2]: (error) The code contains unhandled characters (character code = 0x8c). Checking continues, but do not expect valid results.\n"
+                      "[test.c:2]: (error) The code contains unhandled characters (character code = 0xb7). Checking continues, but do not expect valid results.\n", errout.str());
+    }
+
+    void wrongPathOnErrorDirective() {
+        errout.str("");
+        Settings settings;
+        settings.userDefines = "foo";
+        Preprocessor preprocessor(settings, this);
+        const std::string code("#error hello world!\n");
+        preprocessor.getcode(code, "X", "./././test.c");
+        ASSERT_EQUALS("[test.c:1]: (error) #error hello world!\n", errout.str());
+    }
+
 };
 
 REGISTER_TEST(TestPreprocessor)