Check if --cppcheck-build-dir exists (#5254)

Cppcheck does not report that cppcheck build dir does not exist and also
does not report any write issues to the non-existent directory.

This means that cppcheck build dir is actually not used.

We should either create the directory or fail.

cli/cmdlineparser.cpp

@@ -285,10 +285,14 @@ bool CmdLineParser::parseFromArgs(int argc, const char* const argv[])
             }
 
             else if (std::strncmp(argv[i], "--cppcheck-build-dir=", 21) == 0) {
-                // TODO: bail out when the folder does not exist? will silently do nothing
                 mSettings.buildDir = Path::fromNativeSeparators(argv[i] + 21);
                 if (endsWith(mSettings.buildDir, '/'))
                     mSettings.buildDir.pop_back();
+
+                if (!Path::directoryExists(mSettings.buildDir)) {
+                    printError("Directory '" + mSettings.buildDir + "' specified by --cppcheck-build-dir argument has to be existent.");
+                    return false;
+                }
             }
 
             // Show --debug output after the first simplifications

lib/path.cpp

@@ -26,6 +26,7 @@
 #include <algorithm>
 #include <cstdlib>
 #include <fstream>
+#include <sys/stat.h>
 #include <utility>
 
 #include <simplecpp.h>
@@ -266,6 +267,13 @@ bool Path::fileExists(const std::string &file)
     return f.is_open();
 }
 
+
+bool Path::directoryExists(const std::string &path)
+{
+    struct stat info;
+    return stat(path.c_str(), &info) == 0 && (info.st_mode & S_IFDIR);
+}
+
 std::string Path::join(std::string path1, std::string path2) {
     if (path1.empty() || path2.empty())
         return path1 + path2;

lib/path.h

@@ -187,6 +187,13 @@ public:
      */
     static bool fileExists(const std::string &file);
 
+    /**
+     * @brief Checks if a directory exists
+     * @param path Path to be checked
+     * @return true if given path is a directory
+     */
+    static bool directoryExists(const std::string &path);
+
     /**
      * join 2 paths with '/' separators
      */

test/testcmdlineparser.cpp

@@ -237,6 +237,10 @@ private:
         TEST_CASE(undefs_noarg3);
         TEST_CASE(undefs);
         TEST_CASE(undefs2);
+
+        TEST_CASE(cppcheckBuildDirExistent);
+        TEST_CASE(cppcheckBuildDirNonExistent);
+        TEST_CASE(cppcheckBuildDirEmpty);
     }
 
 
@@ -1947,6 +1951,27 @@ private:
         ASSERT_EQUALS(false, defParser.parseFromArgs(4, argv));
         ASSERT_EQUALS("cppcheck: error: argument to '-U' is missing.\n", GET_REDIRECT_OUTPUT);
     }
+
+    void cppcheckBuildDirExistent() {
+        REDIRECT;
+        const char * const argv[] = {"cppcheck", "--cppcheck-build-dir=."};
+        ASSERT_EQUALS(true, defParser.parseFromArgs(2, argv));
+        ASSERT_EQUALS("", GET_REDIRECT_OUTPUT);
+    }
+
+    void cppcheckBuildDirNonExistent() {
+        REDIRECT;
+        const char * const argv[] = {"cppcheck", "--cppcheck-build-dir=non-existent-path"};
+        ASSERT_EQUALS(false, defParser.parseFromArgs(2, argv));
+        ASSERT_EQUALS("cppcheck: error: Directory 'non-existent-path' specified by --cppcheck-build-dir argument has to be existent.\n", GET_REDIRECT_OUTPUT);
+    }
+
+    void cppcheckBuildDirEmpty() {
+        REDIRECT;
+        const char * const argv[] = {"cppcheck", "--cppcheck-build-dir="};
+        ASSERT_EQUALS(false, defParser.parseFromArgs(2, argv));
+        ASSERT_EQUALS("cppcheck: error: Directory '' specified by --cppcheck-build-dir argument has to be existent.\n", GET_REDIRECT_OUTPUT);
+    }
 };
 
 REGISTER_TEST(TestCmdlineParser)