compat: make p_realpath Windows implementation be a bit more POSIX compliant and…

compat: make p_realpath Windows implementation be a bit more POSIX compliant and fail if the provided path does not lead to an existing entry

src/path.c

@@ -205,9 +205,13 @@ int git_path_prettify(git_buf *path_out, const char *path, const char *base)
 	}
 
 	if (p_realpath(path, buf) == NULL) {
+		/* giterr_set resets the errno when dealing with a GITERR_OS kind of error */
+		int error = (errno == ENOENT || errno == ENOTDIR) ? GIT_ENOTFOUND : -1;
 		giterr_set(GITERR_OS, "Failed to resolve path '%s'", path);
+
 		git_buf_clear(path_out);
-		return (errno == ENOENT || errno == ENOTDIR) ? GIT_ENOTFOUND : -1;
+		
+		return error;
 	}
 
 	return git_buf_sets(path_out, buf);

src/win32/posix_w32.c

@@ -326,7 +326,7 @@ int p_hide_directory__w32(const char *path)
 
 char *p_realpath(const char *orig_path, char *buffer)
 {
-	int ret;
+	int ret, buffer_sz = 0;
 	wchar_t* orig_path_w = gitwin_to_utf16(orig_path);
 	wchar_t* buffer_w = (wchar_t*)git__malloc(GIT_PATH_MAX * sizeof(wchar_t));
 
@@ -336,13 +336,14 @@ char *p_realpath(const char *orig_path, char *buffer)
 	ret = GetFullPathNameW(orig_path_w, GIT_PATH_MAX, buffer_w, NULL);
 	git__free(orig_path_w);
 
-	if (!ret || ret > GIT_PATH_MAX) {
+	/* According to MSDN, a return value equals to zero means a failure. */
+	if (ret == 0 || ret > GIT_PATH_MAX) {
 		buffer = NULL;
 		goto done;
 	}
 
 	if (buffer == NULL) {
-		int buffer_sz = WideCharToMultiByte(CP_UTF8, 0, buffer_w, -1, NULL, 0, NULL, NULL);
+		buffer_sz = WideCharToMultiByte(CP_UTF8, 0, buffer_w, -1, NULL, 0, NULL, NULL);
 
 		if (!buffer_sz ||
 			!(buffer = (char *)git__malloc(buffer_sz)) ||
@@ -350,10 +351,22 @@ char *p_realpath(const char *orig_path, char *buffer)
 		{
 			git__free(buffer);
 			buffer = NULL;
+			goto done;
 		}
 	} else {
-		if (!WideCharToMultiByte(CP_UTF8, 0, buffer_w, -1, buffer, GIT_PATH_MAX, NULL, NULL))
+		if (!WideCharToMultiByte(CP_UTF8, 0, buffer_w, -1, buffer, GIT_PATH_MAX, NULL, NULL)) {
+			buffer = NULL;
+			goto done;
+		}
+	}
+
+	if (!git_path_exists(buffer))
+	{
+		if (buffer_sz > 0)
+			git__free(buffer);
+
 		buffer = NULL;
+		errno = ENOENT;
 	}
 
 done:

tests-clar/core/path.c

@@ -405,3 +405,16 @@ void test_core_path__12_offset_to_path_root(void)
 	cl_assert(git_path_root("//computername") == -1);
 #endif
 }
+
+#define NON_EXISTING_FILEPATH "i_hope_i_do_not_exist"
+
+void test_core_path__13_cannot_prettify_a_non_existing_file(void)
+{
+	git_buf p = GIT_BUF_INIT;
+
+	cl_must_pass(git_path_exists(NON_EXISTING_FILEPATH) == false);
+	cl_assert_equal_i(GIT_ENOTFOUND, git_path_prettify(&p, NON_EXISTING_FILEPATH, NULL));
+	cl_assert_equal_i(GIT_ENOTFOUND, git_path_prettify(&p, NON_EXISTING_FILEPATH "/so-do-i", NULL));
+
+	git_buf_free(&p);
+}