git_extract_argv0_path(): Move check for valid argv0 from caller to c…

…allee

This simplifies the calling code.

Signed-off-by: Steffen Prohaska <prohaska@zib.de>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

exec_cmd.c

@@ -22,7 +22,11 @@ const char *system_path(const char *path)
 
 const char *git_extract_argv0_path(const char *argv0)
 {
-	const char *slash = argv0 + strlen(argv0);
+	const char *slash;
+
+	if (!argv0 || !*argv0)
+		return NULL;
+	slash = argv0 + strlen(argv0);
 
 	while (argv0 <= slash && !is_dir_sep(*slash))
 		slash--;

git.c

@@ -444,9 +444,8 @@ int main(int argc, const char **argv)
 {
 	const char *cmd;
 
-	if (argv[0] && *argv[0])
-		cmd = git_extract_argv0_path(argv[0]);
-	else
+	cmd = git_extract_argv0_path(argv[0]);
+	if (!cmd)
 		cmd = "git-help";
 
 	/*