difftool: make --gui, --tool and --extcmd mutually exclusive

diff --git a/submodule.c b/submodule.c
index 25c6e5d5b92e8501a2ad6ae93c5ca10b86d330a3..d9d3046689c0aa44458d0417cae8abd343535bbb 100644 (file)
--- a/submodule.c
+++ b/submodule.c
@@ -1886,7 +1886,7 @@ const char *get_superproject_working_tree(void)
                 * We're only interested in the name after the tab.
                 */
                super_sub = strchr(sb.buf, '\t') + 1;
-               super_sub_len = sb.buf + sb.len - super_sub - 1;
+               super_sub_len = strlen(super_sub);
 
                if (super_sub_len > cwd_len ||
                    strcmp(&cwd[cwd_len - super_sub_len], super_sub))