diff: ensure correct lifetime of external_diff_cmd

diff --git a/diff.c b/diff.c
index dc9965e836cd49c46a01293ef1d678a619b8f997..5634992bbc374442d68ee8b9fb3f881bd417b2b1 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -489,7 +489,7 @@ static const char *external_diff(void)
 
        if (done_preparing)
                return external_diff_cmd;
-       external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
+       external_diff_cmd = xstrdup_or_null(getenv("GIT_EXTERNAL_DIFF"));
        if (!external_diff_cmd)
                external_diff_cmd = external_diff_cmd_cfg;
        done_preparing = 1;