git-p4: Unset P4DIFF environment variable when using 'p4 -du diff'

diff --git a/archive-tar.c b/archive-tar.c
index e1bced56093dc08bbc260736637af3356b8598bb..30aa2e23fdbb1630dffb27db4509bc529bbd884a 100644 (file)
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -222,7 +222,7 @@ static void write_global_extended_header(const unsigned char *sha1)
 static int git_tar_config(const char *var, const char *value)
 {
        if (!strcmp(var, "tar.umask")) {
-               if (!strcmp(value, "user")) {
+               if (value && !strcmp(value, "user")) {
                        tar_umask = umask(0);
                        umask(tar_umask);
                } else {