submodule: fix segmentation fault in submodule--helper clone

diff --git a/convert.c b/convert.c
index 4bb4ec1d836e695a86f309b276fd07e300885c57..8cd6222a263ac99a63335bf7080a3fb4dd797ff7 100644 (file)
--- a/convert.c
+++ b/convert.c
@@ -434,7 +434,7 @@ static int apply_filter(const char *path, const char *src, size_t len, int fd,
        struct async async;
        struct filter_params params;
 
-       if (!cmd)
+       if (!cmd || !*cmd)
                return 0;
 
        if (!dst)