pickaxe: hoist empty needle check

If we are given an empty pickaxe needle like "git log -S ''",
it is impossible for us to find anything (because no matter
what the content, the count will always be 0). We currently
check this at the lowest level of contains(). Let's hoist
the logic much earlier to has_changes(), so that it is
simpler to return our answer before loading any blob data.

Signed-off-by: Jeff King <peff@peff.net>

diff --git a/diffcore-pickaxe.c b/diffcore-pickaxe.c
index a20937635435f6672f801454c992cbeeb8d17a1a..61f628c28579a0350065ae0b7725624625e03ba5 100644 (file)
--- a/diffcore-pickaxe.c
+++ b/diffcore-pickaxe.c
@@ -163,8 +163,6 @@ static unsigned int contains(struct diff_filespec *one, struct diff_options *o,
        unsigned int cnt;
        unsigned long sz;
        const char *data;
-       if (!o->pickaxe[0])
-               return 0;
        if (diff_populate_filespec(one, 0))
                return 0;
 
@@ -206,6 +204,9 @@ static unsigned int contains(struct diff_filespec *one, struct diff_options *o,
 static int has_changes(struct diff_filepair *p, struct diff_options *o,
                       regex_t *regexp, kwset_t kws)
 {
+       if (!o->pickaxe[0])
+               return 0;
+
        if (!DIFF_FILE_VALID(p->one)) {
                if (!DIFF_FILE_VALID(p->two))
                        return 0; /* ignore unmerged */