Make diffcore_std only can run once before a diff_flush

When file renames/copies detection is turned on, the
second diffcore_std will degrade a 'C' pair to a 'R' pair.

And this may happen when we run 'git log --follow' with
hard copies finding. That is, the try_to_follow_renames()
will run diffcore_std to find the copies, and then
'git log' will issue another diffcore_std, which will reduce
'src->rename_used' and recognize this copy as a rename.
This is not what we want.

So, I think we really don't need to run diffcore_std more
than one time.

Signed-off-by: Bo Yang <struggleyb.nku@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/diff.c b/diff.c
index 4a350e365e5f4d0c61977546e620bf6b79679dd5..f0985bc76a84d7adc7dcc6b294a7a6e9cf90bf6b 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -3737,6 +3737,12 @@ void diffcore_fix_diff_index(struct diff_options *options)
 
 void diffcore_std(struct diff_options *options)
 {
+       /* We never run this function more than one time, because the
+        * rename/copy detection logic can only run once.
+        */
+       if (diff_queued_diff.run)
+               return;
+
        if (options->skip_stat_unmatch)
                diffcore_skip_stat_unmatch(options);
        if (options->break_opt != -1)
@@ -3756,6 +3762,8 @@ void diffcore_std(struct diff_options *options)
                DIFF_OPT_SET(options, HAS_CHANGES);
        else
                DIFF_OPT_CLR(options, HAS_CHANGES);
+
+       diff_queued_diff.run = 1;
 }
 
 int diff_result_code(struct diff_options *opt, int status)

diff --git a/diffcore.h b/diffcore.h
index 5d05deaf68b7c44a98456e9c0e12a7af2230f116..491bea0b44963461cfce30b07ec96a9005a3c910 100644 (file)
--- a/diffcore.h
+++ b/diffcore.h
@@ -91,11 +91,13 @@ struct diff_queue_struct {
        struct diff_filepair **queue;
        int alloc;
        int nr;
+       int run;
 };
 #define DIFF_QUEUE_CLEAR(q) \
        do { \
                (q)->queue = NULL; \
                (q)->nr = (q)->alloc = 0; \
+               (q)->run = 0; \
        } while(0);
 
 extern struct diff_queue_struct diff_queued_diff;