do_one_ref(): null_sha1 check is not about broken ref

diff --git a/combine-diff.c b/combine-diff.c
index b82f46cc60733aded42ebd95c0163c16d7aaaa1c..1a6f9d1df5b7dcafbdaa2d64c45554e129972be2 100644 (file)
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -164,20 +164,22 @@ static void consume_line(void *state_, char *line, unsigned long len)
                                      &state->nb, &state->nn))
                        return;
                state->lno = state->nb;
-               if (!state->nb)
-                       /* @@ -1,2 +0,0 @@ to remove the
-                        * first two lines...
-                        */
-                       state->nb = 1;
-               if (state->nn == 0)
+               if (state->nn == 0) {
                        /* @@ -X,Y +N,0 @@ removed Y lines
                         * that would have come *after* line N
                         * in the result.  Our lost buckets hang
                         * to the line after the removed lines,
+                        *
+                        * Note that this is correct even when N == 0,
+                        * in which case the hunk removes the first
+                        * line in the file.
                         */
                        state->lost_bucket = &state->sline[state->nb];
-               else
+                       if (!state->nb)
+                               state->nb = 1;
+               } else {
                        state->lost_bucket = &state->sline[state->nb-1];
+               }
                if (!state->sline[state->nb-1].p_lno)
                        state->sline[state->nb-1].p_lno =
                                xcalloc(state->num_parent,