format-patch: use 'origin' as start of current-series-range when known

When formatting a patch series over `origin..HEAD`, one would expect
that range to be used as the current-series-range when computing a
range-diff between the previous and current versions of a patch series.
However, infer_range_diff_ranges() ignores `origin..HEAD` when
--range-diff=<prev> specifies a single revision rather than a range, and
instead unexpectedly computes the current-series-range based upon
<prev>. Address this anomaly by unconditionally using `origin..HEAD` as
the current-series-range regardless of <prev> as long as `origin` is
known, and only fall back to basing current-series-range on <prev> when
`origin` is not known.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/log.c b/builtin/log.c
index 37177b3e7fc1eadb7fd2dd0e59595d85f1b72af9..f79b2b87758a6fc6748e10a7cf670b42496948ef 100644 (file)
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -1595,16 +1595,20 @@ static void infer_range_diff_ranges(struct strbuf *r1,
                                    struct commit *head)
 {
        const char *head_oid = oid_to_hex(&head->object.oid);
+       int prev_is_range = !!strstr(prev, "..");
 
-       if (!strstr(prev, "..")) {
+       if (prev_is_range)
+               strbuf_addstr(r1, prev);
+       else
                strbuf_addf(r1, "%s..%s", head_oid, prev);
+
+       if (origin)
+               strbuf_addf(r2, "%s..%s", oid_to_hex(&origin->object.oid), head_oid);
+       else if (prev_is_range)
+               die(_("failed to infer range-diff origin of current series"));
+       else {
+               warning(_("using '%s' as range-diff origin of current series"), prev);
                strbuf_addf(r2, "%s..%s", prev, head_oid);
-       } else if (!origin) {
-               die(_("failed to infer range-diff ranges"));
-       } else {
-               strbuf_addstr(r1, prev);
-               strbuf_addf(r2, "%s..%s",
-                           oid_to_hex(&origin->object.oid), head_oid);
        }
 }