format-patch: add --creation-factor tweak for --range-diff

When generating a range-diff, matching up commits between two version of
a patch series involves heuristics, thus may give unexpected results.
git-range-diff allows tweaking the heuristic via --creation-factor.
Follow suit by accepting --creation-factor in combination with
--range-diff when generating a range-diff for a cover-letter.

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

diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt
index 425145f536f4a45d2fce146e4a384e2ec3eb6851..9b2e17215999cc56553ed3234e6084bc7cc8a580 100644 (file)
--- a/Documentation/git-format-patch.txt
+++ b/Documentation/git-format-patch.txt
@@ -24,7 +24,7 @@ SYNOPSIS
                   [--to=<email>] [--cc=<email>]
                   [--[no-]cover-letter] [--quiet] [--notes[=<ref>]]
                   [--interdiff=<previous>]
-                  [--range-diff=<previous>]
+                  [--range-diff=<previous> [--creation-factor=<percent>]]
                   [--progress]
                   [<common diff options>]
                   [ <since> | <revision range> ]
@@ -250,6 +250,12 @@ feeding the result to `git send-email`.
        disjoint (for example `git format-patch --cover-letter
        --range-diff=feature/v1~3..feature/v1 -3 feature/v2`).
 
+--creation-factor=<percent>::
+       Used with `--range-diff`, tweak the heuristic which matches up commits
+       between the previous and current series of patches by adjusting the
+       creation/deletion cost fudge factor. See linkgit:git-range-diff[1])
+       for details.
+
 --notes[=<ref>]::
        Append the notes (see linkgit:git-notes[1]) for the commit
        after the three-dash line.

diff --git a/builtin/log.c b/builtin/log.c
index 0dc17fe32519570afbd2d9c2ed6b12c4b1c25e36..05965a57ca6ea43a3de19283d278051120d75697 100644 (file)
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -1498,6 +1498,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
        struct strbuf rdiff1 = STRBUF_INIT;
        struct strbuf rdiff2 = STRBUF_INIT;
        struct strbuf rdiff_title = STRBUF_INIT;
+       int creation_factor = -1;
 
        const struct option builtin_format_patch_options[] = {
                { OPTION_CALLBACK, 'n', "numbered", &numbered, NULL,
@@ -1576,6 +1577,8 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
                             parse_opt_object_name),
                OPT_STRING(0, "range-diff", &rdiff_prev, N_("refspec"),
                           N_("show changes against <refspec> in cover letter")),
+               OPT_INTEGER(0, "creation-factor", &creation_factor,
+                           N_("percentage by which creation is weighted")),
                OPT_END()
        };
 
@@ -1808,6 +1811,11 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
                                             _("Interdiff against v%d:"));
        }
 
+       if (creation_factor < 0)
+               creation_factor = RANGE_DIFF_CREATION_FACTOR_DEFAULT;
+       else if (!rdiff_prev)
+               die(_("--creation-factor requires --range-diff"));
+
        if (rdiff_prev) {
                if (!cover_letter)
                        die(_("--range-diff requires --cover-letter"));
@@ -1816,7 +1824,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
                                        origin, list[0]);
                rev.rdiff1 = rdiff1.buf;
                rev.rdiff2 = rdiff2.buf;
-               rev.creation_factor = RANGE_DIFF_CREATION_FACTOR_DEFAULT;
+               rev.creation_factor = creation_factor;
                rev.rdiff_title = diff_title(&rdiff_title, reroll_count,
                                             _("Range-diff:"),
                                             _("Range-diff against v%d:"));