[PATCH 1/3] patch-ids: turn off rename detection
- From
Jeff King <peff@peff.net>
- Date
- Sep 7, 2016, 22:02 UTC
- Message-ID
- <20160907220232.uotocvgdojfcl4o4@sigill.intra.peff.net>
- In-Reply-To
- <20160907220101.hwwutkiagfottbdd@sigill.intra.peff.net>
The patch-id code may be running inside another porcelain like "git log" or "git format-patch", and therefore may have set diff_detect_rename_default, either via the diff-ui config, or by default since 5404c11 (diff: activate diff.renames by default, 2016-02-25). This is the case even if a command is run with `--no-renames`, as that is applied only to the diff-options used by the command itself.
Rename detection doesn't help the patch-id results. It _may_ actually hurt, as minor differences in the files that would be overlooked by patch-id's canonicalization might result in different renames (though I'd doubt that it ever comes up in practice).
But mostly it is just a waste of CPU to compute these renames.
Note that this does have one user-visible impact: the prerequisite patches listed by "format-patch --base". There may be some confusion between different versions of git as older ones will enable renames, but newer ones will not. However, this was already a problem, as people with different settings for the "diff.renames" config would get different results. After this patch, everyone should get the same results, regardless of their config.
Signed-off-by: Jeff King <peff@peff.net> --- The patch is the same as v1, but the commit message is modified, as I realized that "--base" does expose this value publicly (but as I argue above, this is probably an improvement).
patch-ids.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/patch-ids.c b/patch-ids.c index 082412a..77e4663 100644 --- a/patch-ids.c +++ b/patch-ids.c @@ -45,6 +45,7 @@ int init_patch_ids(struct patch_ids *ids) { memset(ids, 0, sizeof(*ids)); diff_setup(&ids->diffopts); + ids->diffopts.detect_rename = 0; DIFF_OPT_SET(&ids->diffopts, RECURSIVE); diff_setup_done(&ids->diffopts); hashmap_init(&ids->patches, (hashmap_cmp_fn)patch_id_cmp, 256);
-- 2.10.0.rc2.154.gb4a4b8b