[PATCH 6/7] diff: handle sha1 abbreviations outside of repository
- From
Jeff King <peff@peff.net>
- Date
- Oct 20, 2016, 06:21 UTC
- Message-ID
- <20161020062125.3iqej3bpdoitr3fz@sigill.intra.peff.net>
- In-Reply-To
- <20161020061536.6fqh23xb2nhxodpa@sigill.intra.peff.net>
When generating diffs outside a repository (e.g., with "diff --no-index"), we may write abbreviated sha1s as part of "--raw" output or the "index" lines of "--patch" output. Since we have no object database, we never find any collisions, and these sha1s get whatever static abbreviation length is configured (typically 7).
However, we do blindly look in ".git/objects" to see if any objects exist, even though we know we are not in a repository. This is usually harmless because such a directory is unlikely to exist, but could be wrong in rare circumstances.
Let's instead notice when we are not in a repository and behave as if the object database is empty (i.e., just use the default abbrev length). It would perhaps make sense to be conservative and show full sha1s in that case, but showing the default abbreviation is what we've always done (and is certainly less ugly).
Note that this does mean that:
cd /not/a/repo GIT_OBJECT_DIRECTORY=/some/real/objdir git diff --no-index ...
used to look for collisions in /some/real/objdir but now does not. This could be considered either a bugfix (we do not look at objects if we have no repository) or a regression, but it seems unlikely that anybody would care much either way.
Signed-off-by: Jeff King <peff@peff.net> --- diff.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/diff.c b/diff.c index 8f0f309..ef11001 100644 --- a/diff.c +++ b/diff.c @@ -3049,6 +3049,19 @@ static int similarity_index(struct diff_filepair *p) return p->score * 100 / MAX_SCORE; } +static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev) +{ + if (startup_info->have_repository) + return find_unique_abbrev(oid->hash, abbrev); + else { + char *hex = oid_to_hex(oid); + if (abbrev < 0 || abbrev > GIT_SHA1_HEXSZ) + die("BUG: oid abbreviation out of range: %d", abbrev); + hex[abbrev] = '\0'; + return hex; + } +} + static void fill_metainfo(struct strbuf *msg, const char *name, const char *other, @@ -3107,9 +3120,9 @@ static void fill_metainfo(struct strbuf *msg, (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two))) abbrev = 40; } - strbuf_addf(msg, "%s%sindex %s..", line_prefix, set, - find_unique_abbrev(one->oid.hash, abbrev)); - strbuf_add_unique_abbrev(msg, two->oid.hash, abbrev); + strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set, + diff_abbrev_oid(&one->oid, abbrev), + diff_abbrev_oid(&two->oid, abbrev)); if (one->mode == two->mode) strbuf_addf(msg, " %06o", one->mode); strbuf_addf(msg, "%s\n", reset); @@ -4144,7 +4157,7 @@ const char *diff_aligned_abbrev(const struct object_id *oid, int len) if (len == GIT_SHA1_HEXSZ) return oid_to_hex(oid); - abbrev = find_unique_abbrev(oid->hash, len); + abbrev = diff_abbrev_oid(oid, len); abblen = strlen(abbrev); /*
-- 2.10.1.619.g16351a7