[PATCH v4] rerere: fix overeager gc
- From
SZEDER Gábor <szeder@ira.uka.de>
- Date
- Jul 8, 2010, 14:35 UTC
- Message-ID
- <1278599758-18962-1-git-send-email-szeder@ira.uka.de>
- In-Reply-To
- <4C31757A.1000207@viscovery.net>
'rerere gc' prunes resolutions of conflicted merges that occurred long time ago, and when doing so it takes the creation time of the conflicted automerge results into account. This can cause the loss of frequently used merge resolutions (e.g. long-living topic branches are merged into a regularly rebuilt integration branch (think of git's pu)) when they become old enough to exceed 'rerere gc's threshold.
To prevent the loss of valuable merge resolutions 'rerere' will (1) write 'thisimage' into a temporary file and then rename it into its final destination, thereby updating the directory timestamp each time when encountering the same merge conflict, and (2) take the directory timestamp, i.e. the time of the last usage into account when gc'ing.
Signed-off-by: SZEDER Gábor <szeder@ira.uka.de> ---
On Mon, Jul 05, 2010 at 08:02:34AM +0200, Johannes Sixt wrote:
Show 7 quoted lines
> Am 7/2/2010 19:25, schrieb Junio C Hamano: > > If we for whatever reason trust placing an extra timestamp on a regular > > file more than using directory timestamp (which I think may be a valid > > concern from portability point of view), > > Windows behaves well in this regard. Writing of thisimage must be > converted to lockfile infrastructure, of course.
So, here is the next take with the tmpfile-rename stuff to update the directory timestamp. If there are any portability issues wrt directory timestamp updating, the new test should catch them early.
builtin/rerere.c | 6 +++--- rerere.c | 19 +++++++++++++++++-- t/t4200-rerere.sh | 16 ++++++++++++---- 3 files changed, 32 insertions(+), 9 deletions(-)
diff --git a/builtin/rerere.c b/builtin/rerere.c index 980d542..bede3eb 100644 --- a/builtin/rerere.c +++ b/builtin/rerere.c @@ -13,10 +13,10 @@ static const char git_rerere_usage[] = static int cutoff_noresolve = 15; static int cutoff_resolve = 60; -static time_t rerere_created_at(const char *name) +static time_t rerere_last_used_at(const char *name) { struct stat st; - return stat(rerere_path(name, "preimage"), &st) ? (time_t) 0 : st.st_mtime; + return stat(rerere_path(name, "."), &st) ? (time_t) 0 : st.st_mtime; } static void unlink_rr_item(const char *name) @@ -53,7 +53,7 @@ static void garbage_collect(struct string_list *rr) while ((e = readdir(dir))) { if (is_dot_or_dotdot(e->d_name)) continue; - then = rerere_created_at(e->d_name); + then = rerere_last_used_at(e->d_name); if (!then) continue; cutoff = (has_rerere_resolution(e->d_name) diff --git a/rerere.c b/rerere.c index d03a696..e415f54 100644 --- a/rerere.c +++ b/rerere.c @@ -363,13 +363,28 @@ static int find_conflict(struct string_list *conflict) static int merge(const char *name, const char *path) { - int ret; + int fd, ret; mmfile_t cur = {NULL, 0}, base = {NULL, 0}, other = {NULL, 0}; mmbuffer_t result = {NULL, 0}; + char *tmpfile; + + tmpfile = xstrdup(rerere_path(name, "tmp_thisimage_XXXXXX")); + fd = git_mkstemp_mode(tmpfile, 0600); + if (fd < 0) { + error("unable to create temporary file %s for rerere: %s\n", + tmpfile, strerror(errno)); + return 1; + } + close(fd); - if (handle_file(path, NULL, rerere_path(name, "thisimage")) < 0) + if (handle_file(path, NULL, tmpfile) < 0) return 1; + if (move_temp_to_file(tmpfile, rerere_path(name, "thisimage")) < 0) + return 1; + + free(tmpfile); + if (read_mmfile(&cur, rerere_path(name, "thisimage")) || read_mmfile(&base, rerere_path(name, "preimage")) || read_mmfile(&other, rerere_path(name, "postimage"))) { diff --git a/t/t4200-rerere.sh b/t/t4200-rerere.sh index 70856d0..a425329 100755 --- a/t/t4200-rerere.sh +++ b/t/t4200-rerere.sh @@ -144,6 +144,14 @@ test_expect_success 'rerere kicked in' "! grep ^=======$ a1" test_expect_success 'rerere prefers first change' 'test_cmp a1 expect' +test_expect_success 'rerere updates directory timestamp' ' + git reset --hard && + oldmtime=$(test-chmtime -v -42 $rr |cut -f 1) && + test_must_fail git pull . first && + newmtime=$(test-chmtime -v +0 $rr |cut -f 1) && + test $oldmtime -lt $newmtime +' + rm $rr/postimage echo "$sha1 a1" | perl -pe 'y/\012/\000/' > .git/MERGE_RR @@ -165,16 +173,16 @@ just_over_15_days_ago=$((-1-15*86400)) almost_60_days_ago=$((60-60*86400)) just_over_60_days_ago=$((-1-60*86400)) -test-chmtime =$almost_60_days_ago $rr/preimage -test-chmtime =$almost_15_days_ago $rr2/preimage +test-chmtime =$almost_60_days_ago $rr +test-chmtime =$almost_15_days_ago $rr2 test_expect_success 'garbage collection (part1)' 'git rerere gc' test_expect_success 'young records still live' \ "test -f $rr/preimage && test -f $rr2/preimage" -test-chmtime =$just_over_60_days_ago $rr/preimage -test-chmtime =$just_over_15_days_ago $rr2/preimage +test-chmtime =$just_over_60_days_ago $rr +test-chmtime =$just_over_15_days_ago $rr2 test_expect_success 'garbage collection (part2)' 'git rerere gc'
-- 1.7.2.rc2.42.gfe876