When we are limiting a rev-list traversal due to
UNINTERESTING refs, we have to walk down the tips (both
interesting and uninteresting) to find where they intersect.
We keep a queue of commits to examine, pop commits off
the queue one by one, and potentially add their parents. The
size of the queue will naturally fluctuate based on the
"width" of the history graph; i.e., the number of
simultaneous lines of development. But for the most part it
will stay in the same ballpark as the initial number of tips
we fed, shrinking over time (as we hit common ancestors of
the tips). So roughly speaking, if we start with `N` tips,
we'll spend much of the time with a queue around `N` items.
For each UNINTERESTING commit we pop, we call
still_interesting to check whether marking its parents as
UNINTERESTING has made the whole queue uninteresting (in
which case we can quit early). Because the queue is stored
as a linked list, this is `O(N)`, where `N` is the number of
items in the queue. So processing a queue with `N` commits
marked UNINTERESTING (and one or more interesting commits)
will take `O(N^2)`.
If you feed a lot of positive tips, this isn't a problem.
They aren't UNINTERESTING, so they don't incur the
still_interesting check. It also isn't a problem if you
traverse from an interesting tip to some UNINTERESTING
bases. We order the queue by recency, so the interesting
commits stay at the front of the queue as we walk down them.
The linear check can exit early as soon as it sees one
interesting commit left in the queue.
But if you want to know whether an older commit is reachable
from a set of newer tips, we end up processing in the
opposite direction: from the UNINTERESTING ones down to the
interesting one. This may happen when we call:
git rev-list $commits --not --all
in check_everything_connected after a fetch. If we fetched
something much older than most of our refs, and if we have a
large number of refs, the traversal cost is dominated by the
quadratic behavior.
These commands simulate the connectivity check of such a
fetch, when you have `$n` distinct refs in the receiver:
# positive ref is 100,000 commits deep
git rev-list --all | head -100000 | tail -1 >input
# huge number of more recent negative refs
git rev-list --all | head -$n | sed s/^/^/ >>input
time git rev-list --stdin <input
Here are timings for various `n` on the linux.git
repository. The `n=1` case provides a baseline for just
walking the commits, which lets us see the still_interesting
overhead. The times marked with `+` subtract that baseline
to show just the extra time growth due to the large number
of refs. The `x` numbers show the slowdown of the adjusted
time versus the prior trial.
n | before | after
--------------------------------------------------------
1 | 0.991s | 0.848s
10000 | 1.120s (+0.129s) | 0.885s (+0.037s)
20000 | 1.451s (+0.460s, 3.5x) | 0.923s (+0.075s, 2.0x)
40000 | 2.731s (+1.740s, 3.8x) | 0.994s (+0.146s, 1.9x)
80000 | 8.235s (+7.244s, 4.2x) | 1.123s (+0.275s, 1.9x)
Each trial doubles `n`, so you can see the quadratic (`4x`)
behavior before this patch. Afterwards, we have a roughly
linear relationship.
The implementation is fairly straightforward. Whenever we do
the linear search, we cache the interesting commit we find,
and next time check it before doing another linear search.
If that commit is removed from the list or becomes
UNINTERESTING itself, then we fall back to the linear
search. This is very similar to the trick used by fce87ae
(Fix quadratic performance in rewrite_one., 2008-07-12).
I considered and rejected several possible alternatives:
1. Keep a count of UNINTERESTING commits in the queue.
This requires managing the count not only when removing
an item from the queue, but also when marking an item
as UNINTERESTING. That requires touching the other
functions which mark commits, and would require knowing
quickly which commits are in the queue (lookup in the
queue is linear, so we would need an auxiliary
structure or to also maintain an IN_QUEUE flag in each
commit object).
2. Keep a separate list of interesting commits. Drop items
from it when they are dropped from the queue, or if
they become UNINTERESTING. This again suffers from
extra complexity to maintain the list, not to mention
CPU and memory.
3. Use a better data structure for the queue. This is
something that could help the fix in fce87ae, because
we order the queue by recency, and it is about
inserting quickly in recency order. So a normal
priority queue would help there. But here, we cannot
disturb the order of the queue, which makes things
harder. We really do need an auxiliary index to track
the flag we care about, which is basically option (2)
above.
The "cache" trick is simple, and the numbers above show that
it works well in practice. This is because the length of
time it takes to find an interesting commit is proportional
to the length of time it will remain cached (i.e., if we
have to walk a long way to find it, it also means we have to
pop a lot of elements in the queue until we get rid of it
and have to find another interesting commit).
The worst case is still quadratic, though. We could have `N`
uninteresting commits at the front of the queue, followed by
`N` interesting commits, where commit `i` has parent `i+N`.
When we pop commit `i`, we will notice that the parent of
the next commit, `i+1+N` is still interesting and cache it.
But then handling commit `i+1`, we will mark its parent
`i+1+N` uninteresting, and immediately invalidate our cache.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When commit fe8e3b7 refactored type_from_string to allow
input that was not NUL-terminated, it switched to using
strncmp instead of strcmp. But this means we check only the
first "len" bytes of the strings, and ignore any remaining
bytes in the object_type_string. We should make sure that it
is also "len" bytes, or else we would accept "comm" as
"commit", and so forth.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The name (not user) and email setting should be in config section
"user" and not in "core" as documented in Documentation/config.txt.
Signed-off-by: Ossi Herrala <oherrala@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The second argument to test_path_is_file and test_path_is_dir
must be $2 and not $*, which instead would repeat the file
name in the error message.
Signed-off-by: Elia Pinto <gitter.spiros@gmail.com>
Reviewed-by: Matthieu Moy <Matthieu.Moy@grenoble-inp.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Because the function reads one character at the time, unfortunately
we cannot use the easier skip_utf8_bom() helper, but at least we do
not have to duplicate the constant string this way.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
With the recent change to ignore the UTF8 BOM at the beginning of
.gitignore files, we now have two codepaths that do such a skipping
(the other one is for reading the configuration files).
Introduce utf8_bom[] constant string and skip_utf8_bom() helper
and teach .gitignore code how to use it.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Even though the previous step shifts where the "entry" begins, we
still iterate over the original buf[], which may begin with the
UTF-8 BOM we are supposed to be skipping. At the end of the first
line, the code grabs the contents of it starting at "entry", so
there is nothing wrong per-se, but the logic looks really confused.
Instead, move the buf pointer and shrink its size, to truly
pretend that UTF-8 BOM did not exist in the input.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Some text editors like Notepad or LibreOffice write an UTF-8 BOM in
order to indicate that the file is Unicode text rather than whatever the
current locale would indicate.
If someone uses such an editor to edit a gitignore file, we are left
with those three bytes at the beginning of the file. If we do not skip
them, we will attempt to match a filename with the BOM as prefix, which
won't match the files the user is expecting.
Signed-off-by: Carlos Martín Nieto <cmn@elego.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This reverts commit 2bf15a3330, whose
intention was good, but the verbosity levels used in merge-recursive
turns out to be rather uneven. For example, a merge of two branches
with conflicting submodule updates used to report CONFLICT: output
with --quiet but no longer (which *is* desired), while the final
"Automatic merge failed; fix conflicts and then commit" message is
still shown even with --quiet (which *is* inconsistent).
Originally reported by Bryan Turner; it is too early to declare what
the concensus is, but it seems that we would need to level the
verbosity levels used in merge strategy backends before we can go
forward. In the meantime, we'd revert to the old behaviour until
that happens.
cf. $gmane/267245
The function parses the input to compute the broken-down time in
"struct tm", and the GMT timezone offset. If the timezone offset
does not exist in the input, the broken-down time is turned into the
number of seconds since epoch both in the current timezone and in
GMT and the offset is computed as their difference.
However, we forgot to make sure tm.tm_isdst is set to -1 (i.e. let
the system figure out if DST is in effect in the current timezone
when turning the broken-down time to the number of seconds since
epoch); it is done so at the beginning of the function, but a call
to match_digit() in the function can lead to a call to gmtime_r() to
clobber the field.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Diagnosed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When the input does not have GMT timezone offset, the code computes
it by computing the local and GMT time for the given timestamp. But
there is no point doing so if the given timestamp is known to be a
bogus one.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"diff-highlight" (in contrib/) used to show byte-by-byte
differences, which meant that multi-byte characters can be chopped
in the middle. It learned to pay attention to character boundaries
(assuming the UTF-8 payload).
* jk/colors:
diff-highlight: do not split multibyte characters
"git merge --quiet" did not squelch messages from the underlying
merge-recursive strategy.
* jk/merge-quiet:
merge: pass verbosity flag down to merge-recursive
A push into an unborn branch, with "receive.denyCurrentBranch" set
to "updateInstead", did not check out the working tree as expected.
* jc/update-instead-into-void:
push-to-deploy: allow pushing into an unborn branch and updating it
Changed inaccurate count of "rough rules" from three to the more
generic 'a few'.
Signed-off-by: Julian Gindi <juliangindi@gmail.com>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The "help-all" option is being initialized with a wrong value.
While being semantically wrong this can also cause a segmentation
fault in gcc on ARMv7 hardfloat platforms with a hardened
toolchain. Fix this by initializing with a NULL value.
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Reviewed-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
By using a tree with multiple identical files and allowing copy detection to
choose any one of them, the check in the test is unnecessarily complex. We can
simplify by:
* Modify source file (file2) before copying the file.
* Check that only file2 is the source in the output of "p4 filelog".
* Remove all "case" statements and replace them with simple tests to check
that source is "file2".
Signed-off-by: Vitor Antunes <vitor.hda@gmail.com>
Acked-by: Luke Diamand <luke@diamand.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Ignore an extra ':' at the end of the hostname in URL's like
"ssh://example.com:/path/to/repo"
The colon is meant to separate a port number from the hostname.
If the port is empty, the colon should be ignored, see RFC 3986.
It had been working for URLs with ssh:// scheme, but was unintentionally
broken in 86ceb3, "allow ssh://user@[2001:db8::1]/repo.git"
Reported-by: Reid Woodbury Jr. <reidw@rawsound.com>
Signed-off-by: Torsten Bögershausen <tboegi@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Translate one message came from git.pot update in 6eebb35
(l10n: git.pot: v2.4.0 round 2 (1 update)).
Signed-off-by: Ralf Thielow <ralf.thielow@gmail.com>
When the input is UTF-8 and Perl is operating on bytes instead of
characters, a diff that changes one multibyte character to another
that shares an initial byte sequence will result in a broken diff
display as the common byte sequence prefix will be separated from
the rest of the bytes in the multibyte character.
For example, if a single line contains only the unicode character
U+C9C4 (encoded as UTF-8 0xEC, 0xA7, 0x84) and that line is then
changed to the unicode character U+C9C0 (encoded as UTF-8 0xEC,
0xA7, 0x80), when operating on bytes diff-highlight will show only
the single byte change from 0x84 to 0x80 thus creating invalid UTF-8
and a broken diff display.
Fix this by putting Perl into character mode when splitting the line
and then back into byte mode after the split is finished.
The utf8::xxx functions require Perl 5.8 so we require that as well.
Also, since we are mucking with code in the split_line function, we
change a '*' quantifier to a '+' quantifier when matching the $COLOR
expression which has the side effect of speeding everything up while
eliminating useless '' elements in the returned array.
Reported-by: Yi EungJun <semtlenori@gmail.com>
Signed-off-by: Kyle J. McKay <mackyle@gmail.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This makes "git merge --quiet" really quiet when we call
into merge-recursive.
Note that we can't just pass our flag down as-is; the two
parts of the code use different scales. We center at "0" as
normal for git-merge (with "--quiet" giving a negative
value), but merge-recursive uses "2" as its center. This
patch passes a negative value to merge-recursive rather than
"1", though, as otherwise the user would have to use "-qqq"
to squelch all messages (but the downside is that the user
cannot distinguish between levels 0-2 if without resorting
to the GIT_MERGE_VERBOSITY variable).
We may want to review and renormalize the message severities
in merge-recursive, but that does not have to happen now.
This is at least in improvement in the sense that we are
respecting "--quiet" at all.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
