When fetching with the v0 protocol over ssh (or a local upload-pack with
pipes), the server closes the connection as soon as it is finished
sending the pack. So even though the client may still be operating on
the data via index-pack (e.g., resolving deltas, checking connectivity,
etc), the server has released all resources.
With the v2 protocol, however, the server considers the ssh session only
as a transport, with individual requests coming over it. After sending
the pack, it goes back to its main loop, waiting for another request to
come from the client. As a result, the ssh session hangs around until
the client process ends, which may be much later (because resolving
deltas, etc, may consume a lot of CPU).
This is bad for two reasons:
- it's consuming resources on the server to leave open a connection
that won't see any more use
- if something bad happens to the ssh connection in the meantime (say,
it gets killed by the network because it's idle, as happened in a
real-world report), then ssh will exit non-zero, and we'll propagate
the error up the stack.
The server is correct here not to hang up after serving the pack. The v2
protocol's design is meant to allow multiple requests like this, and
hanging up would be the wrong thing for a hypothetical client which was
planning to make more requests (though in practice, the git.git client
never would, and I doubt any other implementations would either).
The right thing is instead for the client to signal to the server that
it's not interested in making more requests. We can do that by closing
the pipe descriptor we use to write to ssh. This will propagate to the
server upload-pack as an EOF when it tries to read the next request (and
then it will close its half, and the whole connection will go away).
It's important to do this "half duplex" shutdown, because we have to do
it _before_ we actually receive the pack. This is an artifact of the way
fetch-pack and index-pack (or unpack-objects) interact. We hand the
connection off to index-pack (really, a sideband demuxer which feeds
it), and then wait until it returns. And it doesn't do that until it has
resolved all of the deltas in the pack, even though it was done reading
from the server long before.
So just closing the connection fully after index-pack returns would be
too late; we'd have held it open much longer than was necessary. And
teaching index-pack to close the connection is awkward. It's not even
seeing the whole conversation (the sideband demuxer is, but it doesn't
actually know what's in the packets, or when the end comes).
Note that this close() is happening deep within the transport code. It's
possible that a caller would want to perform other operations over the
same ssh transport after receiving the pack. But as of the current code,
none of the callers do, and there haven't been discussions of any plans
to change this. If we need to support that later, we can probably do so
by passing down a flag for "you're the last request on the transport;
it's OK to close" instead of the code just assuming that's true.
The description above all discusses v2 ssh, so it's worth thinking about
how this interacts with other protocols:
- in v0 protocols, we could do the same half-duplex shutdown (it just
goes into the v0 do_fetch_pack() instead). This does work, but since
it doesn't have the same persistence problem in the first place,
there's little reason to change it at this point.
- local fetches against git-upload-pack on the same machine will
behave the same as ssh (they are talking over two pipes, and see EOF
on their input pipe)
- fetches against git-daemon will run this same code, and close one of
the descriptors. In practice, this won't do anything, since there
our two descriptors are dups of each other, and not part of a
half-duplex pair. The right thing would probably be to call
shutdown(SHUT_WR) on it. I didn't bother with that here. It doesn't
face the same error-code problem (since it's just a TCP connection),
so it's really only an optimization problem. And git:// is not that
widely used these days, and has less impact on server resources than
an ssh termination.
- v2 http doesn't suffer from this problem in the first place, as our
pipes terminate at a local git-remote-https, which is passing data
along as individual requests via curl. Probably curl is keeping the
TCP/TLS connection open for more requests, and we might be able to
tell it manually "hey, we are done making requests now". But I think
that's much less important. It again doesn't suffer from the
error-code problem, and HTTP keepalive is pretty well understood
(importantly, the timeouts can be set low, because clients like curl
know how to reconnect for subsequent requests if necessary). So it's
probably not worth figuring out how to tell curl that we're done
(though if we do, this patch is probably the first step anyway;
fetch-pack closes the pipe back to remote-https, which would be the
signal that it should tell curl we're done).
The code is pretty straightforward. We close the pipe at the right
moment, and set it to -1 to mark it as invalid. I modified the later
cleanup code to avoid calling close(-1). That's not strictly necessary,
since close(-1) is a noop, but hopefully makes things a bit more obvious
to a reader.
I suspect that trying to call more transport functions after the close()
(e.g., calling transport_fetch_refs() again) would fail, as it's not
smart enough to realize we need to re-open the ssh connection. But
that's already true when v0 is in use. And no current callers want to do
that (and again, the solution is probably a flag in the transport code
to keep things open, which can be added later).
There's no test here, as the situation it covers is inherently racy (the
question is when upload-pack exits, compared to when index-pack finishes
resolving deltas and exits). The rather gross shell snippet below does
recreate the problematic situation; when run on a sufficiently-large
repository (git.git works fine), it kills an "idle" upload-pack while
the client is resolving deltas, leading to a failed clone.
(
git clone --no-local --progress . foo.git 2>&1
echo >&2 "clone exit code=$?"
) |
tr '\r' '\n' |
while read line
do
case "$done,$line" in
,Resolving*)
echo "hit resolving deltas; killing upload-pack"
killall -9 git-upload-pack
done=t
;;
esac
done
Reported-by: Greg Pflaum <greg.pflaum@pnp-hcl.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The code to handle options recently added to "git stash show"
around untracked part of the stash segfaulted when these options
were used on a stash entry that does not record untracked part.
* dl/stash-show-untracked-fixup:
stash show: fix segfault with --{include,only}-untracked
t3905: correct test title
When "git update-ref -d" removes a ref that is packed, it left
empty directories under $GIT_DIR/refs/ for
* wc/packed-ref-removal-cleanup:
refs: cleanup directories when deleting packed ref
"git mailinfo" (hence "git am") learned the "--quoted-cr" option to
control how lines ending with CRLF wrapped in base64 or qp are
handled.
* dd/mailinfo-quoted-cr:
am: learn to process quoted lines that ends with CRLF
mailinfo: allow stripping quoted CR without warning
mailinfo: allow squelching quoted CRLF warning
mailinfo: warn if CRLF found in decoded base64/QP email
mailinfo: stop parsing options manually
mailinfo: load default metainfo_charset lazily
The final part of "parallel checkout".
* mt/parallel-checkout-part-3:
ci: run test round with parallel-checkout enabled
parallel-checkout: add tests related to .gitattributes
t0028: extract encoding helpers to lib-encoding.sh
parallel-checkout: add tests related to path collisions
parallel-checkout: add tests for basic operations
checkout-index: add parallel checkout support
builtin/checkout.c: complete parallel checkout support
make_transient_cache_entry(): optionally alloc from mem_pool
"git push" learns to discover common ancestor with the receiving
end over protocol v2.
* jt/push-negotiation:
send-pack: support push negotiation
fetch: teach independent negotiation (no packfile)
fetch-pack: refactor command and capability write
fetch-pack: refactor add_haves()
fetch-pack: refactor process_acks()
"git add -i --dry-run" does not dry-run, which was surprising. The
combination of options has taught to error out.
* ow/no-dryrun-in-add-i:
add: die if both --dry-run and --interactive are given
"git p4" learned to find branch points more efficiently.
* jk/p4-locate-branch-point-optim:
git-p4: speed up search for branch parent
git-p4: ensure complex branches are cloned correctly
Over-the-wire protocol learns a new request type to ask for object
sizes given a list of object names.
* ba/object-info:
object-info: support for retrieving object info
The word-diff mode has been taught to work better with a word
regexp that can match an empty string.
* pw/word-diff-zero-width-matches:
word diff: handle zero length matches
When `git stash show --include-untracked` or
`git stash show --only-untracked` is run on a stash that doesn't include
an untracked entry, a segfault occurs. This happens because we do not
check whether the untracked entry is actually present and just attempt
to blindly dereference it.
Ensure that the untracked entry is present before actually attempting to
dereference it.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We reference the non-existent option `git stash show --show-untracked`
when we really meant `--only-untracked`. Correct the test title
accordingly.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Fixes two memory leaks when running `git maintenance start` or `git
maintenance stop` in `update_background_schedule`:
$ valgrind --leak-check=full ~/git/bin/git maintenance start
==76584== Memcheck, a memory error detector
==76584== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==76584== Using Valgrind-3.16.1 and LibVEX; rerun with -h for copyright info
==76584== Command: /home/lenaic/git/bin/git maintenance start
==76584==
==76584==
==76584== HEAP SUMMARY:
==76584== in use at exit: 34,880 bytes in 252 blocks
==76584== total heap usage: 820 allocs, 568 frees, 146,414 bytes allocated
==76584==
==76584== 65 bytes in 1 blocks are definitely lost in loss record 17 of 39
==76584== at 0x483E6AF: malloc (vg_replace_malloc.c:306)
==76584== by 0x3DC39C: xrealloc (wrapper.c:126)
==76584== by 0x3992CC: strbuf_grow (strbuf.c:98)
==76584== by 0x39A473: strbuf_vaddf (strbuf.c:392)
==76584== by 0x39BC54: xstrvfmt (strbuf.c:979)
==76584== by 0x39BD2C: xstrfmt (strbuf.c:989)
==76584== by 0x18451B: update_background_schedule (gc.c:1977)
==76584== by 0x1846F6: maintenance_start (gc.c:2011)
==76584== by 0x1847B4: cmd_maintenance (gc.c:2030)
==76584== by 0x127A2E: run_builtin (git.c:453)
==76584== by 0x127E81: handle_builtin (git.c:704)
==76584== by 0x128142: run_argv (git.c:771)
==76584==
==76584== 240 bytes in 1 blocks are definitely lost in loss record 29 of 39
==76584== at 0x4840D7B: realloc (vg_replace_malloc.c:834)
==76584== by 0x491CE5D: getdelim (in /usr/lib/libc-2.33.so)
==76584== by 0x39ADD7: strbuf_getwholeline (strbuf.c:635)
==76584== by 0x39AF31: strbuf_getdelim (strbuf.c:706)
==76584== by 0x39B064: strbuf_getline_lf (strbuf.c:727)
==76584== by 0x184273: crontab_update_schedule (gc.c:1919)
==76584== by 0x184678: update_background_schedule (gc.c:1997)
==76584== by 0x1846F6: maintenance_start (gc.c:2011)
==76584== by 0x1847B4: cmd_maintenance (gc.c:2030)
==76584== by 0x127A2E: run_builtin (git.c:453)
==76584== by 0x127E81: handle_builtin (git.c:704)
==76584== by 0x128142: run_argv (git.c:771)
==76584==
==76584== LEAK SUMMARY:
==76584== definitely lost: 305 bytes in 2 blocks
==76584== indirectly lost: 0 bytes in 0 blocks
==76584== possibly lost: 0 bytes in 0 blocks
==76584== still reachable: 34,575 bytes in 250 blocks
==76584== suppressed: 0 bytes in 0 blocks
==76584== Reachable blocks (those to which a pointer was found) are not shown.
==76584== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==76584==
==76584== For lists of detected and suppressed errors, rerun with: -s
==76584== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)
Signed-off-by: Lénaïc Huard <lenaic@lhuard.fr>
Acked-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The way the command line specified by the trailer.<token>.command
configuration variable receives the end-user supplied value was
both error prone and misleading. An alternative to achieve the
same goal in a safer and more intuitive way has been added, as
the trailer.<token>.cmd configuration variable, to replace it.
* zh/trailer-cmd:
trailer: add new .cmd config option
docs: correct descript of trailer.<token>.command
Various test and documentation updates about .gitsomething paths
that are symlinks.
* jk/symlinked-dotgitx-cleanup:
docs: document symlink restrictions for dot-files
fsck: warn about symlinked dotfiles we'll open with O_NOFOLLOW
t0060: test ntfs/hfs-obscured dotfiles
t7450: test .gitmodules symlink matching against obscured names
t7450: test verify_path() handling of gitmodules
t7415: rename to expand scope
fsck_tree(): wrap some long lines
fsck_tree(): fix shadowed variable
t7415: remove out-dated comment about translation
Options to "git pack-objects" that take numeric values like
--window and --depth should not accept negative values; the input
validation has been tightened.
* jk/pack-objects-negative-options-fix:
pack-objects: clamp negative depth to 0
t5316: check behavior of pack-objects --depth=0
pack-objects: clamp negative window size to 0
t5300: check that we produced expected number of deltas
t5300: modernize basic tests
"git submodule update --quiet" did not propagate the quiet option
down to underlying "git fetch", which has been corrected.
* nc/submodule-update-quiet:
submodule update: silence underlying fetch with "--quiet"
A few variants of informational message "Already up-to-date" has
been rephrased.
* js/merge-already-up-to-date-message-reword:
merge: fix swapped "up to date" message components
merge(s): apply consistent punctuation to "up to date" messages
"git bisect skip" when custom words are used for new/old did not
work, which has been corrected.
* rj/bisect-skip-honor-terms:
bisect--helper: use BISECT_TERMS in 'bisect skip' command
When deleting a packed ref via 'update-ref -d', a lockfile is made in
the directory that would contain the loose copy of that ref, creating
any directories in the ref's path that do not exist. When the
transaction completes, the lockfile is deleted, but any empty parent
directories made when creating the lockfile are left in place. These
empty directories are not removed by 'pack-refs' or other housekeeping
tasks and will accumulate over time.
When deleting a loose ref, we remove all empty parent directories at the
end of the transaction.
This commit applies the parent directory cleanup logic used when
deleting loose refs to packed refs as well.
Signed-off-by: Will Chandler <wfc@wfchandler.org>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The word "renamed" has two possible translations in many European
languages depending on whether one thing was renamed or two things were
renamed. Give translators freedom to alter any part of the message to
make it sound right in their language.
Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Acked-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git repack -A -d" in a partial clone unnecessarily loosened
objects in promisor pack.
* rs/repack-without-loosening-promised-objects:
repack: avoid loosening promisor objects in partial clones
"git subtree" updates.
* ls/subtree: (30 commits)
subtree: be stricter about validating flags
subtree: push: allow specifying a local rev other than HEAD
subtree: allow 'split' flags to be passed to 'push'
subtree: allow --squash to be used with --rejoin
subtree: give the docs a once-over
subtree: have $indent actually affect indentation
subtree: don't let debug and progress output clash
subtree: add comments and sanity checks
subtree: remove duplicate check
subtree: parse revs in individual cmd_ functions
subtree: use "^{commit}" instead of "^0"
subtree: don't fuss with PATH
subtree: use "$*" instead of "$@" as appropriate
subtree: use more explicit variable names for cmdline args
subtree: use git-sh-setup's `say`
subtree: use `git merge-base --is-ancestor`
subtree: drop support for git < 1.7
subtree: more consistent error propagation
subtree: don't have loose code outside of a function
subtree: t7900: add porcelain tests for 'pull' and 'push'
...
SHA-256 transition.
* bc/hash-transition-interop-part-1:
hex: print objects using the hash algorithm member
hex: default to the_hash_algo on zero algorithm value
builtin/pack-objects: avoid using struct object_id for pack hash
commit-graph: don't store file hashes as struct object_id
builtin/show-index: set the algorithm for object IDs
hash: provide per-algorithm null OIDs
hash: set, copy, and use algo field in struct object_id
builtin/pack-redundant: avoid casting buffers to struct object_id
Use the final_oid_fn to finalize hashing of object IDs
hash: add a function to finalize object IDs
http-push: set algorithm when reading object ID
Always use oidread to read into struct object_id
hash: add an algo member to struct object_id
In previous changes, mailinfo has learnt to process lines that decoded
from base64 or quoted-printable, and ends with CRLF.
Let's teach "am" that new trick, too.
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In previous changes, we've turned on warning for quoted CR in base64 or
quoted-printable email messages. Some projects see those quoted CR a lot,
they know that it happens most of the time, and they find it's desirable
to always strip those CR.
Those projects in question usually fall back to use other tools to handle
patches when receive such patches.
Let's help those projects handle those patches by stripping those
excessive CR.
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In previous change, Git starts to warn for quoted CRLF in decoded
base64/QP email. Despite those warnings are usually helpful,
quoted CRLF could be part of some users' workflow.
Let's give them an option to turn off the warning completely.
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When SMTP servers receive 8-bit email messages, possibly with only
LF as line ending, some of them decide to change said LF to CRLF.
Some mailing list softwares, when receive 8-bit email messages,
decide to encode those messages in base64 or quoted-printable.
If an email is transfered through above mail servers, then distributed
by such mailing list softwares, the recipients will receive an email
contains a patch mungled with CRLF encoded inside another encoding.
Thus, such CR (in CRLF) couldn't be dropped by "mailsplit".
Hence, the mailed patch couldn't be applied cleanly.
Such accidents have been observed in the wild [1].
Instead of silently rejecting those messages, let's give our users
some warnings if such CR (as part of CRLF) is found.
[1]: https://nmbug.notmuchmail.org/nmweb/show/m2lf9ejegj.fsf%40guru.guru-group.fi
Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The description of "%ch" is missing a space after "human style", before
the parenthetical remark. This description was introduced in b722d4560e
("pretty: provide human date format", 2021-04-25). That commit also
added "%ah", which does have the space already.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Drop the ")" at the end of this paragraph. There's a parenthetical
remark in this paragraph, but it's been closed on the line above.
Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Portability fix for command line completion script (in contrib/).
* si/zsh-complete-comment-fix:
work around zsh comment in __git_complete_worktree_paths
Further update the command line completion (in contrib/) for "git
stash".
* dl/complete-stash-updates:
git-completion.bash: consolidate cases in _git_stash()
git-completion.bash: use $__git_cmd_idx in more places
git-completion.bash: rename to $__git_cmd_idx
git-completion.bash: separate some commands onto their own line
The command line completion (in contrib/) for "git stash" has been
updated.
* dl/complete-stash:
git-completion.bash: use __gitcomp_builtin() in _git_stash()
git-completion.bash: extract from else in _git_stash()
git-completion.bash: pass $__git_subcommand_idx from __git_main()
Jeff King
Junio C Hamano
Denton Liu
Louis Sautier
Lénaïc Huard
Will Chandler
Alex Henrie
Đoàn Trần Công Danh
Martin Ågren