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We have started to see the following assert happen in our GitLab CI
pipelines for jobs that use Windows with Meson:
assertion "bc_ctl.arg_max >= LINE_MAX" failed: file "xargs.c", line 512, function: main
The assert in question verifies that we have enough room available to
pass at least `LINE_MAX` many bytes via the command line. The xargs(1)
binary in those jobs comes from Git for Windows, which in turn sources
the binaries from MSYS2, and has the following limits in place:
$ & "C:/Program Files/Git/usr/bin/bash.exe" -l -c 'xargs --show-limits </dev/null'
Your environment variables take up 17373 bytes
POSIX upper limit on argument length (this system): 12579
POSIX smallest allowable upper limit on argument length (all systems): 4096
Maximum length of command we could actually use: 18446744073709546822
Size of command buffer we are actually using: 12579
Maximum parallelism (--max-procs must be no greater): 2147483647
What's interesting to see is the limit of 16 exabits for the maximum
command line length. This value might seem a bit high, and it is indeed
the result of an underflow: our environment is larger than the POSIX
upper limit on argument length, and the value is computed by subtracting
the former from the latter. So what we get is the result of `2^64 -
(17373 - 12579)`.
This makes it clear that the problem here is the size of our environment
variables. A listing sorted by length yields the following result:
$ Get-ChildItem "Env:" |
Sort-Object { $_.Value.Length } -Descending |
Select-Object Name, @{Name="Length"; Expression={$_.Value.Length}}
Name Length
---- ------
GITLAB_FEATURES 6386
Path 706
PSModulePath 229
The GITLAB_FEATURES environment variable makes up for roughly a third of
the complete environment. This variable is a comma-separated list of
features available for the GitLab instance, and seemingly it has been
growing over time as GitLab added more and more features.
Fix the issue by unsetting the environment variable in "ci/lib.sh". This
ensures that the environment variables are now smaller than the upper
limit on argument length again, and that in turn fixes the assert in
xargs(1).
Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git - fast, scalable, distributed revision control system
Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.
Git is an Open Source project covered by the GNU General Public License version 2 (some parts of it are under different licenses, compatible with the GPLv2). It was originally written by Linus Torvalds with help of a group of hackers around the net.
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Many Git online resources are accessible from https://git-scm.com/ including full documentation and Git related tools.
See Documentation/gittutorial.adoc to get started, then see
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Documentation/git-<commandname>.adoc for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with man gittutorial or git help tutorial, and the
documentation of each command with man git-<commandname> or git help <commandname>.
CVS users may also want to read Documentation/gitcvs-migration.adoc
(man gitcvs-migration or git help cvs-migration if git is
installed).
The user discussion and development of Git take place on the Git mailing list -- everyone is welcome to post bug reports, feature requests, comments and patches to git@vger.kernel.org (read Documentation/SubmittingPatches for instructions on patch submission and Documentation/CodingGuidelines).
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The name "git" was given by Linus Torvalds when he wrote the very first version. He described the tool as "the stupid content tracker" and the name as (depending on your mood):
- random three-letter combination that is pronounceable, and not actually used by any common UNIX command. The fact that it is a mispronunciation of "get" may or may not be relevant.
- stupid. contemptible and despicable. simple. Take your pick from the dictionary of slang.
- "global information tracker": you're in a good mood, and it actually works for you. Angels sing, and a light suddenly fills the room.
- "goddamn idiotic truckload of sh*t": when it breaks