This is an archive of the discontinued Mercurial Phabricator instance.

Differential D8203

logtoprocess: avoid traceback when running long commands
ClosedPublic

Authored by valentin.gatienbaron on Mar 2 2020, 3:00 PM.

Details

Reviewers
None
Group Reviewers
hg-reviewers
Commits
rHG7c0b8652fd8c: logtoprocess: avoid traceback when running long commands
rHG69392460f7b1: logtoprocess: avoid traceback when running long commands
Summary

$ hg log -r "present($(yes | tr -d '\n' | head -c 130000))" "$(yes | tr -d '\n' | head -c 5000)" --config extensions.logtoprocess= --config logtoprocess.commandfinish=whatever
Traceback (most recent call last):

File "/usr/bin/hg", line 67, in <module>
  dispatch.run()
File "/usr/lib64/python2.7/site-packages/mercurial/dispatch.py", line 111, in run
  status = dispatch(req)
File "/usr/lib64/python2.7/site-packages/mercurial/dispatch.py", line 290, in dispatch
  canonical_command=req.canonical_command,
File "/usr/lib64/python2.7/site-packages/mercurial/ui.py", line 1991, in log
  logger.log(self, event, msg, opts)
File "/usr/lib64/python2.7/site-packages/hgext/logtoprocess.py", line 72, in log
  procutil.runbgcommand(script, fullenv, shell=True)
File "/usr/lib64/python2.7/site-packages/mercurial/utils/procutil.py", line 597, in runbgcommand
  b'error running %r: %s' % (cmd, os.strerror(returncode)),

OSError: [Errno 7] error running 'whatever': Argument list too long

This can happen if you pass a bunch of filenames to hg commit, for instance.

This is due to a size limit on individual env vars (on linux, but I
imagine there are similar limits in other OSes):
$ FOO=$(yes | head -c 131000) /usr/bin/true
$ FOO=$(yes | head -c 132000) /usr/bin/true
-bash: /usr/bin/true: Argument list too long

I propose to avoid this by truncating the message. I didn't make the
limit configurable as it doesn't seem particularly convenient to
customize this. I'm not sure if various OSes would want radically
different limits here?

Diff Detail

Repository
rHG Mercurial
Branch
default
Lint
No Linters Available
Unit
No Unit Test Coverage

Revision Contents
Changeset List

PathPackages
Mhgext/logtoprocess.py (7 lines)

Diff 20414

hgext/logtoprocess.py

def __init__(self, ui): def __init__(self, ui):
self._scripts = dict(ui.configitems(b'logtoprocess')) self._scripts = dict(ui.configitems(b'logtoprocess'))
def tracked(self, event): def tracked(self, event):
return bool(self._scripts.get(event)) return bool(self._scripts.get(event))
def log(self, ui, event, msg, opts): def log(self, ui, event, msg, opts):
script = self._scripts[event] script = self._scripts[event]
maxmsg = 100000
if len(msg) > maxmsg:
# Each env var has a 128KiB limit on linux. msg can be long, in
# particular for command event, where it's the full command line.
# Prefer truncating the message than raising "Argument list too
# long" error.
msg = msg[:maxmsg] + ' (truncated)'
env = { env = {
b'EVENT': event, b'EVENT': event,
b'HGPID': os.getpid(), b'HGPID': os.getpid(),
b'MSG1': msg, b'MSG1': msg,
} }
# keyword arguments get prefixed with OPT_ and uppercased # keyword arguments get prefixed with OPT_ and uppercased
env.update( env.update(
(b'OPT_%s' % key.upper(), value) for key, value in opts.items() (b'OPT_%s' % key.upper(), value) for key, value in opts.items()
) )
fullenv = procutil.shellenviron(env) fullenv = procutil.shellenviron(env)
procutil.runbgcommand(script, fullenv, shell=True) procutil.runbgcommand(script, fullenv, shell=True)
def uipopulate(ui): def uipopulate(ui):
ui.setlogger(b'logtoprocess', processlogger(ui)) ui.setlogger(b'logtoprocess', processlogger(ui))