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Differential D8203

logtoprocess: avoid traceback when running long commands
ClosedPublic

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

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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

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rHG Mercurial
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default
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PathPackages
Mhgext/logtoprocess.py (7 lines)

Diff 20415

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] + b' (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))