logtoprocess: avoid traceback when running long commands
$ 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?
Differential Revision: https://phab.mercurial-scm.org/D8203
--- a/hgext/logtoprocess.py Mon Feb 24 17:57:57 2020 +0100
+++ b/hgext/logtoprocess.py Mon Mar 02 14:36:20 2020 -0500
@@ -59,6 +59,13 @@
def log(self, ui, event, msg, opts):
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 = {
b'EVENT': event,
b'HGPID': os.getpid(),