localrepo: stop doing special dirstate backup at transaction open
Since the dirstate writes are already managed by the transaction, we already do
a backup of the dirstate when necessary (and even trigger one to keep `hg
rollback` happy).
We needs some special code to deal with the initial empty checkout, but it is
not too complicated.
Managing variable filename (as dirstate-v2 uses) at the "journalfile" level, is
complex and fragile (which is consistent with the fact these files are not
journal…). If we no longer do it, our life is significantly simpler.
In some sense, we apply the xkcd-1134¹ solution to our savebackup/restorebackup
problem.
[1] https://xkcd.com/1134/
(the change to test-hardlink are expect as decreasing the number of duplicated
backup drive the hardlink count down)
# logexceptions.py - Write files containing info about Mercurial exceptions
#
# Copyright 2017 Olivia Mackall <olivia@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
import inspect
import os
import sys
import traceback
import uuid
from mercurial import (
dispatch,
extensions,
)
def handleexception(orig, ui):
res = orig(ui)
if not ui.environ.get(b'HGEXCEPTIONSDIR'):
return res
dest = os.path.join(
ui.environ[b'HGEXCEPTIONSDIR'], str(uuid.uuid4()).encode('ascii')
)
exc_type, exc_value, exc_tb = sys.exc_info()
stack = []
tb = exc_tb
while tb:
stack.append(tb)
tb = tb.tb_next
stack.reverse()
hgframe = 'unknown'
hgline = 'unknown'
# Find the first Mercurial frame in the stack.
for tb in stack:
mod = inspect.getmodule(tb)
if not mod.__name__.startswith(('hg', 'mercurial')):
continue
frame = tb.tb_frame
try:
with open(inspect.getsourcefile(tb), 'r') as fh:
hgline = fh.readlines()[frame.f_lineno - 1].strip()
except (IndexError, OSError):
pass
hgframe = '%s:%d' % (frame.f_code.co_filename, frame.f_lineno)
break
primary = traceback.extract_tb(exc_tb)[-1]
primaryframe = '%s:%d' % (primary.filename, primary.lineno)
with open(dest, 'wb') as fh:
parts = [
str(exc_value),
primaryframe,
hgframe,
hgline,
ui.environ[b'TESTNAME'].decode('utf-8', 'replace'),
]
fh.write(b'\0'.join(p.encode('utf-8', 'replace') for p in parts))
def extsetup(ui):
extensions.wrapfunction(dispatch, 'handlecommandexception', handleexception)