revisionbranchcache: fall back to slow path if starting readonly (issue4531)
Transitioning to Mercurial versions with revision branch cache could be slow as
long as all operations were readonly (revset queries) and the cache would be
populated but not written back.
Instead, fall back to using the consistently slow path when readonly and the
cache doesn't exist yet. That avoids the overhead of populating the cache
without writing it back.
If not readonly, it will still populate all missing entries initially. That
avoids repeated writing of the cache file with small updates, and it also makes
sure a fully populated cache available for the readonly operations.
#!/usr/bin/env python
from mercurial import demandimport
demandimport.enable()
import sys
from mercurial.i18n import _
from mercurial import simplemerge, fancyopts, util, ui
options = [('L', 'label', [], _('labels to use on conflict markers')),
('a', 'text', None, _('treat all files as text')),
('p', 'print', None,
_('print results instead of overwriting LOCAL')),
('', 'no-minimal', None, _('no effect (DEPRECATED)')),
('h', 'help', None, _('display help and exit')),
('q', 'quiet', None, _('suppress output'))]
usage = _('''simplemerge [OPTS] LOCAL BASE OTHER
Simple three-way file merge utility with a minimal feature set.
Apply to LOCAL the changes necessary to go from BASE to OTHER.
By default, LOCAL is overwritten with the results of this operation.
''')
class ParseError(Exception):
"""Exception raised on errors in parsing the command line."""
def showhelp():
sys.stdout.write(usage)
sys.stdout.write('\noptions:\n')
out_opts = []
for shortopt, longopt, default, desc in options:
out_opts.append(('%2s%s' % (shortopt and '-%s' % shortopt,
longopt and ' --%s' % longopt),
'%s' % desc))
opts_len = max([len(opt[0]) for opt in out_opts])
for first, second in out_opts:
sys.stdout.write(' %-*s %s\n' % (opts_len, first, second))
try:
for fp in (sys.stdin, sys.stdout, sys.stderr):
util.setbinary(fp)
opts = {}
try:
args = fancyopts.fancyopts(sys.argv[1:], options, opts)
except fancyopts.getopt.GetoptError, e:
raise ParseError(e)
if opts['help']:
showhelp()
sys.exit(0)
if len(args) != 3:
raise ParseError(_('wrong number of arguments'))
sys.exit(simplemerge.simplemerge(ui.ui(), *args, **opts))
except ParseError, e:
sys.stdout.write("%s: %s\n" % (sys.argv[0], e))
showhelp()
sys.exit(1)
except util.Abort, e:
sys.stderr.write("abort: %s\n" % e)
sys.exit(255)
except KeyboardInterrupt:
sys.exit(255)