Mercurial > hg
view mercurial/txnutil.py @ 38162:bdf344aea0ee
extensions: peek command table of disabled extensions without importing
With chg where demandimport disabled, and if disk cache not warm, it took
more than 5 seconds to get "unknown command" error when you typo a command
name. This is horrible UX.
The new implementation is less accurate than the original one as Python
can do anything at import time and cmdtable may be imported from another
module, but I think it's good enough.
Note that the new implementation has to parse .py files, which is slightly
slower than executing .pyc if demandimport is enabled.
author | Yuya Nishihara <yuya@tcha.org> |
---|---|
date | Thu, 03 May 2018 18:38:02 +0900 |
parents | 206532700213 |
children | 2372284d9457 |
line wrap: on
line source
# txnutil.py - transaction related utilities # # Copyright FUJIWARA Katsunori <foozy@lares.dti.ne.jp> and others # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import errno from . import ( encoding, ) def mayhavepending(root): '''return whether 'root' may have pending changes, which are visible to this process. ''' return root == encoding.environ.get('HG_PENDING') def trypending(root, vfs, filename, **kwargs): '''Open file to be read according to HG_PENDING environment variable This opens '.pending' of specified 'filename' only when HG_PENDING is equal to 'root'. This returns '(fp, is_pending_opened)' tuple. ''' if mayhavepending(root): try: return (vfs('%s.pending' % filename, **kwargs), True) except IOError as inst: if inst.errno != errno.ENOENT: raise return (vfs(filename, **kwargs), False)