hgext/pager.py

sshpeer: support not reading and forwarding stderr

The "doublepipe" primitive as used by sshpeer will automatically read
from stderr and forward output to the local ui.

This poses problems for deterministic testing because reads may not
be consistent. For example, the server may not be done sending all
output to stderr and the client will perform different numbers of
read operations or will read from stderr and stdout at different times.

To make tests deterministic, we'll need to disable the "doublepipe"
primitive and perform stderr I/O explicitly. We add an argument to the
sshpeer constructor to disable the use of the doublepipe.

Differential Revision: https://phab.mercurial-scm.org/D2467

# pager.py - display output using a pager
#
# Copyright 2008 David Soria Parra <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
#
# To load the extension, add it to your configuration file:
#
#   [extension]
#   pager =
#
# Run 'hg help pager' to get info on configuration.

'''browse command output with an external pager (DEPRECATED)

Forcibly enable paging for individual commands that don't typically
request pagination with the attend-<command> option. This setting
takes precedence over ignore options and defaults::

  [pager]
  attend-cat = false
'''
from __future__ import absolute_import

from mercurial import (
    cmdutil,
    commands,
    dispatch,
    extensions,
    registrar,
    )

# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = 'ships-with-hg-core'

configtable = {}
configitem = registrar.configitem(configtable)

configitem('pager', 'attend',
        default=lambda: attended,
)

def uisetup(ui):

    def pagecmd(orig, ui, options, cmd, cmdfunc):
        auto = options['pager'] == 'auto'
        if auto and not ui.pageractive:
            usepager = False
            attend = ui.configlist('pager', 'attend')
            ignore = ui.configlist('pager', 'ignore')
            cmds, _ = cmdutil.findcmd(cmd, commands.table)

            for cmd in cmds:
                var = 'attend-%s' % cmd
                if ui.config('pager', var, None):
                    usepager = ui.configbool('pager', var, True)
                    break
                if (cmd in attend or
                     (cmd not in ignore and not attend)):
                    usepager = True
                    break

            if usepager:
                # Slight hack: the attend list is supposed to override
                # the ignore list for the pager extension, but the
                # core code doesn't know about attend, so we have to
                # lobotomize the ignore list so that the extension's
                # behavior is preserved.
                ui.setconfig('pager', 'ignore', '', 'pager')
                ui.pager('extension-via-attend-' + cmd)
            else:
                ui.disablepager()
        return orig(ui, options, cmd, cmdfunc)

    extensions.wrapfunction(dispatch, '_runcommand', pagecmd)

attended = ['annotate', 'cat', 'diff', 'export', 'glog', 'log', 'qdiff']