hgext/fsmonitor/watchmanclient.py

tests: duplicate test for pager for old extension and for in-core pager

When the old pager extension is enabled, I think we should try to be
as BC as reasonable. To help with that, this patch brings back
test-pager.t as of 65a3b4d67a65 (pager: add a test of --pager=no
functionality, 2017-02-06), but under the name test-pager-legacy.t
However, since the behavior has changed in a few cases (notably by no
longer respecting pager.attend), the file is modified to work with the
current version. We will recover some lost BC in coming patches.

Also, to make sure the in-core pager does not depend on the pager
extension being enabled, this patch disables the extension in
test-pager.t. It turns out that pager.attend-$cmd was only supported
when the pager extension was enabled, so the tests are updated to
reflect that. We will need to decide what to do with these.

# watchmanclient.py - Watchman client for the fsmonitor extension
#
# Copyright 2013-2016 Facebook, Inc.
#
# 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 getpass

from mercurial import util

from . import pywatchman

class Unavailable(Exception):
    def __init__(self, msg, warn=True, invalidate=False):
        self.msg = msg
        self.warn = warn
        if self.msg == 'timed out waiting for response':
            self.warn = False
        self.invalidate = invalidate

    def __str__(self):
        if self.warn:
            return 'warning: Watchman unavailable: %s' % self.msg
        else:
            return 'Watchman unavailable: %s' % self.msg

class WatchmanNoRoot(Unavailable):
    def __init__(self, root, msg):
        self.root = root
        super(WatchmanNoRoot, self).__init__(msg)

class client(object):
    def __init__(self, repo, timeout=1.0):
        err = None
        if not self._user:
            err = "couldn't get user"
            warn = True
        if self._user in repo.ui.configlist('fsmonitor', 'blacklistusers'):
            err = 'user %s in blacklist' % self._user
            warn = False

        if err:
            raise Unavailable(err, warn)

        self._timeout = timeout
        self._watchmanclient = None
        self._root = repo.root
        self._ui = repo.ui
        self._firsttime = True

    def settimeout(self, timeout):
        self._timeout = timeout
        if self._watchmanclient is not None:
            self._watchmanclient.setTimeout(timeout)

    def getcurrentclock(self):
        result = self.command('clock')
        if not util.safehasattr(result, 'clock'):
            raise Unavailable('clock result is missing clock value',
                              invalidate=True)
        return result.clock

    def clearconnection(self):
        self._watchmanclient = None

    def available(self):
        return self._watchmanclient is not None or self._firsttime

    @util.propertycache
    def _user(self):
        try:
            return getpass.getuser()
        except KeyError:
            # couldn't figure out our user
            return None

    def _command(self, *args):
        watchmanargs = (args[0], self._root) + args[1:]
        try:
            if self._watchmanclient is None:
                self._firsttime = False
                self._watchmanclient = pywatchman.client(
                    timeout=self._timeout,
                    useImmutableBser=True)
            return self._watchmanclient.query(*watchmanargs)
        except pywatchman.CommandError as ex:
            if 'unable to resolve root' in ex.msg:
                raise WatchmanNoRoot(self._root, ex.msg)
            raise Unavailable(ex.msg)
        except pywatchman.WatchmanError as ex:
            raise Unavailable(str(ex))

    def command(self, *args):
        try:
            try:
                return self._command(*args)
            except WatchmanNoRoot:
                # this 'watch' command can also raise a WatchmanNoRoot if
                # watchman refuses to accept this root
                self._command('watch')
                return self._command(*args)
        except Unavailable:
            # this is in an outer scope to catch Unavailable form any of the
            # above _command calls
            self._watchmanclient = None
            raise