view hgext/pager.py @ 45685:57b5452a55d5

pyoxidizer: produce working Python 3 Windows installers (issue6366)

While we've had code to produce Python 3 Windows installers with
PyOxidizer, we haven't been advertising them on the web site due to
a bug in making TLS connections and issues around resource handling.

This commit upgrades our PyOxidizer install and configuration to
use a recent Git commit of PyOxidizer. This new version of PyOxidizer
contains a *ton* of changes, improvements, and bug fixes. Notably,
Windows shared distributions now mostly "just work" and the TLS bug
and random problems with Python extension modules in the standard
library go away. And Python has been upgraded from 3.7 to 3.8.6.

The price we pay for this upgrade is a ton of backwards incompatible
changes to Starlark.

I applied this commit (the overall series actually) on stable to
produce Windows installers for Mercurial 5.5.2, which I published
shortly before submitting this commit for review.

In order to get the stable branch working, I decided to take a
less aggressive approach to Python resource management. Previously,
we were attempting to load all Python modules from memory and were
performing some hacks to copy Mercurial's non-module resources
into additional directories in Starlark. This commit implements
a resource callback function in Starlark (a new feature since
PyOxidizer 0.7) to dynamically assign standard library resources
to in-memory loading and all other resources to filesystem loading.
This means that Mercurial's files and all the other packages we ship
in the Windows installers (e.g. certifi and pygments) are loaded
from the filesystem instead of from memory. This avoids issues
due to lack of __file__ and enables us to ship a working Python
3 installer on Windows.

The end state of the install layout after this patch is not
ideal for @: we still copy resource files like templates and
help text to directories next to the hg.exe executable. There
is code in @ to use importlib.resources to load these files and
we could likely remove these copies once this lands on @. But for
now, the install layout mimics what we've shipped for seemingly
forever and is backwards compatible. It allows us to achieve the
milestone of working Python 3 Windows installers and gets us a
giant step closer to deleting Python 2.

Differential Revision: https://phab.mercurial-scm.org/D9148

# 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 = b'ships-with-hg-core'

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

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


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

            for cmd in cmds:
                var = b'attend-%s' % cmd
                if ui.config(b'pager', var, None):
                    usepager = ui.configbool(b'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(b'pager', b'ignore', b'', b'pager')
                ui.pager(b'extension-via-attend-' + cmd)
            else:
                ui.disablepager()
        return orig(ui, options, cmd, cmdfunc)

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


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