hgext/children.py

cmdutil: make in-memory changes visible to external editor (issue4378)

Before this patch, external editor process for the commit log can't
view some in-memory changes (especially, of dirstate), because they
aren't written out until the end of transaction (or wlock).

This causes unexpected output of Mercurial commands spawned from that
editor process.

To make in-memory changes visible to external editor process, this
patch does:

  - write (or schedule to write) in-memory dirstate changes, and
  - set HG_PENDING environment variable, if:
    - a transaction is running, and
    - there are in-memory changes to be visible

"hg diff" spawned from external editor process for "hg qrefresh"
shows:

  - "changes newly imported into the topmost" before 49148d7868df(*)
  - "all changes recorded in the topmost by refreshing" after this patch

(*) 49148d7868df changed steps invoking editor process

Even though backward compatibility may be broken, the latter behavior
looks reasonable, because "hg diff" spawned from the editor process
consistently shows "what changes new revision records" regardless of
invocation context.

In fact, issue4378 itself should be resolved by 800e090e9c64, which
made 'repo.transaction()' write in-memory dirstate changes out
explicitly before starting transaction. It also made "hg qrefresh"
imply 'dirstate.write()' before external editor invocation in call
chain below.

  - mq.queue.refresh
    - strip.strip
      - repair.strip
        - localrepository.transaction
          - dirstate.write
    - localrepository.commit
      - invoke external editor

Though, this patch has '(issue4378)' in own summary line to indicate
that issues like issue4378 should be fixed by this.

BTW, this patch adds '-m' option to a 'hg ci --amend' execution in
'test-commit-amend.t', to avoid invoking external editor process.

In this case, "unsure" states may be changed to "clean" according to
timestamp or so on. These changes should be written into pending file,
if external editor invocation is required,

Then, writing dirstate changes out breaks stability of test, because
it shows "transaction abort!/rollback completed" occasionally.

Aborting after editor process invocation while commands below may
cause similar instability of tests, too (AFAIK, there is no more such
one, at this revision)

  - commit --amend
    - without --message/--logfile

  - import
    - without --message/--logfile,
    - without --no-commit,
    - without --bypass,
    - one of below, and
      - patch has no description text, or
      - with --edit
    - aborting at the 1st patch, which adds or removes file(s)
      - if it only changes existing files, status is checked only for
        changed files by 'scmutil.matchfiles()', and transition from
        "unsure" to "normal" in dirstate doesn't occur (= dirstate
        isn't changed, and written out)
      - aborting at the 2nd or later patch implies other pending
        changes (e.g. changelog), and always causes showing
        "transaction abort!/rollback completed"

# Mercurial extension to provide the 'hg children' command
#
# Copyright 2007 by Intevation GmbH <[e-mail]>
#
# Author(s):
# Thomas Arendsen Hein <[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.

'''command to display child changesets (DEPRECATED)

This extension is deprecated. You should use :hg:`log -r
"children(REV)"` instead.
'''

from mercurial import cmdutil
from mercurial.commands import templateopts
from mercurial.i18n import _

cmdtable = {}
command = cmdutil.command(cmdtable)
# Note for extension authors: ONLY specify testedwith = 'internal' 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 = 'internal'

@command('children',
    [('r', 'rev', '',
     _('show children of the specified revision'), _('REV')),
    ] + templateopts,
    _('hg children [-r REV] [FILE]'),
    inferrepo=True)
def children(ui, repo, file_=None, **opts):
    """show the children of the given or working directory revision

    Print the children of the working directory's revisions. If a
    revision is given via -r/--rev, the children of that revision will
    be printed. If a file argument is given, revision in which the
    file was last changed (after the working directory revision or the
    argument to --rev if given) is printed.
    """
    rev = opts.get('rev')
    if file_:
        fctx = repo.filectx(file_, changeid=rev)
        childctxs = [fcctx.changectx() for fcctx in fctx.children()]
    else:
        ctx = repo[rev]
        childctxs = ctx.children()

    displayer = cmdutil.show_changeset(ui, repo, opts)
    for cctx in childctxs:
        displayer.show(cctx)
    displayer.close()