hgext/bookflow.py

copies: make mergecopies() distinguish between copies on each side

I find it confusing that most of the dicts returned from
`mergecopies()` have entries specific to one branch of the merge, but
they're still combined into dict. For example, you can't tell if `copy
= {"bar": "foo"}` means that "foo" was copied to "bar" on the first
branch or the second.

It also feels like there are bugs lurking here because we may mistake
which side the copy happened on. However, for most of the dicts, it's
not possible that there is disagreement. For example, `renamedelete`
keeps track of renames that happened on one side of the merge where
the other side deleted the file. There can't be a disagreement there
(because we record that in the `diverge` dict instead). For regular
copies/renames, there can be a disagreement. Let's say file "foo" was
copied to "bar" on one branch and file "baz" was copied to "bar" on
the other. Beacause we only return one `copy` dict, we end up
replacing the `{"bar": "foo"}` entry by `{"bar": "baz"}`. The merge
code (`manifestmerge()`) will then decide that that means "both
renamed from 'baz'". We should probably treat it as a conflict
instead.

The next few patches will make `mergecopies()` return two instances of
most of the returned copies. That will lead to a bit more code (~40
lines), but I think it makes both `copies.mergecopies()` and
`merge.manifestmerge()` clearer.

Differential Revision: https://phab.mercurial-scm.org/D7986

"""implements bookmark-based branching (EXPERIMENTAL)

 - Disables creation of new branches (config: enable_branches=False).
 - Requires an active bookmark on commit (config: require_bookmark=True).
 - Doesn't move the active bookmark on update, only on commit.
 - Requires '--rev' for moving an existing bookmark.
 - Protects special bookmarks (config: protect=@).

 flow related commands

    :hg book NAME: create a new bookmark
    :hg book NAME -r REV: move bookmark to revision (fast-forward)
    :hg up|co NAME: switch to bookmark
    :hg push -B .: push active bookmark
"""
from __future__ import absolute_import

from mercurial.i18n import _
from mercurial import (
    bookmarks,
    commands,
    error,
    extensions,
    registrar,
)

MY_NAME = b'bookflow'

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

configitem(MY_NAME, b'protect', [b'@'])
configitem(MY_NAME, b'require-bookmark', True)
configitem(MY_NAME, b'enable-branches', False)

cmdtable = {}
command = registrar.command(cmdtable)


def commit_hook(ui, repo, **kwargs):
    active = repo._bookmarks.active
    if active:
        if active in ui.configlist(MY_NAME, b'protect'):
            raise error.Abort(
                _(b'cannot commit, bookmark %s is protected') % active
            )
        if not cwd_at_bookmark(repo, active):
            raise error.Abort(
                _(
                    b'cannot commit, working directory out of sync with active bookmark'
                ),
                hint=_(b"run 'hg up %s'") % active,
            )
    elif ui.configbool(MY_NAME, b'require-bookmark', True):
        raise error.Abort(_(b'cannot commit without an active bookmark'))
    return 0


def bookmarks_update(orig, repo, parents, node):
    if len(parents) == 2:
        # called during commit
        return orig(repo, parents, node)
    else:
        # called during update
        return False


def bookmarks_addbookmarks(
    orig, repo, tr, names, rev=None, force=False, inactive=False
):
    if not rev:
        marks = repo._bookmarks
        for name in names:
            if name in marks:
                raise error.Abort(
                    _(
                        b"bookmark %s already exists, to move use the --rev option"
                    )
                    % name
                )
    return orig(repo, tr, names, rev, force, inactive)


def commands_commit(orig, ui, repo, *args, **opts):
    commit_hook(ui, repo)
    return orig(ui, repo, *args, **opts)


def commands_pull(orig, ui, repo, *args, **opts):
    rc = orig(ui, repo, *args, **opts)
    active = repo._bookmarks.active
    if active and not cwd_at_bookmark(repo, active):
        ui.warn(
            _(
                b"working directory out of sync with active bookmark, run "
                b"'hg up %s'"
            )
            % active
        )
    return rc


def commands_branch(orig, ui, repo, label=None, **opts):
    if label and not opts.get('clean') and not opts.get('rev'):
        raise error.Abort(
            _(
                b"creating named branches is disabled and you should use bookmarks"
            ),
            hint=b"see 'hg help bookflow'",
        )
    return orig(ui, repo, label, **opts)


def cwd_at_bookmark(repo, mark):
    mark_id = repo._bookmarks[mark]
    cur_id = repo.lookup(b'.')
    return cur_id == mark_id


def uisetup(ui):
    extensions.wrapfunction(bookmarks, b'update', bookmarks_update)
    extensions.wrapfunction(bookmarks, b'addbookmarks', bookmarks_addbookmarks)
    extensions.wrapcommand(commands.table, b'commit', commands_commit)
    extensions.wrapcommand(commands.table, b'pull', commands_pull)
    if not ui.configbool(MY_NAME, b'enable-branches'):
        extensions.wrapcommand(commands.table, b'branch', commands_branch)