view hgext/bookflow.py @ 42377:0546ead39a7e stable

manifest: avoid corruption by dropping removed files with pure (issue5801)

Previously, removed files would simply be marked by overwriting the first byte
with NUL and dropping their entry in `self.position`.  But no effort was made to
ignore them when compacting the dictionary into text form.  This allowed them to
slip into the manifest revision, since the code seems to be trying to minimize
the string operations by copying as large a chunk as possible.  As part of this,
compact() walks the existing text based on entries in the `positions` list, and
consumed everything up to the next position entry.   This typically resulted in
a ValueError complaining about unsorted manifest entries.

Sometimes it seems that files do get dropped in large repos- it seems to
correspond to there being a new entry that would take the same slot.  A much
more trivial problem is that if the only changes were removals, `_compact()`
didn't even run because `__delitem__` doesn't add anything to `self.extradata`.
Now there's an explicit variable to flag this, both to allow `_compact()` to
run, and to avoid searching the manifest in cases where there are no removals.

In practice, this behavior was mostly obscured by the check in fastdelta() which
takes a different path that explicitly drops removed files if there are fewer
than 1000 changes.  However, timeless has a repo where after rebasing tens of
commits, a totally different path[1] is taken that bypasses the change count
check and hits this problem.

[1] https://www.mercurial-scm.org/repo/hg/file/2338bdea4474/mercurial/manifest.py#l1511

"""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 = 'bookflow'

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

configitem(MY_NAME, 'protect', ['@'])
configitem(MY_NAME, 'require-bookmark', True)
configitem(MY_NAME, '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, 'protect'):
            raise error.Abort(
                _('cannot commit, bookmark %s is protected') % active)
        if not cwd_at_bookmark(repo, active):
            raise error.Abort(
       _('cannot commit, working directory out of sync with active bookmark'),
                hint=_("run 'hg up %s'") % active)
    elif ui.configbool(MY_NAME, 'require-bookmark', True):
        raise error.Abort(_('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(_(
                    "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(_(
            "working directory out of sync with active bookmark, run "
            "'hg up %s'"
        ) % active)
    return rc

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

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