view mercurial/help/hg.1.txt @ 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

====
 hg
====

---------------------------------------
Mercurial source code management system
---------------------------------------

:Author:         Matt Mackall <[e-mail]>
:Organization:   Mercurial
:Manual section: 1
:Manual group:   Mercurial Manual

.. contents::
   :backlinks: top
   :class: htmlonly
   :depth: 1


Synopsis
""""""""
**hg** *command* [*option*]... [*argument*]...

Description
"""""""""""
The **hg** command provides a command line interface to the Mercurial
system.

Command Elements
""""""""""""""""

files...
    indicates one or more filename or relative path filenames; see
    `File Name Patterns`_ for information on pattern matching

path
    indicates a path on the local machine

revision
    indicates a changeset which can be specified as a changeset
    revision number, a tag, or a unique substring of the changeset
    hash value

repository path
    either the pathname of a local repository or the URI of a remote
    repository.

.. include:: hg.1.gendoc.txt

Files
"""""

``/etc/mercurial/hgrc``, ``$HOME/.hgrc``, ``.hg/hgrc``
    This file contains defaults and configuration. Values in
    ``.hg/hgrc`` override those in ``$HOME/.hgrc``, and these override
    settings made in the global ``/etc/mercurial/hgrc`` configuration.
    See |hgrc(5)|_ for details of the contents and format of these
    files.

``.hgignore``
    This file contains regular expressions (one per line) that
    describe file names that should be ignored by **hg**. For details,
    see |hgignore(5)|_.

``.hgsub``
    This file defines the locations of all subrepositories, and
    tells where the subrepository checkouts came from. For details, see
    :hg:`help subrepos`.

``.hgsubstate``
    This file is where Mercurial stores all nested repository states. *NB: This
    file should not be edited manually.*

``.hgtags``
    This file contains changeset hash values and text tag names (one
    of each separated by spaces) that correspond to tagged versions of
    the repository contents. The file content is encoded using UTF-8.

``.hg/last-message.txt``
    This file is used by :hg:`commit` to store a backup of the commit message
    in case the commit fails.

``.hg/localtags``
    This file can be used to define local tags which are not shared among
    repositories. The file format is the same as for ``.hgtags``, but it is
    encoded using the local system encoding.

Some commands (e.g. revert) produce backup files ending in ``.orig``,
if the ``.orig`` file already exists and is not tracked by Mercurial,
it will be overwritten.

Bugs
""""
Probably lots, please post them to the mailing list (see Resources_
below) when you find them.

See Also
""""""""
|hgignore(5)|_, |hgrc(5)|_

Author
""""""
Written by Matt Mackall <[e-mail]>

Resources
"""""""""
Main Web Site: https://mercurial-scm.org/

Source code repository: https://www.mercurial-scm.org/repo/hg

Mailing list: https://www.mercurial-scm.org/mailman/listinfo/mercurial/

Copying
"""""""
Copyright (C) 2005-2019 Matt Mackall.
Free use of this software is granted under the terms of the GNU General
Public License version 2 or any later version.

.. include:: common.txt