Mercurial > hg
view tests/test-revlog-v2.t @ 47072:4c041c71ec01
revlog: introduce an explicit tracking of what the revlog is about
Since the dawn of time, people have been forced to rely to lossy introspection
of the index filename to determine what the purpose and role of the revlog they
encounter is. This is hacky, error prone, inflexible, abstraction-leaky,
<insert-your-own-complaints-here>.
In f63299ee7e4d Raphaël introduced a new attribute to track this information:
`revlog_kind`. However it is initialized in an odd place and various instances
end up not having it set. In addition is only tracking some of the information
we end up having to introspect in various pieces of code.
So we add a new attribute that holds more data and is more strictly enforced.
This work is done in collaboration with Raphaël.
The `revlog_kind` one will be removed/adapted in the next changeset. We expect
to be able to clean up various existing piece of code and to simplify coming
work around the newer revlog format.
Differential Revision: https://phab.mercurial-scm.org/D10352
author | Pierre-Yves David <pierre-yves.david@octobus.net> |
---|---|
date | Tue, 06 Apr 2021 05:20:24 +0200 |
parents | cc3ad5c3af3b |
children | 3a9f3470922c |
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#require reporevlogstore A repo with unknown revlogv2 requirement string cannot be opened $ hg init invalidreq $ cd invalidreq $ echo exp-revlogv2.unknown >> .hg/requires $ hg log abort: repository requires features unknown to this Mercurial: exp-revlogv2.unknown (see https://mercurial-scm.org/wiki/MissingRequirement for more information) [255] $ cd .. Can create and open repo with revlog v2 requirement $ cat >> $HGRCPATH << EOF > [experimental] > revlogv2 = enable-unstable-format-and-corrupt-my-data > EOF $ hg init empty-repo $ cd empty-repo $ cat .hg/requires dotencode exp-revlogv2.2 fncache persistent-nodemap (rust !) revlog-compression-zstd (zstd !) sparserevlog store $ hg log Unknown flags to revlog are rejected >>> with open('.hg/store/00changelog.i', 'wb') as fh: ... fh.write(b'\xff\x00\xde\xad') and None $ hg log abort: unknown flags (0xff00) in version 57005 revlog 00changelog.i [50] $ cd .. Writing a simple revlog v2 works $ hg init simple $ cd simple $ touch foo $ hg -q commit -A -m initial $ hg log changeset: 0:96ee1d7354c4 tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: initial Header written as expected $ f --hexdump --bytes 4 .hg/store/00changelog.i .hg/store/00changelog.i: 0000: 00 01 de ad |....| $ f --hexdump --bytes 4 .hg/store/data/foo.i .hg/store/data/foo.i: 0000: 00 01 de ad |....|