Mercurial > hg-stable
changeset 42136:10a6725dca6e
compression: introduce an official `zstd-revlog` requirement
This requirement supersedes `exp-compression-zstd`. However, we keep support for
the old requirement.
Strictly speaking, we do not need to add a new requirement, there are no logic
change making "new" repo incompatible with mercurial client using a version
that support `exp-compression-zstd`.
The choice to introduce a new requirement is motivated by the following:
* The previous requirement was explicitly "experimental". Using it by default
could confuse users.
* adding support for a hypothetical third compression engine will requires new
code, and will comes with its own requirement tool.
* We won't use it as the default for a while since I do not think we support
zstd on all platform. I can imagine we'll gain another (unrelated but on my
default) requirement by the time we turn this zstd by default.
| author | Pierre-Yves David <pierre-yves.david@octobus.net> |
|---|---|
| date | Wed, 27 Mar 2019 18:27:03 +0100 |
| parents | b970fece153d |
| children | d086ba387ae8 |
| files | mercurial/localrepo.py mercurial/upgrade.py tests/test-repo-compengines.t |
| diffstat | 3 files changed, 22 insertions(+), 7 deletions(-) [+] |
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--- a/mercurial/localrepo.py Tue Apr 16 15:10:16 2019 +0200 +++ b/mercurial/localrepo.py Wed Mar 27 18:27:03 2019 +0100 @@ -645,6 +645,8 @@ engine = util.compengines[name] if engine.available() and engine.revlogheader(): supported.add(b'exp-compression-%s' % name) + if engine.name() == 'zstd': + supported.add(b'revlog-compression-zstd') return supported @@ -794,8 +796,13 @@ options[b'maxchainlen'] = maxchainlen for r in requirements: - if r.startswith(b'exp-compression-'): - options[b'compengine'] = r[len(b'exp-compression-'):] + # we allow multiple compression engine requirement to co-exist because + # strickly speaking, revlog seems to support mixed compression style. + # + # The compression used for new entries will be "the last one" + prefix = r.startswith + if prefix('revlog-compression-') or prefix('exp-compression-'): + options[b'compengine'] = r.split('-', 2)[2] options[b'zlib.level'] = ui.configint(b'storage', b'revlog.zlib.level') if options[b'zlib.level'] is not None: @@ -2943,7 +2950,9 @@ 'compression engines')) # zlib is the historical default and doesn't need an explicit requirement. - if compengine != 'zlib': + elif compengine == 'zstd': + requirements.add('revlog-compression-zstd') + elif compengine != 'zlib': requirements.add('exp-compression-%s' % compengine) if scmutil.gdinitconfig(ui):
--- a/mercurial/upgrade.py Tue Apr 16 15:10:16 2019 +0200 +++ b/mercurial/upgrade.py Wed Mar 27 18:27:03 2019 +0100 @@ -325,10 +325,16 @@ @classmethod def fromrepo(cls, repo): + # we allow multiple compression engine requirement to co-exist because + # strickly speaking, revlog seems to support mixed compression style. + # + # The compression used for new entries will be "the last one" + compression = 'zlib' for req in repo.requirements: - if req.startswith('exp-compression-'): - return req.split('-', 2)[2] - return 'zlib' + prefix = req.startswith + if prefix('revlog-compression-') or prefix('exp-compression-'): + compression = req.split('-', 2)[2] + return compression @classmethod def fromconfig(cls, repo):