revlog-compression: update the config to be a list
format.revlog-compression is now a list of engine, the first supported one is to
be used. Doing this have several benefits:
1) this is fully backward compatible, config using a single entry will be read
as a single item list, not changing any behavior.
2) This open the way to use zstd by default without impacting platform were it
is not available. This will be done in a later changesets.
Using zstd provide a significant performance boost explained in : bb271ec2fbfb.
However zstd is not available in some cases, A notable example is the `--pure`
version of Mercurial which doesn't come with zstd support.
Differential Revision: https://phab.mercurial-scm.org/D8148
--- a/mercurial/configitems.py Wed Feb 19 13:39:00 2020 +0530
+++ b/mercurial/configitems.py Wed Feb 19 17:30:04 2020 +0100
@@ -759,7 +759,7 @@
coreconfigitem(
b'format',
b'revlog-compression',
- default=b'zlib',
+ default=lambda: [b'zlib'],
alias=[(b'experimental', b'format.compression')],
)
coreconfigitem(
--- a/mercurial/helptext/config.txt Wed Feb 19 13:39:00 2020 +0530
+++ b/mercurial/helptext/config.txt Wed Feb 19 17:30:04 2020 +0100
@@ -888,7 +888,8 @@
Compression algorithm used by revlog. Supported values are `zlib` and
`zstd`. The `zlib` engine is the historical default of Mercurial. `zstd` is
a newer format that is usually a net win over `zlib`, operating faster at
- better compression rates. Use `zstd` to reduce CPU usage.
+ better compression rates. Use `zstd` to reduce CPU usage. Multiple values
+ can be specified, the first available one will be used.
On some systems, the Mercurial installation may lack `zstd` support.
--- a/mercurial/localrepo.py Wed Feb 19 13:39:00 2020 +0530
+++ b/mercurial/localrepo.py Wed Feb 19 17:30:04 2020 +0100
@@ -3578,14 +3578,17 @@
if ui.configbool(b'format', b'dotencode'):
requirements.add(b'dotencode')
- compengine = ui.config(b'format', b'revlog-compression')
- if compengine not in util.compengines:
+ compengines = ui.configlist(b'format', b'revlog-compression')
+ for compengine in compengines:
+ if compengine in util.compengines:
+ break
+ else:
raise error.Abort(
_(
- b'compression engine %s defined by '
+ b'compression engines %s defined by '
b'format.revlog-compression not available'
)
- % compengine,
+ % b', '.join(b'"%s"' % e for e in compengines),
hint=_(
b'run "hg debuginstall" to list available '
b'compression engines'
@@ -3593,7 +3596,7 @@
)
# zlib is the historical default and doesn't need an explicit requirement.
- elif compengine == b'zstd':
+ if compengine == b'zstd':
requirements.add(b'revlog-compression-zstd')
elif compengine != b'zlib':
requirements.add(b'exp-compression-%s' % compengine)
--- a/mercurial/upgrade.py Wed Feb 19 13:39:00 2020 +0530
+++ b/mercurial/upgrade.py Wed Feb 19 17:30:04 2020 +0100
@@ -449,7 +449,14 @@
@classmethod
def fromconfig(cls, repo):
- return repo.ui.config(b'format', b'revlog-compression')
+ compengines = repo.ui.configlist(b'format', b'revlog-compression')
+ # return the first valid value as the selection code would do
+ for comp in compengines:
+ if comp in util.compengines:
+ return comp
+
+ # no valide compression found lets display it all for clarity
+ return b','.join(compengines)
@registerformatvariant
--- a/tests/test-repo-compengines.t Wed Feb 19 13:39:00 2020 +0530
+++ b/tests/test-repo-compengines.t Wed Feb 19 17:30:04 2020 +0100
@@ -22,10 +22,15 @@
Unknown compression engine to format.compression aborts
$ hg --config format.revlog-compression=unknown init unknown
- abort: compression engine unknown defined by format.revlog-compression not available
+ abort: compression engines "unknown" defined by format.revlog-compression not available
(run "hg debuginstall" to list available compression engines)
[255]
+unknown compression engine in a list with known one works fine
+
+ $ hg --config format.revlog-compression=zlib,unknown init zlib-before-unknow
+ $ hg --config format.revlog-compression=unknown,zlib init unknown-before-zlib
+
A requirement specifying an unknown compression engine results in bail
$ hg init unknownrequirement