On Mon, Dec 12, 2016 at 2:17 AM, Pierre-Yves David <
pierre-yves.da...@ens-lyon.org> wrote:
>
>
> On 11/25/2016 04:28 AM, Gregory Szorc wrote:
>
>> # HG changeset patch
>> # User Gregory Szorc <gregory.sz...@gmail.com>
>> # Date 1480033449 28800
>> # Thu Nov 24 16:24:09 2016 -0800
>> # Node ID 4fffbdc2bca22e666482b55562c0e592c8a68027
>> # Parent c60995fce14b0e34bd1416dab3712a6c33bb29bb
>> debugcommands: stub for debugupgraderepo command
>>
>> Currently, if Mercurial introduces a new repository/store feature or
>> changes behavior of an existing feature, users must perform an
>> `hg clone` to create a new repository with hopefully the
>> correct/optimal settings. Unfortunately, even `hg clone` may not
>> give the correct results. For example, if you do a local `hg clone`,
>> you may get hardlinks to revlog files that inherit the old state.
>> If you `hg clone` from a remote or `hg clone --pull`, changegroup
>> application may bypass some optimization, such as converting to
>> generaldelta.
>>
>> Optimizing a repository is harder than it seems and requires more
>> than a simple `hg` command invocation.
>>
>> This commit starts the process of changing that. We introduce
>> `hg debugupgraderepo`, a command that performs an in-place upgrade
>> of a repository to use new, optimal features. The command is just
>> a stub right now. Features will be added in subsequent commits.
>>
>
> I like the idea of this commit, this should probably be the first one in
> the stack. The revlog cloning feature can be delayed later in the stack
> until we actually start performing upgrade.
>
> This commit does foreshadow some of the behavior of the new command,
>> notably that it doesn't do anything by default and that it takes
>> arguments that influence what actions it performs. These will be
>> explained more in subsequent commits.
>>
>> diff --git a/mercurial/debugcommands.py b/mercurial/debugcommands.py
>> --- a/mercurial/debugcommands.py
>> +++ b/mercurial/debugcommands.py
>> @@ -849,3 +849,28 @@ def debugdeltachain(ui, repo, file_=None
>> extradist=extradist, extraratio=extraratio)
>>
>> fm.end()
>> +
>> +@command('debugupgraderepo', [
>> + ('o', 'optimize', [], _('extra optimization to perform'), _('NAME')),
>> + ('', 'run', False, _('performs an upgrade')),
>>
>
> We should drop these option from the command until we actually use them
> this will allow to discuss them with their actual behavior.
>
> +])
>> +def debugupgraderepo(ui, repo, run=False, optimize=None):
>> + """upgrade a repository to use different features
>> +
>> + If no arguments are specified, the repository is evaluated for
>> upgrade
>> + and a list of problems and potential optimizations is printed.
>> +
>> + With ``--run``, a repository upgrade is performed. Behavior of the
>> upgrade
>> + can be influenced via additional arguments. More details will be
>> provided
>> + by the command output when run without ``--run``.
>>
>
> (I would also delayed the help about --run until we actually run something)
>
> +
>> + During the upgrade, the repository will be locked and no writes will
>> be
>> + allowed.
>> +
>> + At the end of the upgrade, the repository may not be readable while
>> new
>> + repository data is swapped in. This window will be as long as it
>> takes to
>> + rename some directories inside the ``.hg`` directory. On most
>> machines, this
>> + should complete almost instantaneously and the chances of a consumer
>> being
>> + unable to access the repository should be low.
>>
>
> (I would also delay that doc until we actually behave that way)
> I know it would bot solve "everything" but we discussed the option of
> having a "repositorybeingupgraded" (or similar) in .hg/required to reduce
> the change for a reader to access the repository at that time.
>
I added all this code and documentation to foreshadow the feature so a
reviewer isn't guessing where things are going. It also cuts down on the
amount of patches and/or churn in future patches, making code review
easier, IMO. I think it is busy work to change it at this stage. But if you
insist, I will.
>
> + """
>> + raise error.Abort(_('not yet implemented'))
>> diff --git a/tests/test-completion.t b/tests/test-completion.t
>> --- a/tests/test-completion.t
>> +++ b/tests/test-completion.t
>> @@ -109,6 +109,7 @@ Show debug commands if there are no othe
>> debugsub
>> debugsuccessorssets
>> debugtemplate
>> + debugupgraderepo
>> debugwalk
>> debugwireargs
>>
>> @@ -274,6 +275,7 @@ Show all commands + options
>> debugsub: rev
>> debugsuccessorssets:
>> debugtemplate: rev, define
>> + debugupgraderepo: optimize, run
>> debugwalk: include, exclude
>> debugwireargs: three, four, five, ssh, remotecmd, insecure
>> files: rev, print0, include, exclude, template, subrepos
>> diff --git a/tests/test-help.t b/tests/test-help.t
>> --- a/tests/test-help.t
>> +++ b/tests/test-help.t
>> @@ -916,6 +916,8 @@ Test list of internal help commands
>> show set of successors for revision
>> debugtemplate
>> parse and apply a template
>> + debugupgraderepo
>> + upgrade a repository to use different features
>> debugwalk show how files match on given patterns
>> debugwireargs
>> (no help text available)
>> diff --git a/tests/test-upgrade-repo.t b/tests/test-upgrade-repo.t
>> new file mode 100644
>> --- /dev/null
>> +++ b/tests/test-upgrade-repo.t
>> @@ -0,0 +1,5 @@
>> + $ hg init empty
>> + $ cd empty
>> + $ hg debugupgraderepo
>> + abort: not yet implemented
>> + [255]
>> _______________________________________________
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>> Mercurial-devel@mercurial-scm.org
>> https://www.mercurial-scm.org/mailman/listinfo/mercurial-devel
>>
>>
> --
> Pierre-Yves David
>
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