[PATCH 2 of 2] commands: allow debugobsolete to delete arbitrary obsmarkers

[Kostia Balytskyi]

On 4/1/16, 7:31 PM, "Pierre-Yves David" <pierre-yves.david at ens-lyon.org> wrote:

>
>
>On 04/01/2016 08:56 AM, Kostia Balytskyi wrote:
>> # HG changeset patch
>> # User Kostia Balytskyi <ikostia at fb.com>
>> # Date 1459525644 25200
>> #      Fri Apr 01 08:47:24 2016 -0700
>> # Node ID ff46f27e8fca7b726cc042eb745e54a3bc9dbe39
>> # Parent  d4fc1ec31c6666d85eb2e8c174f6c231546ad8fd
>> commands: allow debugobsolete to delete arbitrary obsmarkers
>>
>> Sample usage is:
>>    '$ hg debugobsolete --delete 0 5'
>>
>> This is a debug feature that will help people working on evolution and
>> obsolescense.
>>
>> diff --git a/mercurial/commands.py b/mercurial/commands.py
>> --- a/mercurial/commands.py
>> +++ b/mercurial/commands.py
>> @@ -3046,6 +3046,7 @@ def debuglocks(ui, repo, **opts):
>>             _('record parent information for the precursor')),
>>            ('r', 'rev', [], _('display markers relevant to REV')),
>>            ('', 'index', False, _('display index of the marker')),
>> +         ('', 'delete', [], _('delete markers specified by indices')),
>>           ] + commitopts2,
>>            _('[OBSOLETED [REPLACEMENT ...]]'))
>>   def debugobsolete(ui, repo, precursor=None, *successors, **opts):
>> @@ -3066,6 +3067,16 @@ def debugobsolete(ui, repo, precursor=No
>>               raise error.Abort('changeset references must be full hexadecimal '
>>                                'node identifiers')
>>
>> +    if opts.get('delete'):
>> +        try:
>> +            indices = [int(v) for v in opts.get('delete')]
>> +        except ValueError:
>> +            raise error.Abort(_('invalid index value'),
>> +                              hint=_('use integers fro indices'))
>> +        n = repo.obsstore.delete(indices)
>
>We'll want some locking around this to prevent other process reading the 
>repository to misbehave.
>
>> +        ui.write(_('Deleted %i obsolescense markers\n') % n)
>> +        return
>> +
>>       if precursor is not None:
>>           if opts['rev']:
>>               raise error.Abort('cannot select revision when creating marker')
>> diff --git a/mercurial/obsolete.py b/mercurial/obsolete.py
>> --- a/mercurial/obsolete.py
>> +++ b/mercurial/obsolete.py
>> @@ -633,6 +633,30 @@ class obsstore(object):
>>           transaction.hookargs['new_obsmarkers'] = str(previous + len(new))
>>           return len(new)
>>
>> +    def delete(self, indices):
>> +        """Delete some obsmarkers from store and return the number of them
>> +
>> +        Indices is a list of ints which are the indices
>> +        of the markers to be deleted."""
>> +        if not indices:
>> +            # we don't want to rewrite the obsstore with the same content
>> +            return
>> +
>> +        left = []
>> +        current = self._all
>> +        n = 0
>> +        for i, m in enumerate(current):
>> +            if i in indices:
>> +                n += 1
>> +                continue
>> +            left.append(m)
>> +
>> +        newobsstore = self.svfs('obsstore', 'w', atomictemp=True)
>> +        for bytes in encodemarkers(left, True, self._version):
>> +            newobsstore.write(bytes)
>> +        newobsstore.close()
>> +        return n
>> +
>
>We probably want to have this somewhat collaborating with the 
>transaction, like mercurial.repair.strip do. At least we want to ensure 
>we are not in a transaction before butchering the obstore.

Why do we want transaction if we're writing to the atomictemp file? AFAIK,
it will write the new stuff into a temporary file and atomically rename it
when we call close. Why isn't it good enough?

>
>(and that we are locked)
>
>>       def mergemarkers(self, transaction, data):
>>           """merge a binary stream of markers inside the obsstore
>
>
>-- 
>Pierre-Yves David