[Python-Dev] Workflow proposal

[John Arbash Meinel]

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On 3/23/2011 1:23 PM, Dirkjan Ochtman wrote:
> On Wed, Mar 23, 2011 at 12:39, John Arbash Meinel
> <john at arbash-meinel.com> wrote:
>> Just as an aside, and I might be wrong. But reading through what strip
>> does, (and from my knowledge of the disk layout) it can't actually be
>> atomic. So if you kill it at the wrong time, it will have corrupted your
>> repository.
>>
>> At least, that is from what I can tell. Which is that it has to rewrite
>> each file history to omit the revisions you are stripping, and then
>> rewrite the revision history to do the same. It would be possible to be
>> 'stable' if you wrote a write-ahead-log and did all the work on the
>> side, and then any client that tries to read or write to the repository
>> finishes up the steps. But the individual file histories refer to the
>> global revision history (by index), so you don't have a 'top-down' view
>> that makes it all atomic by changing the top level object to point to
>> the new lower level objects.
> 
> The reason that shouldn't happen is the ordering. If we strip the
> changelog first (what you call the global revision history), other
> clients won't be able to "find" the any file-level revisions only
> referenced by the revision just stripped, so it should be atomic.
> 
> Cheers,
> 
> Dirkjan

http://mercurial.selenic.com/wiki/Strip

Thats only true if you are stripping only from the top. According to the
strip page, you also might re-order the numbers.

Also, even with stripping the changelog first, it still leaves you with
data in your repo that is going to suddenly think it is associated with
the *next* commit you do. (So I make a change to 'foo.txt' commit it,
then strip, the next commit I only change 'bar.txt'. If the strip was
canceled 'hg log foo.txt' would include the latest revision as modifying
foo.txt)

John
=:->
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