[PATCH 1 of 2] histedit: add stop verb

[David Soria Parra]

Am 9/9/14, 10:32 AM, schrieb Augie Fackler:
> 
> On Sep 9, 2014, at 12:54 PM, David Soria Parra <davidsp at fb.com> wrote:
> 
>>
>>
>> Am 9/9/14, 9:35 AM, schrieb Augie Fackler:
>>>
>>> On Sep 9, 2014, at 12:34 PM, David Soria Parra <davidsp at fb.com
>>> <mailto:davidsp at fb.com>> wrote:
>>>
>>>>
>>>>
>>>> Am 9/9/14, 8:57 AM, schrieb Augie Fackler:
>>>>> On Mon, Sep 08, 2014 at 09:35:54AM -0700, David Soria Parra wrote:
>>>>>> # HG changeset patch
>>>>>> # User David Soria Parra <davidsp at fb.com <mailto:davidsp at fb.com>>
>>>>>> # Date 1409941197 -7200
>>>>>> #      Fri Sep 05 20:19:57 2014 +0200
>>>>>> # Node ID e79544cdfb81f88d782e923d96e8ad63303aec94
>>>>>> # Parent  c4b1d0db14c257e9fbb58e0f044c28f12dade3dd
>>>>>> histedit: add stop verb
>>>>>>
>>>>>> We are adding a 'stop' verb for histedit. This applies the changes
>>>>>> and drops the user into a shell after committing the changes. This
>>>>>> allows to
>>>>>> amend or modify the commit with external tooling. However, as a
>>>>>> changeset can
>>>>>> have potential children which would dissallow amending, we have to
>>>>>> recreate the
>>>>>> commit and therefore all hashes after a first stop are changing.
>>>>>
>>>>> What happens if I do 'stop' but don't make changes? Does the user get
>>>>> to retain the original, non-fussed-with hash?
>>>>>
>>>>> (I'm not 100% sure it's a showstopper if the answer is "no", but I'd
>>>>> really like the answer to be "yes".)
>>>>
>>>> The answer here is "no". When we are recreating the node, we are getting
>>>> a new hash. We would need to be able to compare afterwards if the new
>>>> node and the original node "match", consdering they have different
>>>> hashes. As far as I can tell we don't have any way to do that at the
>>>> moment, so I opted that we always recreate the node if you use stop and
>>>> have obsolence markers disabled.
>>>
>>> Could you compare the manifest node? Would that always be the same?
>>
>> Yes. But this assumes that the user didn't change just the commit
>> message or author.
> 
> 
> Hm.
> 
> Could we just only offer 'stop' if the user has obsolete enabled? Would that be sufficient for Facebook today, and not put weird edge cases into the behavior of histedit?

I don't think that will be sufficient. Obsolence markers have too much
of a perf impact these days to be enabled.