Re: [PATCH v2 03/18] ref-filter: make valid_atom as function parameter

["Оля Тележная" <olyatelezhnaya@gmail.com>]

2018-01-19 20:14 GMT+03:00 Christian Couder <christian.couder@gmail.com>:
> On Thu, Jan 18, 2018 at 7:20 AM, Оля Тележная <olyatelezhnaya@gmail.com> wrote:
>> 2018-01-18 1:39 GMT+03:00 Christian Couder <christian.couder@gmail.com>:
>>> On Wed, Jan 17, 2018 at 10:43 PM, Jeff King <peff@peff.net> wrote:
>>>> On Tue, Jan 16, 2018 at 09:55:22AM +0300, Оля Тележная wrote:
>>>>
>>>>> > IOW, the progression I'd expect in a series like this is:
>>>>> >
>>>>> >   1. Teach ref-filter.c to support everything that cat-file can do.
>>>>> >
>>>>> >   2. Convert cat-file to use ref-filter.c.
>>>>>
>>>>> I agree, I even made this and it's working fine:
>>>>> https://github.com/git/git/pull/450/commits/1b74f1047f07434dccb207534d1ad45a143e3f2b
>>>
>>> (Nit: it looks like the above link does not work any more, but it
>>> seems that you are talking about the last patch on the catfile
>>> branch.)
>>>
>>>>> But I decided not to add that to patch because I expand the
>>>>> functionality of several commands (not only cat-file and
>>>>> for-each-ref), and I need to support all new functionality in a proper
>>>>> way, make these error messages, test everything and - the hardest one
>>>>> - support many new commands for cat-file. As I understand, it is not
>>>>> possible unless we finally move to ref-filter and print results also
>>>>> there. Oh, and I also need to rewrite docs in that case. And I decided
>>>>> to apply this in another patch. But, please, say your opinion, maybe
>>>>> we could do that here in some way.
>>>>
>>>> Yeah, I agree that it will cause changes to other users of ref-filter,
>>>> and you'd need to deal with documentation and tests there. But I think
>>>> we're going to have to do those things eventually (since supporting
>>>> those extra fields everywhere is part of the point of the project). And
>>>> by doing them now, I think it can make the transition for cat-file a lot
>>>> simpler, because we never have to puzzle over this intermediate state
>>>> where only some of the atoms are valid for cat-file.
>>>
>>> I agree that you will have to deal with documentation and tests at one
>>> point and that it could be a good idea to do that now.
>>>
>>> I wonder if it is possible to add atoms one by one into ref-filter and
>>> to add tests and documentation at the same time, instead of merging
>>> cat-file atoms with ref-filter atoms in one big step.
>>>
>>> When all the cat-file atoms have been added to ref-filter's
>>> valid_atom, maybe you could add ref-filter's atoms to cat-file's
>>> valid_cat_file_atom one by one and add tests and documentation at the
>>> same time.
>>>
>>> And then when ref-filter's valid_atom and cat-file's
>>> valid_cat_file_atom are identical you can remove cat-file's
>>> valid_cat_file_atom and maybe after that rename "ref-filter" to
>>> "format".
>>
>> I think it's important to finish migrating process at first. I mean,
>> now we are preparing and collecting everything in ref-filter, but we
>> make resulting string and print still in cat-file. And I am not sure,
>> but maybe it will not be possible to start using new atoms in cat-file
>> while some part of logic still differs.
>
> Ok, you can finish the migration process then.
>
>> And another thoughts here - we were thinking about creating format.h
>> but decided not to move forward with it, and now we are suffering
>> because of it. Can I create it right now or the history of commits
>> would be too dirty because of it?
>
> It would also make it difficult to refactor your patch series if there
> is a big move or renaming in the middle.
>
>> Also, do you mean just renaming of
>> ref-filter? I was thinking that I need to put formatting-related logic
>> to another file and leave all other stuff in ref-filter.
>
> Yeah, you can do both a move and a renaming.

Thanks for a response! That thought is not clear enough for me. Do you
want me to split ref-filter into 2 files (one is for formatting only
called format and other one is for anything else still called
ref-filter) - here is a second question by the way, do I need to
create only format.h (and leave all realizations in ref-filter.c), or
I also need to create format.c. Or, just to rename ref-filter into
format and that's all.

>
>> Anyway, your suggested steps looks good, and I am planning to
>> implement them later.
>
> Ok.
>
>> Let's discuss, what behavior we are waiting for
>> when atom seems useless for the command. Die or ignore?
>
> We could alternatively just emit a warning, but it looks like there
> are a lot of die() calls already in ref-filter.c, so I would suggest
> die().
>
>> And, which
>> atoms are useless (as I understand, "rest" and "deltabase" from
>> cat-file are useless for all ref-filter users, so the question is
>> about - am I right in it, and about ref-filter atoms for cat-file).
>
> For now and I think until the migration process is finished, you could
> just die() in case of any atom not already supported by the command.
>
>> I have never written any tests and docs for Git, I will try to explore
>> by myself how to do that, but if you have any special links/materials
>> about it - please send them to me :)
>
> I think that looking at the existing documentation and tests is
> probably the best way to learn about it.