Re: [PATCH v10 0/9] submodule inline diff format

[Stefan Beller <sbeller@google.com>]

On Thu, Aug 25, 2016 at 3:46 PM, Jacob Keller <jacob.keller@gmail.com> wrote:
> On Thu, Aug 25, 2016 at 3:38 PM, Junio C Hamano <gitster@pobox.com> wrote:
>> Jacob Keller <jacob.keller@gmail.com> writes:
>>
>>> So we should support the gitlink to a repository stored at <path>
>>> without stuff inside the .git/modules, and we should support submodule
>>> gitlinks with a proper .gitmodules setup. I don't think we should
>>> die() but we should error properly so I will introduce a _gently()
>>> variant of these functions, and die properly in the regular flow.
>>
>> Because "git diff [--cached] [<tree-ish>]" in the top-level is
>> driven by a gitlink in the index, immediately after adding a new
>> submodule to the index but before describing it in .gitmodules you
>> might not have a name (and you know in that case the path will
>> become the name when adding it to .gitmodules).  Also a gitlink in
>> the index may correspond to a submodule the user of the top-level is
>> not interested in, so there may not be anything in .git/modules/
>> that corresponds to it.  In these cases, I suspect that you do not
>> want to die, but you can just tell the user "I do not have enough
>> information to tell you a useful story yet".
>>
>
> Right. submodule_from_path() fails to find a config. I don't think
> die() is right here, because there is no easy way to make this into a
> gently() variant.... I can still do it if we think a die() is
> worthwhile otherwise for the other callers of do_submodule_path...
>
> However, I think the safest thing is to just:
>
> a) read_gitfile on <path>/.git
> b) if read_gitfile succeeds, use it's contents, otherwise use
> <path>/.git for next steps
> c) check if the resulting file is a git directory, we're fine.. we
> found a gitdir, so stop.
> d) otherwise,  empty the buffer, then lookup submodules
> e) when submodules lookup succeeds.. see if we found a name. If so, use that.

When the submodules lookup succeeds, we can assert the name exists.
There is currently only one way the lookup is populated, and that is
lookup_or_create_by_name in submodule-config.c:182, which fills in
the name all the time.

> f) if we didn't just exit with an empty buffer.
>
> That empty buffer *should* trigger  revision error codes since it
> won't point to any valid path and it also triggers the regular error
> code in add_submodule_odb so it handles that with showing not
> initizlied.
>
> This method is less work then re-implementing a _gently() variant for
> all of these functions.
>
> Stefan, does this make sense and seem reasonable?

Sounds reasonable to me.

Thanks for working on this!
Stefan