Re: [PATCH v5 2/3] diff: add --diff-line-prefix option for passing in a prefix

> Jacob Keller <jacob.keller@gmail.com> writes:
>
>> On Fri, Aug 12, 2016 at 2:58 PM, Junio C Hamano <gitster@pobox.com> wrote:
>>> On Fri, Aug 12, 2016 at 2:43 PM, Jacob Keller <jacob.keller@gmail.com> wrote:
>>>> Ok so the big problem here is that unlike with diff which has support
>>>> for line-prefixes already due to needing it for graph mode, I can't
>>>> figure out where to get the prefix added for log output.
>>>
>>> Doesn't the --graph mode show the graph lines already? I think most
>>> if not all of that processing happens inside log-tree.c::show_log().
>>
>> Yes but the problem is how to get this additional prefix to be displayed for
>>
>> (a) non graph mode
>> (b) for graph mode but display the prefix before the graph prefix
>>
>> It doesn't seem straight forward, and I haven't figured out how the
>> graph code already works.
>
> Because you only need "diff --line-prefix" to work while leaving
> "log --line-prefix" broken for the purpose of your immediate purpose
> to update "diff/log [--graph and other options] --submodule=<type>"
> to show "diff A B" in the submodule, I think it is OK to leave it
> broken, as long as it is clearly documented that "--line-prefix"
> should also apply to the log message part but the current code
> doesn't.  Eventually, when somebody wants to add a new <type> that
> runs "log -p A..B" instead of "diff A B" in submodules and wants to
> make it interact well with "log --graph" at the superproject level,
> they need to fix the breakage you leave behind.  That would be much
> better than "because I cannot figure out how to prefix on the log
> part, I'll name this --diff-line-prefix", which will force us to
> support that half-baked option forever while having to add a proper
> "--line-prefix" eventually anyway.