Re: [PATCH 2/2] revision: implement --show-linear-break for --graph

[Kyle Marek <kmarek@pdinc.us>]

On 1/17/21 9:09 PM, Junio C Hamano wrote:
> Junio C Hamano<gitster@pobox.com>  writes:
>
>> In other words, revs->break_revision_mark is left NULL unless
>> --show-linear-break is given.
>>
>>> @@ -4192,8 +4192,8 @@ const char *get_revision_mark(const struct rev_info *revs, const struct commit *
>>>   		else
>>>   			return ">";
>>>   	} else if (revs->graph) {
>>> -		if (!commit->parents)
>>> -			return "#";
>>> +		if (revs->break_revision_mark && !commit->parents)
>>> +			return revs->break_revision_mark;
>> And that causes this to break.  Now "--graph" alone won't show '#'
>> for the root commits, despite that is what [1/2] wanted to do.
>>
>> Here is a fix-up, plus some minimum tests.
> Having said all that, I do not mind if the new markings were
> activated only when --show-linear-break option (or a separate new
> option) is given.  But if that is where we want to go, your [1/2]
> that uses the new markings unconditionally is a regression.
>
> A better organization, if we wanted to have multiple and smaller
> steps than a single whole thing, would be:
>
>   [1/2] Introduce a new "--mark-root-commits" option, or abuse the
>         existing "--show-linear-break" option, and change "*<>"
>         marking used for commits to "#LR" (or whatever appropriate)
>         when the option is in effect.  Document the behaviour and add
>         tests.
>
>   [2/2] Introduce "--show-linear-break=<custom-value>" option.
>         Document the behaviour and add tests.
>
> If you apply [1/2] and [2/2] with the earlier fixes I sent, you'll
> see many fallouts from existing tests, as the representation of the
> root commit is changed unconditionally.  We view breakages of tests
> as a rough estimate of how badly end-user scripts could break, and
> the picture was not very pretty.  And that is why I am suggesting
> the above "only do the new markings when asked, not unconditionally"
> approach.

Sorry. I didn't make this clear. It is not an accident that patch 1 
denotes root commits unconditionally and patch 2 makes it optional. I 
present two choices. If we prefer to unconditionally denote root 
commits, patch 2 may be left out, otherwise, patch 1 should be squashed 
away.

I didn't have an opinion towards either option, but you make a good 
point about end-user scripts.

> I still am skeptical that spending 3 more letters to denote roots is
> worth it, though.

Me too, but I think a user-defined mark needs to be a string to support 
Unicode characters.

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- Kyle Marek                        PD Inc.http://www.pdinc.us  -
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