Re: [RFC/PATCH] tag: make list exclude !<pattern>

From: Junio C Hamano <gitster@pobox.com>
Date: Feb 13, 2012, 10:23 UTC
Message-ID: <7v4nuvghfk.fsf@alter.siamese.dyndns.org>
In-Reply-To: <4F38D9D4.5000203@alum.mit.edu>

Michael Haggerty <mhagger@alum.mit.edu> writes:

Show 32 quoted lines

> On 02/13/2012 07:37 AM, Junio C Hamano wrote:
>> Michael Haggerty <mhagger@alum.mit.edu> writes:
>> 
>>> Of *course* they operate on different namespaces.  But part of the way
>>> that revisions are selected using rev-list is by *selecting or excluding
>>> refnames* from which it should crawl.
>> 
>> I am appalled if that is truly the understanding of yours, after having
>> taken more than a few patches from you to fairly core parts of Git.
>> 
>> "rev-list A ^B" does not say "include A and exclude B from which rev-list
>> should crawl" AT ALL.  We _actively_ crawl from both A and B.  It is that
>> what are reachable from B is painted in a color different from the color
>> in which we paint what are reachable from A.
>
> Please read my emails more carefully before insulting me.
> ...
> o---o---o---*  A
>      \   \
>       \   o---o  C
>        \
>         *---*  B
>
> ... vs ...
>
> *---*---*---*  A
>      \   \
>       \   o---o  C
>        \
>         *---*  B
>
> I argue that this is a useful selection.

Then why were you so against the addition of "negation" to for-each-ref?

If you want "I want histories reaching A and B", just say "rev-list A B", without adding useless "er, I do not want histories reaching C in the output, but I do not want commits reachable from C to be excluded from the output either" by mentioning C. Learn to shut your mouth and not talk about irrelevant "C" in such a case, and you will do just fine.

Especially, re-read your first message where you said that between

    git rev-list A B ^C

and

    git rev-list $(git for-each-ref A B ^C)

"consistency suggests should do the same". Should the consistency also suggest that

    git rev-list $(git rev-parse A B ^C)

do the same? That is a total bullshit that can only come from somebody who does not understand the distinction between pattern matching in refnames vs set operation over commit DAG.

Having said all that, if your argument against using "^" as negation for for-each-ref *were* with something like this from the beginning:

    git rev-list --all --exclude-refs=refs/tags/v\*

it would have been very different. I would wholeheartedly buy the consistency argument that says

    git for-each-ref --exclude-refs=refs/tags/v\*

ought to give all refs (only because for-each-ref "all" is implied) except for the tagged tips, and

    git log --all --exclude-refs=refs/tags/v\*

should be the notation to produce consistently the same result as

    git log $(git for-each-ref --format='%(objectname)' --exclude-refs=refs/tags/v\*)

but if we used "^" as negated match in for-each-ref argument, we would close the door to give such consistency to log family of commands later.

But that wasn't what you said. Why should I get accused of not guessing what you meant to say but you clearly didn't, and in addition blamed for insulting merely for pointing out the idiocy in what you said?

No. *YOU* go back and re-read your message more carefully.