Re: [BUG] Possible bug in `remote set-url --add --push`

[Michael J Gruber <git@drmicha.warpmail.net>]

Junio C Hamano venit, vidit, dixit 15.01.2013 16:53:
> Michael J Gruber <git@drmicha.warpmail.net> writes:
> 
>> Also there is a conceptual confusion: pushurl is meant to push to the
>> same repo using a different url, e.g. something authenticated
>> (https/ssh) for push and something faster/easier for fetch.
> 
> That is not necessarily true, depending on the definition of your
> "same".  Having multiple URLs/PushURLs that refer to physically
> different locations, as long as "git push there" immediately
> followed by "git fetch here" should work with the repositories that
> are conceptually equivalent, is a supported mode of operation. In

That is my definition of "same", in the sense of "object-and-ref-same"
when "in-sync" (at least regarding all pushed refs; there may be more
there).

> fact, they being physically different _was_ the original motivation
> of the feature. See 755225d (git builtin "push", 2006-04-29).

I thought it was about unauthenticated git-protocol vs. git+ssh but was
wrong.

> The definition of the "immediate" above also depends on your use; it
> could be tens of minutes (you may be fetching from git.k.org that
> can be reached from the general public, which may be a cname for
> multiple machines mirroring a single master.k.org that k.org account
> holders push to, and there may be propagation delays).  In such a
> scenario, your URL may point at the public git.k.org, pushURL may
> point at master.k.org, and you may have other pushURLs that point at
> other places you use as back-up locations (e.g. git.or.cz or
> github.com).

Yes. That is also why we fetch from one fetch URL only, because we
assume they point at the "same" repo and don't need to check.

> As long as you _mean_ to maintain their contents the same, you can
> call them conceptually "the same repo" and your statement becomes
> true.
> 
>> It never was meant to push to several repos.
> 
> This is false.  It _was_ designed to be used that way from day one.

It is very true with me definition of "same" ;)

> (I am not saying using it in other ways is an abuse---I am merely
> saying that pushing to multiple physically different repositories is
> within its scope).
> 
>> That being said, I don't mind changing the behaviour of set-url.
> 
> I do not think we want to change the behaviour of set-url.  What
> needs to be fixed is the output from "remote -v".  It should:
> 
>  * When there is no pushURL but there is a URL, then show it as
>    (fetch/push), and you are done;
> 
>  * When there is one or more pushURLs and a URL, then show the URL
>    as (fetch), and show pushURLs as (push), and you are done;
> 
>  * When there are more than one URLs, and there is no pushURL, then
>    show the first URL as (fetch/push), and the remainder in a
>    notation that says it is used only for push, but it shouldn't be
>    the same "(push)"; the user has to be able to distinguish it from
>    the pushURLs in a repository that also has URLs.

Maybe "(fetch fallback/push)" if we do use it as a fallback? If we don't
we probably should?

>  * When there are more than one URLs, and there are one or more
>    pushURLs, then show the first URL as (fetch), the other URLs
>    as (unused), and the pushURLs as (push).
> 
> Strictly speaking, the last one could be a misconfiguration.  If you
> have:
> 
> 	[remote "origin"]
>         	url = one
>                 url = two
>                 pushurl = three
>                 pushurl = four
> 
> then your "git fetch" will go to one, and "git push" will go to
> three and four, and two is never used.

Do we fall back to two if one is unavailable? In any case, people may
use a configuration like that to keep track of mirrors and shuffle
around the fetch lines (rather than commenting/uncommenting) when one
goes offline.

> It should also be stressed that the third one a supported
> configuration.  With
> 
> 	[remote "origin"]
>         	url = one
>                 url = two
> 
> your "git fetch" goes to one, and your "git push" will go to one and
> two.  This is the originally intended use case of 755225d.  It is to
> push to and fetch from master.k.org (think of "one" above) and in
> addition to push to backup.github.com ("two").

Michael