Re: Remotes order in "git remote update"

[Junio C Hamano <gitster@pobox.com>]

Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

> On Mon, 10 Mar 2008, Samuel Tardieu wrote:
>
>> On  9/03, Johannes Schindelin wrote:
>> 
>> | Well, technically this is a regression.
>> | 
>> | If you really want to order your remotes, why not add something like
>> | 
>> | [remotes]
>> | 	default = my-first-remote my-second-remote [...]
>> | 
>> | to the config?  That is what the (recently fixed in builtin-remote) 
>> | remote groups are for...
>> 
>> I could do that, but it means that if I add a new remote, it won't enter 
>> the default group by itself since I defined it explicitely. I think 
>> respecting the order given in the .git/config file when not using a 
>> group doesn't hurt and may help.
>
> Well, since the builtin remote does that, I do not see a reason to change 
> it ;-)  However, I do not see a reason to guarantee that, either.

I think it is a reasonable expectation that, if you have these in the
configuration file (not limited to "remotes" but for a random "a"):

	[a "foo"]
        	x = "frotz"
                x = "xyzzy"
	[a "bar"]
        	x = "nitfol"
                x = "rezrov"

something that _iterates_ over a.*.* would see them in the order of
appearance (foo.frotz, foo.xyzzy, bar.nitfol and then bar.rezrov).

If you need both iterable and also quick lookup (e.g. when there can be
thousands of "foo" and "bar" for a particular "a" and it is common to ask
for "a.$name.x" for random $name), the config reader for "a" needs to
have an implementation that is better than just a naive linear list.
Maybe it can use a hashed table whose entry records the appearance order
in the configuration file, expecting that a look-up is far more common
operation than enumeration, and when somebody asks you to enumerate, you
can create a sorted list on-demand and iterate on that.  The
implementation would be different depending on the expected usage pattern,
but I do not see much to gain for us by reserving the right to enumerate
things in a random order.