Re: [Gnu-arch-users] Re: Are pristine trees really dead?

[Aaron Bentley]

Tom Lord wrote:

>    > When a greedy library wasn't the first
>    > library, find_or_make_local_copy ignored it.
>
>    > With my changes, all greedy libraries are considered, and the
>    > greedy to be used is chosen by the criteria library_add_choice
>    > uses: greedies that contain the same version are preferred over
>    > greedies that contain the same branch, which are preferred over
>    > treedies that contain the same archive, but if there aren't any
>    > we use the first-listed greedy.
>
>    > So if you have one or more greedies, no matter where they appear
>    > in the path, tla changes, undo, and others will no longer
>    > produce pristines.
>
> In other words, this inverts "precedence" and "greediness" in making
> the library choice.  It used to be that the same-version-or-branch-or
> ... library was picked first and then, among the qualifying libraries,
> the first listed greedy one or if none of those is greedy then the
> first listed.   As a result, if tla wanted to auto add a revision but
> the rule picked a non-greedy library, even if there was a greedy
> library available, the auto-add wouldn't happen.
>
> Now you're saying: "if _any_ greedy library is on the path then a
> greedy library will be used --- then the first one listed with best
> precedence".
>  
This in the context of auto-adds, so it was never permissible to add to 
a non-greedy library.  But previously, only the first-listed library was 
a candidate for auto-adding.  Now all greedy libraries are candidates 
for auto-adding.

The specific greedy library is selected by applying normal precedence to 
the list of greedy libraries.

> Your proposed change makes better sense then the rule that's there.
>
>
>
>    > The practical upshot of this is that you can use your greedy to
>    > track head revisions, while keeping a milestone revisions
>    > (e.g. branch points) in a non-greedy that you can manipulate
>    > with library-add/remove (and no need to specify which library on
>    > the commandline).
>
> Except that I don't understand that last parenthetical.  If I want to
> add a revision to the non-greedy milestone library I need to name that
> library explicitly on the library-add command line, right?
I haven't changed user-adds at all*.  So if a non-greedy library is a 
better candidate, it will be selected.  Path-order is used as a tie 
breaker, so if the libraries are equally qualified in every other 
respect, the first library (i.e. the non-greedy) will be used.

>   That's
> fine, IMO, but the parenthetical comment suggests it isn't true so
> perhaps I misunderstand what you mean.
>  
Is that clearer?

Aaron

*Except possibly by accident.