[Nix-dev] Hydra, nix-prefetch-git, and TopGit

[Marc Weber]

It should be sufficient to checkout the branch you want. Its not
important whether the branch is a topic branch or not unless you want tg
update to work. However I don't think that Hydra should run tg update.
It should be you doing this manually pushing the result somewhere (?)

details:

TopGit topic branches have an additional refs/top-bases/$NAME
branch marking the commit against which to diff when exporting a patch.
You can think of it being the "merge" of all dependencies listed in .topdeps

--populate adds local branches for all branches because those local
branches are usually referred to in .topdeps files. You could change
this and replace "dep" by "origin/dep" instead - however this would
require all users to use the same remote location name.
So without --populate you only miss the ability to run tg update
successfully AFAIK.

So if Hydra should run tg update then you have to use --populate.
Don't think its a good idea doing so in a builder though.

Marc Weber