Jakub wrote: > I think the problem with `--reference` is that it does not > setup backreferences to prevent gc removing borrowed objects; > which is a hard problem to solve, except for limited cases... > like git-worktree. Right. And instead of solving the reference problem, I'd rather solve the worktree problem as I think it yields more? > >> So I think the current workflow for submodules >> may need some redesign anyway as the submodule >> commands were designed with a strict "one working >> tree only" assumption. >> >> Submodule URLs are stored in 3 places: >> A) In the .gitmodules file of the superproject >> B) In the option submodule.<name>.URL in the superproject >> C) In the remote.origin.URL in the submodule >> >> A) is a recommendation from the superproject to make life >> of downstream easier to find and setup the whole thing. >> You can ignore that if you want, though generally a caring >> upstream provides good URLs here. > > Also, this URL might have change if the repository moves > to other server; even when checking out ancient version > we usually want to use current URL, not the one in currently > checked-out .gitmodules file. Right. > >> C) is where we actually fetch from (and hope it has all >> the sha1s that are recorded as gitlinks in the superproject) > > Is it? Or is it only the case if you do `git fetch` or > equivalent from within inside of submodule? You can fetch > updates using `git submodule ...` from supermodule, isn't it? > But I might be wrong here. If you call `submodule update` in the superproject it actually just does a `(cd $submodule && git fetch)`. And in the submodule we have a .git file pointing to the superprojects ".git/modules/<name>/" which is a full blown git dir, i.e. it has its own config, HEAD etc. > > Also: if .git file is gitfile link, do submodule even has > it's own configuration file? Yes they do. > >> >> B) seems like a hack to enable the workflow as below: > > It has overloaded meaning, being used both for current URL > of submodule as seen in supermodule, AND that submodule > is checked out / needs to be checked out in the worktree > of a supermodule. There might be the case when you check > out (in given worktree) a version of a supermodule that > do not include submodule at all, but you want to know that > when going back, this submodule is to be checked out (or not). I am currently working on solving that with a patch series, that allows 2 settings. The URL will be used only to overwrite the URL from the .gitmodules file and another setting will be used to determine if we want to checkout the submodule. > > The second information needs to be per-worktree. How to > solve it, be it per-worktree configuration (not shared), > or a special configuration variable, or worktree having > unshared copy of configuration -- this what is discussed. > >> Current workflow for handling submodule URLs: >> 1) Clone the superproject >> 2) Run git submodule init on desired submodules > > Or 1-2) clone the superproject recursively, with all its > submodules. Only if the URLs are setup properly. > >> 3) Inspect .git/config to see if any submodule URL needs adaption > > Which is usually not needed. Yeah, I should have added the assertion that the .gitmodules may be out of date or such for this workflow to make sense. Usually just go with recursive clone. >> >> This long lived stuff probably doesn't make sense for the a single >> repository, but in combination with submodules (which is another way >> to approach the "sparse/narrow" desire of a large project), I think >> that makes sense, because the "continuous integration" shares a lot >> of submodules with my "regular everyday hacking" or the "I need to >> test my colleague work now" worktree. > > One thing that git-worktree would be very useful, if it could work > with submodules: you could use separate worktrees to easily test > if the supermodule works with and without its submodules present. Oh! Yeah that makes sense! > > [...] >> If you switch a branch (or to any sha1), the submodule currently stays >> "as-is" and may be updated using "submodule update", which goes through >> the list of existing (checked out) submodules and checks them out to the >> sha1 pointed to by the superprojects gitlink. > > Which might be simply a problem that submodule UI is not mature enough. > I would like to see automatic switch of submodule contents, if > configured so. Me too. Once upon a time Jens pushed for that with a series found at: https://github.com/jlehmann/git-submod-enhancements/tree/git-checkout-recurse-submodules -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html