On Thu, Oct 14, 2021 at 01:12:11PM -0400, Derrick Stolee wrote: > > On 10/13/2021 2:51 PM, Emily Shaffer wrote: > > On Thu, Aug 19, 2021 at 09:09:46PM -0400, Derrick Stolee wrote: > >> but I do have some concerns that > >> we have not covered all the cases that could lead to the relative path > >> needing an update, such as a 'git checkout' across commits in the super- > >> project which moves a submodule. > >> > >> Leading more to my confusion is that I thought 'git submodule update' > >> was the way to move a submodule, but that does not appear to be the case. > >> I used 'git mv' to move a submodule and that correctly updated the > >> .gitmodules file, but did not run any 'git submodule' subcommands (based > >> on GIT_TRACE2_PERF=1). > > > > During a live review a few weeks ago it was pointed out, I forget by > > who, that this whole series would make a lot more sense if it was > > treated as the path from the submodule's gitdir to the superproject's > > gitdir. I think this would also fix your 'git mv' example here, as the > > submodule gitdir would not change. > > I think that's a great way to deliver similar functionality without > the issues I was thinking about. > > >> You mention in an earlier cover letter that this config does not need to > >> exist, but it seems to me that if it exists it needs to be correct for us > >> to depend on it for future features. I'm not convinced that we can rely > >> on it as-written, but you might be able to convince me by pointing out > >> why these submodule movements are safe. > > > > Yeah, that is a good point, and I wonder how to be defensive about > > this... Maybe it makes sense to BUG() if we don't find the > > superproject's gitdir from this config? Maybe it makes sense to warn > > (asking users to 'git submodule update') and erase the incorrect config > > line? > > I think we can complain with something like a die() if the config points > to data that doesn't make sense (not a .git directory), but a BUG() is > too heavy-handed because it can just be a user modifying their config > file incorrectly. Ok. Having re-thought since the other day, I think I will skip the wrapper for this reroll and instead propose it in a series that actually uses this pointer (so, the shared submodule-and-superproject config), if it looks like we'd want one. I expect doing that work in the context of a caller will make the correct behavior a little more clear - in the context of this series I'm not totally sure what we'd want to do. > > I'm happy to shut down a process because a user messed with config > incorrectly. Since your proposed change allows operations like 'git mv' > to move submodules without needing to change this config, I'm much > happier with the design. It becomes impossible for the config to get > out of sync unless the user does something outside of a Git command. Thanks for pulling the context back up here. I appreciate it. Like I mentioned in reply to your comment on v4, look for a reroll in the next 30 minutes or so (assuming the CI passes ok). - Emily
