On Thu, 12 Apr 2018 16:36:32 -0700 Stefan Beller <sbel...@google.com> wrote:
> Hi Antonio, > Hi Stefan, > On Thu, Apr 12, 2018 at 3:20 PM, Antonio Ospite <a...@ao2.it> wrote: > > Hi, > > > > vcsh[1] uses bare git repositories and detached work-trees to manage > > *distinct* sets of configuration files directly into $HOME. > > > > In general, submodules have worked perfectly fine with detached > > work-trees for some time[2,3,4]. > > > > However when multiple repositories take turns using the same directory > > as their work-tree, and more than one of them want to use submodules, > > there could still be conflicts about the '.gitmodules' file because git > > hardcodes this path. > > [...] > > > So this series proposes a mechanism to set an alternative path for the > > submodules configuration file (from now on "gitmodules file"). > [...] > > Expanding on that change the first patch in the series makes the path > > customizable exposing a 'core.submodulesFile' configuration setting. > > I guess the similarity to core.ignoreFile is desired here. Although these > mechanisms are very different. > The option name is similar to 'core.excludesFile' also because, when I started, I first looked at how multiple ignore files were used, so I may have been influenced by that. I acknowledge that the two mechanisms are different, in particular because git *writes* the gitmodules file itself. I am not opposed to change the name, something like 'core.submodulesConfigFile' might highlight that the syntax of the file is the one of git config, but I think it's too long. > > The new configuration setting can be used to set an *alternative* > > location for the gitmodules file; IMHO there is no need to provide > > *additional* locations like in the case of exclude files. > > I think there *may* be a need for additional files. > Currently there is only the .gitmodules file and the configuration > in .git/config overriding settings from .gitmodules. > > There was some discussion on the mailing list in the past, which > presented a intermediate layer in between these two places, in > a special ref, such that: > base is in .gitmodules > overwritten via refs/meta/submodules:.gitmodules > overwritten via the .git/config > > The intermediate would be a config file that is tracked on another > ref. This (a) decouples main project history from submodule history > and (b) makes it easier to distribute as it is part of the repository. > > For example (a) is desired if you dig up an old project and the > submodules have all moved from one git hosting provider to another. > Another example would be when you fork a project with submodules > and don't want to mess with the main history but you just want to > adjust the submodule URLs. That is possible with such an intermediate > additional place. > > For (b) you can imagine the fork that you want to distribute in your > community and you don't want to tell everyone to change the > submodule URLs, but instead you can provide them with a prepared > .gitmodules file, that they have to place into that special ref (which > can be done via fetching). > > I digress as these ideas seem to be orthogonal to your patch series, > just FYI. prior discussion starting at: > https://public-inbox.org/git/1462317985-640-1-git-send-email-sbel...@google.com/ > I recall there was a better discussion even prior to that, but have no > link handy. > Just to understand, is that 'refs/meta/submodules:.gitmodules' file meant to be managed manually? Or do you imagine some options to instruct "git submodule" to *write* to that file instead of .gitmodules? In the latter case your idea could cover my use case too, couldn't it? But most importantly, is this realistically going to be added? Currently I am not that familiar with the git code base to do it myself, and I've never explicitly dealt with special refs in git. The approach of this patch series is a lot simpler, and something I can work on in my spare time. Presumably (b) could even be partially supported with my changes, by having both '.gitmodules' and some custom '.gitmodules-alternative' files in the repository and tell users to clone with: git clone --config core.submodulesFile=.gitmodules-alternative URL Not as clean as your idea but doable. [...] > > Since the gitmodules file is meant to be checked in into the repository, > > the overridden file path should be relative to the work-tree; is there > > a way to enforce this constraint at run time (i.e. validate the config > > value), or is it enough to have it documented? > > I think we'd want to check at run time, if we need this constraint. > I'll look into it once we decide which the way to go. Thank you. Ciao, Antonio -- Antonio Ospite https://ao2.it https://twitter.com/ao2it A: Because it messes up the order in which people normally read text. See http://en.wikipedia.org/wiki/Posting_style Q: Why is top-posting such a bad thing?
