Hi, I have a stand-alone project, "foo", that I work on myself. The "foo" project is included as a submodule in two other projects, "bar" and "baz", that I don't have any direct affiliation with. Semi-regularly, I like to keep tabs on bar and baz, to see what versions of foo they are using, what changes they have made to foo, and if there are things I could pick up from them, or maybe even things they could learn from eachother. Doing this currently is quite tedious: 1. Clone/Fetch bar and initialize/update its foo submodule 2. Clone/Fetch baz and initialize/update its foo submodule 3. Set up remotes bar_foo and baz_foo in my main foo repo, pointing to bar/foo and baz/foo, respectively. Fetch. 4. Create tags bar_foo_current and baz_foo_current pointing to the foo SHA1 sum recorded in baz and baz, respectively. 5. Start comparing bar_foo_current and baz_foo_current to eachother, and to my own master branch. Now, bring this into a larger company setting. There are many (~100) different foo-type projects owned by (~50) different developers. These projects are included as submodules by several (~20) different bar/baz-type projects. In addition, each bar/baz-type project has multiple (~3) branches using various versions of the foo-type submodules. Finally, throw in questions like "What are the differences in submodule FOO between branch X of BAR, and branch Y of BAZ?", for random values of FOO, X, BAR, Y, and BAZ. It is apparent that the above approach just doesn't cut it. Ironically, these questions are fairly easily answered by our current CVS setup (which applies the supermodule tags/branches to the entire source tree (including submodules)): 1. cd FOO 2. cvs diff -r BAR_X -r BAZ_Y What I'd like, is some way to refer to the state of a repo as specified by the appropriate submodule blob in a superproject commit. Ideally this should be done remotely as well, so that I don't have to clone the entire superproject just to get at the appropriate submodule blob. Crude Proposal: Define a new "git submodule" subcommand that takes three arguments: <superURL> <tree-ish> <submoduleName> The command does the following steps: 1. Locate git repo at <superURL> 2. Resolve <tree-ish> to the tree object within the git repo in #1 3. Locate .gitmodules within the tree object in #2 4. Lookup <submoduleName> in .gitmodules to find its path and URL 5. Locate the submodule blob from the path in #4 within the tree from #2 6. Record the object name (SHA1) stored in the submodule blob from #4 7. Fetch the object name (#7) from the submodule repo (its URL was found in #4) into the local git repo 8. Store a reference to the fetched object Given the above command, the tedious steps described at the top can be reduced to the following (which is reasonably close to the equivalent CVS commands): 1. git submodule magic-command url/to/bar master foo 2. git submodule magic-command url/to/baz master foo 3. Start comparing the fetched refs to eachother, and to my own master branch. If this sounds reasonable, I'd be happy to start coding the above proposal. Have fun! :) ...Johan -- Johan Herland, <johan@xxxxxxxxxxx> www.herland.net -- 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
