Opposite/reverse of "git submodule absorbgitdirs"?

Question

How can I do the reverse of git submodule absorbgitdirs? I.e. move a submodule's .git information out of superproject/.git/modules/<module> and back to the superproject/path/to/<module>/.git directory?

I still want <module> to be a submodule of superproject, I just don't want <module>'s .git directory info in superproject's .git/modules directory.

Jobie

Answer 1

Note that this would make superproject/path/to/<module>/ a nested Git repo, whose SHA1 would still be recorded by the parent project.

To keep the exact same state, you can copy superproject/.git/modules/<module> and rename to superproject/path/to/<module>, and rename <module>/<module> to <module>/.git.

Then you can use the git submodule deinit to remove the submodule:

mv asubmodule asubmodule_tmp
git submodule deinit -f -- a/submodule    
rm -rf .git/modules/a/submodule

# if you want to leave it in your working tree
git rm --cached asubmodule
mv asubmodule_tmp asubmodule

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I still want to be a submodule of superprojec

Then its .git folder would be in superproject/.git/modules/<module>

submodule absorbgitdirs does not leave any choice:

If a git directory of a submodule is inside the submodule, move the git directory of the submodule into its superprojects $GIT_DIR/modules path and then connect the git directory and its working directory by setting the core.worktree and adding a .git file pointing to the git directory embedded in the superprojects git directory.

I don't see in git config any configuration that might move $GIT_DI R/modules.

absorbgitdirs was introduced in commit f6f8586 for Git 2.12 (Q4 2016)
Its tests shows it expects to use GIT_DIR/modules.

Older Git (before Git 1.7.8, Oct. 2011) had a .git directly inside the submodule folder.

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As noted by Jeremiah Rose in the comments:

Another use case is: if you are using a Docker container to use git commands inside a submodule, where the container can't see the superproject and errors out. :(

Androcles

I could have sworn at some point you could have a submodule and not have to have it's .git info living in superproject/.git/modules/<module>. – Jobie

@Jobie Yes: older versions of Git had the .git directly in the submodule folder. – Androcles

Experimenting a bit, looks like cloning the sumodule's repo, then git submodule add ./path/to/<submodule> leaves the submodule's .git directory in-place. But a direct git submodule add <module's URI> will put the .git info in superproject/.git/modules. So file move dance you suggested should work, given a final git submodule add ./path/to/<submodule> to re-submodule. Thanks! – Jobie

@Jobie I have updated the answer to indicate when a submodule .git moved to GIT_DIR/modules, and when absorbgitdirs was added to Git. – Androcles

@genpfault: Out of interest, is there a particular reason that you want to do this? There is a good reason that this changed in Git. It is much safer to use the modern layout. – Kight

@CharlesBailey: Working around a broken script that expected a "real" .git directory instead of the submodule stub .git file. Definitely looks like fixing the script is the way to go. – Jobie

@CBBailey: Another such case happens when a build script queries Git for versioning tags (eg. git describe), but they're unavailable because the parent gitdir is unavailable (eg. building in a separate Docker context). – Marsden

Another use case is if you are using a Docker container to use git commands inside a submodule, where the container can't see the superproject and errors out. :( – Signification

@JeremiahRose Good point. I have included your comment in the answer for more visibility. – Androcles

Answer 2

I wrote a script to do this. Add this to your ~/.gitconfig:

[alias]
    extract-submodules = "!gitextractsubmodules() { set -e && { if [ 0 -lt \"$#\" ]; then printf \"%s\\n\" \"$@\"; else git ls-files --stage | sed -n \"s/^160000 [a-fA-F0-9]\\+ [0-9]\\+\\s*//p\"; fi; } | { local path && while read -r path; do if [ -f \"${path}/.git\" ]; then local git_dir && git_dir=\"$(git -C \"${path}\" rev-parse --absolute-git-dir)\" && if [ -d \"${git_dir}\" ]; then printf \"%s\t%s\n\" \"${git_dir}\" \"${path}/.git\" && mv --no-target-directory --backup=simple -- \"${git_dir}\" \"${path}/.git\" && git --work-tree=\"${path}\" --git-dir=\"${path}/.git\" config --local --path --unset core.worktree && rm -f -- \"${path}/.git~\" && if 1>&- command -v attrib.exe; then MSYS2_ARG_CONV_EXCL=\"*\" attrib.exe \"+H\" \"/D\" \"${path}/.git\"; fi; fi; fi; done; }; } && gitextractsubmodules"

and then run:

git extract-submodules [<path>...]

If you run it without specifying any submodules, it will extract all of them.

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If you want to see what the code is doing, just change

&& gitextractsubmodules

at the end to

&& type gitextractsubmodules

and then run the command without arguments to make Bash pretty-print the function body.

Stavropol

Doing what you suggest in order to see what the code is doing does not pretty-print the function body. It seems, instead, that it just tells you the type: (i.e. gitextractsubmodules is a shell function. – Shakiashaking

@Rik: Interesting, thanks for the feedback. Try declare -f instead. What shell are you using? – Stavropol

I'm using terminal on Debian - though I've tried Terminology too. The default interactive shell is /bin/bash, the default non-interactive is dash. I think it's getting run through the non-interactive and is as such ash and thus bash commands are not available. I've tried type -f with the error -f not found, I've tried typeset -f, declare -f, whence, and all of the latter commands are not found. Seems there isn't a solution without using git bash. – Shakiashaking

@Rik: In that case I think what you want to do is to turn this into a .sh script file with #!/bin/bash and call that. – Stavropol

I've cleaned up this one-liner to a human readable posix script and added support for nested submodules. gist.github.com/Jamesits/64f9daf3f9467a8aee9a1a5c6e970ea3 – Malvie

As a warning to anyone using this: If you have a submodule that contains submodules, this will break those child submodules. You will need to go to each broken submodule and deinit/init those submodules. – Deland