Re: fatal: cannot rebase with locally recorded submodule modifications

[Shourya Shukla <shouryashukla.oo@gmail.com>]

Hello Brice,

The error you are facing here is actually a bug in the
'git pull' command[1]. When one tries to use the
'--recurse-submodules' tag with the command, it tends to fail.

> Why is failing here?

Going into a bit detail of 'git pull', the command actually
is a combination of 'git fetch' and 'git merge'(unless any
other tag is specified i.e. 'rebase' here which would mean
a fetch followed by a rebase). Quoting from the documentation:

> Using --recurse-submodules can only fetch new commits in already
checked out submodules right now

Using the '--recurse-submodules' tag will try merging/rebasing any
changes(updations, additions, deletions, etc.) made to the fetched
submodule(s) from upstream, i.e. the _un-checked out_ submodules into
our local repository which will cause the error to be thrown as it is
not supported right now. This will therefore create the detached HEAD
just like the one you obtained.

The "workaround" is to do a 'git fetch' and then merge again after the
'git pull <tag> --recurse-submodules'.

The presence/absence of 'git reset --hard' before the pull  won't create
any difference to this error in my opinion.

Regards,
Shourya Shukla

[1]: https://git-scm.com/docs/git-pull#_bugs