How do I update a git submodule without checking it out

Question

I am using a git submodule in a very usual way. The way how people typically update a submodule is by checking it out, pulling something in the submodule and then commiting outside.

Now, I typically don't develop those modules in the same place. For me it's more comfortable to develop those two modules in different places. How do I just tell my git project that one submodule has changed and is now at commit XYZ?

I think there's a chance that there's a setting somewhere in .git that I could modify.

Answer 1

you can do with this, as follows:

git update-index --add --cacheinfo  mode,sha1,submodule_path

the mode value can get from git ls-files --stage submodule_path

git update-index reference

Answer 2

A self-explanatory example :

git update-index --cacheinfo 160000,03d7dff560ac8ed64f16e763204b04ce91ca5faf,submodules/submodule

Explanation:

• 160000 : mode; here it indicates a directory (see doc and search for 160000)
• 03d7dff560ac8ed64f16e763204b04ce91ca5faf: the commit id (or commit hash or sha-1) in the submodule repository to which you want to point from your current repository
• submodules/submodule: path the the submodule location in the git repository, no trailing slash (gives error), no .git

Remember, this only updates the index, you are still expected to commit the change!