Why can't I stash submodule changes?

I’m having trouble understanding why I cannot stash changes to a submodule.

When adding a submodule to a repository (`git submodule add ./sub-repo`), I can then run `git stash` and `git stash pop` with expected results—the submodule disappears and reappears in the working tree.

However, when I try stashing an update to a submodule, `git stash` reports “No local changes to save”. The following shell script illustrates this behavior:

# Create repo mkdir test-repo cd test-repo git init git commit --allow-empty -m "Initial commit"

# Create submodule mkdir sub-repo cd sub-repo git init git commit --allow-empty -m "Initial commit" cd -

# Add submodule git submodule add ./sub-repo git commit -m "Add submodule"

# Modify submodule cd sub-repo touch foo git add foo git commit -m "Submodule changed" cd -

# Stash submodule change git stash # <---------------------------Displays "No local changes to save”

I’m trying to wrap my head around why this is the current behavior, as I suspect this is intentional but it seems unexpected. If anyone can shed any light on this, I would really appreciate it!

Thanks,

Shane