git merge banch w/ different submodule revision

["Middelschulte, Leif" <Leif.Middelschulte@klsmartin.com>]

Hi,

we're using git-flow as a basic development workflow. However, doing so revealed unexpected merge-behavior by git.

Assume the following setup:

- Repository `S` is sourced by repository `p` as submodule `s`
- Repository `p` has two branches: `feature_x` and `develop`
- The revisions sourced via the submodule have a linear history


* 1c1d38f (feature_x) update submodule revision to b17e9d9
| * 3290e69 (HEAD -> develop) update submodule revision to 0598394
|/  
* cd5e1a5 initial submodule revision


Problem case: Merge either branch into the other

Expected behavior: Merge conflict.

Actual behavior: Auto merge without conflicts.

Note 1: A merge conflict does occur, if the sourced revisions do *not* have a linear history

Did I get something wrong about how git resolves merges? Shouldn't git be like: "hey, you're trying to merge two different contents for the same line" (the submodule's revision)

Thanks in advance,

Leif