Control characters in commit messages are written to .changes file

[martinkunkel2]

I used the obs_scm service on a git repo that contained a (non-newline) control character in a commit message.
This control character was copied to the my-package.changes file.
Building the package in our private open build service worked fine. No error was reported.

But when trying to install the package, it was not found and I discovered the problem:
[ 44s] C_CREATEREPOLIB: Critical: Cannot dump XML for my-package (9d062c...): Forbidden control chars found (ASCII values <32 except 9, 10 and 13).

Question: is that something which we should handle in obs_scm?

If yes, we could avoid writing control characters to the .changes file. I would try to add a pull request for this, but need a bit of guidance at which place this shall be fixed:

• when reading the commit messages?
• when writing the .changes file?
• somewhere in between?