How to check if a git commit author is valid

Question

In a repository where I cant set both user.name and user.email configurations I need to script a commit with:

commit -a --message "message" --author="author"

Message and author are parametrized.

When I commit with a wrong author (not present on rev-list and bad formatted for git) I get:

fatal: --author 'bad-formatted-author' is not 'Name ' and matches no existing author

Is there any way to check against git if the author is valid before the commit?

Answer 1

Use git commit -a --message "message" --author="author" --dry-run.

The added --dry-run flag will make git commit not actually commit anything but still exit non-zero if the --author option string given is invalid.

Note, however, that there may be other reasons the exit status is non-zero, such as the commit being empty (i.e. not having any changes).