Store lefthook checksum in non-hook file

[mrexox]

Relates to #279

• Store lefthook config checksum not in prepare-commit-msg, but in lefthook.checksum file.
• Make sure config is synchronized when calling run command.

[Envek]

Is it a good idea to still store checksums in the hooks directory? It is not a hook now.

Maybe we should store it in .git/info instead? 🤔

Also, as far as I remember, purpose of prepare-commit-msg hook was to detect config changes and install or uninstall hooks automatically. How it will be done now?

[mrexox]

Is it a good idea to still store checksums in the hooks directory? It is not a hook now.

Maybe we should store it in .git/info instead?

Also, as far as I remember, purpose of prepare-commit-msg hook was to detect config changes and install or uninstall hooks automatically. How it will be done now?

@Envek Thank you! .git/info is much better directory for this purpose.

Well, while refactoring I have forgotten about this feature 😕. I have an idea how bring it back. We could store config file last updated timestamp with the checksum and compare it on every run command. It is cheaper that calculating checksum on every call.

If we find that the timestamp has changed, we can invoke install command, which compares the checksums and installs if necessary.

This might be not a very clean solution but I think it is more fair to let prepare-commit-msg hook to be just a usual configurable hook. (I missed this feature when I was using 0.* versions).

What do you think?