isHgDirectory function short-circuits if it finds a .git directory

[rlipscombe]

...which is probably not what you want if you've got a git repo sharing with an hg directory. Though whether that's something you want is probably up for discussion.

[jrsconfitto]

Pretty sure it's a feature, not a bug. See 7dddbe7c3e4c9870f7c633f7a75f26564930e310