've made a code review on the usage of case sensitivity inside James and I found a lot of inconsistencies.
We currenlty have an <ignoreCase> option inside the James block and have 2 methods in the UsersRepository interface: contains and containsCaseInsensitive.
This would be ok if every piece of code using the UsersRepository to check for users was checking ignoreCase first and then call one or the other method, but this does not happen in out code.
Here a few inconsistencies:
1) our default "addUser" method for AbstractUsersRepository uses containesIgnoreCase before adding an user: this mean you can't add 2 users with the same name but different letter-cases even if you have ignoreCase=false.
2) fetchmail checks for localusers always using the caseInsensitive search, so it could do the wrong things when ignoreCase is false.
3) few places use the MailetContext.isLocalEmail, implemented by James and following the ignoreCase directive, but most code use directly the userrepository.contains() that is case sensitive: you understand how many problems this could lead to. (as an example if you have ignorecase on and using remotemanager you try to add an user that is already present using the same lettercase remotemanager tell you that the user already exists, while if you use a different lettercase you receive a generic error).
That said my proposal is:
1) Move the ignoreCase configuration to the UsersRepository
2) Remove the containsIgnoreCase from the UsersRepository interface (we don't need it anymore). Maybe we should keep this as deprecate as the first step and let it revert to contains(name.toLowerCase), so we keep a better backward compatibility.
3) Remove/deprecate getUserByNameCaseInsensitive: we don't use this anywhere.
4) Allow the administrator to add 2 users with the same name but different letter-case (when using ignoreCase=false)
5) Make sure that our current implementations switch to all lowercase names where ignoreCase is activated: add a comment to let the user know of problems when having 2 users with different capitalization
6) We should also deprecate addUser(User user) and addUser(String username,Object attributes) as all of our code now use only addUser(String username, String password).
See http://mail-archives.apache.org/mod_mbox/james-server-dev/200609.mbox/%3c5127012.83921158508122583.JavaMail.email@example.com%3e for the complete (ongoing) thread.