There is a legacy bug I just caught, where many accounts would have the
same email but then have different casing. In extreme scenarios, this
would lead to them creating a new user with the same email, or having
issues with password reset and username lookup.
This doesn't merge in the existing duplicates, but makes sure to only
allow insensitive lowercase emails from here on out. It also will check
for emails in a case insensitive way for such things as resets and
logins if the sensitive lookup doesn't work.
The implementation was not wrong per se - email is supposed to be case sensitive
for usernames. But of course, nobody (nor do most/all email servers) treat
them that way, leading to confusion situations where the user sometimes
camelcases their email and then switches to lowercase later.
"There is a time when the operation of the machine becomes so odious,
makes you so sick at heart, that you can't take part; you can't even
passively take part, and you've got to put your bodies upon the gears
and upon the wheels, upon the levers, upon all the apparatus, and you've
got to make it stop. And you've got to indicate to the people who run
it, to the people who own it, that unless you're free, the machine will
be prevented from working at all."
Mario Savio
Sproul Hall Steps
University of California, Berkeley
December 3, 1964
