Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py

Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py

Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py

Col: 80
 E501 line too long (85 > 79 characters)

Col: 80
 E501 line too long (89 > 79 characters)

Col: 9
 E303 too many blank lines (2)

Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py

I am a little confused about how this all works, but perhaps a docstring for clean() might help with that?
Otherwise, these are just mostly comments on style. :)

Missing a docstring for the function here?

Multi-line strings should use parenthesis, according to: https://www.notion.so/reviewboard/Python-Coding-Style-Guide-f9a0e51ee0cf40379fcbbae40bbbec04#ec5a472e3610412ea99d0835a1faf2c0

Correct me if I'm wrong: I don't think we need a blank line here.

Can these two if statements be merged into one?
A question I would have with this is if, for the example code:
if foo and bar():

Will bar() be executed if foo evaluates to false? 
Otherwise, I think these two statements should be merged into one.

I don't think the call is long enough to warrant this?
I think if request started on the same line as ratelimited() and all other arguments were aligned with that, that would be better. 
So, example 2 instead of example 3 from what's listed here: https://www.notion.so/reviewboard/Python-Coding-Style-Guide-f9a0e51ee0cf40379fcbbae40bbbec04#c8f86d436ebc4a5198ff42612b3fef92

A parenthesis instead of a backslash?

Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py

Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py

 'settings' imported but unused

 'DEFAULT_KEY' imported but unused

Col: 17
 E128 continuation line under-indented for visual indent

Col: 17
 E128 continuation line under-indented for visual indent

 'settings' imported but unused

 'DEFAULT_KEY' imported but unused

Col: 17
 E128 continuation line under-indented for visual indent

Col: 17
 E128 continuation line under-indented for visual indent

Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py

Col: 25
 E128 continuation line under-indented for visual indent

Col: 25
 E128 continuation line under-indented for visual indent

Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py

This should be marked for translation with ugettext.

Same comment wrt your djblets change.

Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py

Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py

No blank line here, since from the point of view of the Review Board codebase, djblets is a third-party module.

"informs the user"
"have been exceeded."

This doesn't validate the clean field, but rather validates the form.
These docs also need a "Returns" section, like:

"""
...

Returns:
    dict:
    The cleaned data for all fields in the form.
"""

"Djblets's"

"if the number"
"were already exceeded"

Alignment is off. In this case, it's best to wrap like:

raise forms.ValidationError(
    _('...'))

Blank line between these.

Throwing away all validation errors will mean that things like username or password validation will go away, and we'll allow for things like duplicate usernames.

"for a given user"

We're calling this a second time, which we don't want to do. The parent clean() should only be called once. It's very possible for there to be side effects otherwise.
I'm actually a bit confused about what this method is trying to do. Shouldn't this all solely live in Djblets? I woudn't expect this form to have to do much of anything, just inherit from a mixin in Djblets that implements all this.

Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py

Col: 80
 E501 line too long (80 > 79 characters)

Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py

Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py

 local variable 'result' is assigned to but never used

Col: 80
 E501 line too long (81 > 79 characters)

Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py

Ship It!

Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py

 local variable 'e' is assigned to but never used

Tool: PEP8 Style Checker
Processed Files:
    reviewboard/accounts/forms/auth.py



Tool: Pyflakes
Processed Files:
    reviewboard/accounts/forms/auth.py

Ship It!

Technically, this should be self.cleaned_data = super(...).clean()

is None

RR dependencies should live in the depends on field, not the description.

Diff revisions 19 and 20 look like the wrong change, but 18 looks good. Landing with a few small cleanups.