The main thing here is writing check_string_fixed_length and
check_capped_string as returning a Validator, but we also fix issues
around passing default=None.
This is helpful for cases where an argument is supposed to be a normal
string, and we want to use a Zulip validator function to do basic
things like check its length.
These changes are in one commit, since the previous typing of check_url
does not match the centralized strict definition (object/Any vs Text),
actually already used elsewhere in validator.py, and also had a different
API.
check_url is updated here to match the API of the other check_* functions,
ie. val is an object (not Text) & returns Optional[str]. It also now checks
the value is text explicitly at run-time, which was only type-checked
previously. Tests are updated accordingly.
Originally was going to centralize this in zerver/lib/request.pyi, but this
file is not visible at run-time, being only a stub. The matching request.py
file seemed inappropriate, as it doesn't actually use ViewFuncT.
The file `zerver/lib/request.py` doesn't have type annotations
of its own; if they did, they would duplicate the annotations that
exist in its stub file `zerver/lib/request.pyi`. The latter exists
so that we can provide types for the highly dynamic `REQ` and
`has_request_variables`, which are beyond the type-checker's ken
to type-check, but we should minimize the scope of code that gets
that kind of treatment and `JsonableError` is not at all the sort of
code that needs it.
So move the definition of `JsonableError` into a file that does
get type-checked.
In doing so, the type-checker points out one issue already:
`__str__` should return a `str`, but we had it returning a `Text`,
which on Python 2 is not the same thing. Indeed, because the
message we pass to the `JsonableError` constructor is generally
translated, it may well be a Unicode string stuffed full of
non-ASCII characters. This is potentially a bit of a landmine.
But (a) it can only possibly matter in Python 2 which we intend to
be off before long, and (b) AFAIK it hasn't been biting us in
practice, so we've probably reasonably well worked around it where
it could matter. Leave it as is.
The whole thing is an error, so "message" is a more apt word for the
error message specifically. We abbreviate that as `msg` in the actual
HTTP responses and in the signatures of `json_error` and friends, so
do the same here.
In order to benefit from the modern conveniences of type-checking,
add concrete, non-Any types to the interface for JsonableError.
Relatedly, there's no need at this point to duck-type things at
the places where we receive a JsonableError and try to use it.
Simplify those by using straightforward standard typing.
This stub file allows us to annotate view functions using the actual
types present in the bodies of the functions, rather than everything
having the type REQ.
Tim Abbott
neiljp (Neil Pilgrim)
Greg Price
Eklavya Sharma
Reid Barton