In the debug logs, always log if a dependency lookup raises a
DependencyException. In the `required: false` case, this information
would otherwise disappear forever, and we would just not even log that
we tried it -- it doesn't appear in "(tried x, y and z)".
In the `required: true` case, we would re-raise the first exception if
it failed to be detected. Update the raise message with the same
information we print to the debug logs, indicating which dependency and
which method was used in the failing attempt.
functools.partial preserves information about how the method was
created, lambdas do not. Also, we just want to freeze the first argument
and forward the rest anyway.
This also lets us get rid of a mypy error that was being ignored.
Using future annotations, type annotations become strings at runtime and
don't impact performance. This is not possible to do with T.cast though,
because it is a function argument instead of an annotation.
Quote the type argument everywhere in order to have the same effect as
future annotations. This also allows linters to better detect in some
cases that a given import is typing-only.
A bunch of files have several T.TYPE_CHECKING blocks that each do some
things which could just as well be done once, with a single `if`
statement. Make them do so.
'{}'.format('foo') for any given value of 'foo' (in this case, a
function returning a string), can always just be 'foo' directly, which
is a lot more readable.
We have a lot of these. Some of them are harmless, if unidiomatic, such
as `if (condition)`, others are potentially dangerous `assert(...)`, as
`assert(condtion)` works as expected, but `assert(condition, message)`
will result in an assertion that never triggers, as what you're actually
asserting is `bool(tuple[2])`, which will always be true.