This removes the assertions that checked plugin devs didn't do anything
overly bad in favour of using mypy to ensure appropriate type-checking.
It also moves the ProgressCallback typing information to constants in
order to avoid circular imports (since constants doesn't import
anything).
This includes:
* Better ways of checking empty lists
* Not shadowing builtin functions like filter
* Preventing invalid slash warnings by marking strings as regexps
* Removing unnecessary brackets
* Lowercase variable names
* Adding/updating parameters in docstrings
* Removing unused code (lines not chunks)
* Change in not a member tests
* Changing some methods to static
* Shorting range membership checks
* Missing parameters
* Make some exception handlers more specific
* Don't define a lambda to a variable
* A few more instance checks to help type checkers
Relented on the strict import of direct objects/classes for the typing
module only. Typing module components can be directly imported because
it makes the code really painful to read and write otherwise.
This is still in-line with the python style guide adopted from Google at
http://google.github.io/styleguide/pyguide.html section 2.2.
We use the jar scheme because that's actually registered with the right
bodies, even if the syntax is a bit weird. The contents is still
processed by the ResourceAccessor meaning it can be compressed with any
of the supported compression methods.
This might benefit from a recache of the linux banners, although it
should continue to work no recache is performed.
We're now in a position to add support for loading symbols directly from
zip files by altering the ResourceAccessor and adding code to the
symbol finder.
Consider refactoring out the various URL openning code into
one that just returns the open file handle. This would require changing
the config option of "filename" to "location" and rejigging a few other
bits elsewhere, but would centralize and make it more managable.
Mike Auty