Python 2 Cleanup tracking issue

A list of cleanups and improvements we can make when dropping python 2.

Relates to #767. Maintainers, please add items to this list / edit the list to link PRs.

Easy changes:

If you’re a new contributor, these are a great place to start.

• Adjust (#1337) https://github.com/cocotb/cocotb/blob/9caf77cb6ceae739858ecd4a3760631470aac77c/setup.py#L59
• Change minimum supported version in documentation (gh-1341)
• Remove 2.7 version from Travis CI setup
• Remove reference from tox.ini
• Remove function isclose from tests/test_cases/test_cocotb/test_cocotb.py (#1489)
• Combine cocotb_test and cocotb_test_35 testbenches (#1489)
• Remove from __future__ import line from Python files (but not Makefile.pylib.*) (gh-1579)
• Remove (object) from class MyClass(object): (gh-1579)
• use type(self) instead of self.__class__. (gh-1579)
• Use __class__.__qualname__ instead of __class__.__name__
• Remove all __nonzero__ functions which alias __bool__ (gh-1579)
• Remove 2x “# NOTE: isclose is a Python 3.5+ feature” from documentation/source/coroutines.rst (gh-1576)
• Update/check installation instructions in documentation and READM
• Remove the conditional compilation here: https://github.com/cocotb/cocotb/blob/ad1e718eab6a107b56c47032f53f282f7d2dbae0/examples/endian_swapper/cosim/io.c#L116.
• Marginal:
  • make u"" strings normal strings (e.g. in documentation/source/conf.py) (gh-1579)
  • Move to format string language instead of using old modulus string formatting.

More involved

• Delete https://github.com/cocotb/cocotb/blob/master/cocotb/share/lib/simulator/simulatormodule_python2.c, and merge https://github.com/cocotb/cocotb/blob/master/cocotb/share/lib/simulator/simulatormodule_python3.c with https://github.com/cocotb/cocotb/blob/master/cocotb/share/lib/simulator/simulatormodule.c (#1342)
• Removes internal uses of cocotb./_py_compat (#1434)
• Remove cocotb.outcome hacks for python 2 (re __traceback__)s (gh-1338)
• Clean up “Before Python 3.3” part in documentation/source/coroutines.rst (#1341)
• Remove PY_MAJOR_VERSION < 3 code in gpi_embed.c
• Remove or deprecate function ReturnValue in cocotb/cocotb/result.py (#1489)
  • Remove usage of function ReturnValue in our tests and examples
  • Remove internal uses of ReturnValue (gh-1440)
• Replace reject_remaining_kwargs with direct syntax (#1339)
• Change coroutines to use async def, to teach good practice, in:
  • tests (filed separately as gh-1731)
  • docs (gh-1576)
  • examples (filed separately as gh-1730)

Very involved

• Fix all of the “binary string” interfaces to actually use bytes
  • cocotb.utils.hexdump (gh-1519)
  • cocotb.utils.hexdiffs (gh-1519)
  • BinaryValue.buff (gh-1514)
  • cocotb.generators.byte (gh-1493) (gh-1514)
  • All of the drivers that produce binary data streams (#1545, gh-1514) (h
• Change all library coroutines to use async def, for speed (gh-1523)
• Add type annotations (for user-facing code) Filed separately as gh-1582

[ktbarrett]

@eric-wieser I was documenting the interfaces on #1526 when I ran into this, which is why it has no annotations.

def fork(coro: Union[Coroutine, cocotb.decorators.RunningTask]) -> cocotb.decorators.RunningTask:
    # ...

[cmarqu]

Not all of those are strictly cleanup:

• remove from __future__ import line from Python files (but not Makefile.pylib.*)
• Remove (object) from def MyClass(object):
• Use __class__.__qualname__ instead of __class__.__name__
• Add type annotations (for user-facing code)