py3: manually import pycompat.open into files that need it
We want to eliminate the source transformer. Currently it inserts
a `from mercurial.pycompat import ...` at the top of files to alias
some builtins.
This commit replaces the implicit import of `open` with an explicit
import on files that need it and changes the source transformer to
no longer import `open`.
As part of this, we needed to store an explicit local for `open` in
the Python 2 code path in `pycompat` so the import works. (Builtins
that are automatically in scope cannot be imported.)
Differential Revision: https://phab.mercurial-scm.org/D7005
# Balto (https://bitbucket.org/lothiraldan/balto/src) is a test orchestrator
# which is compatible with all test runner that can emit the LITF
# (https://github.com/lothiraldan/litf) test format.
# The plugin for the Mercurial test runner is mercurial-litf
# (https://pypi.org/project/mercurial-litf/). Make sure to follow the
# instruction and configuration instructions here:
# https://bitbucket.org/lothiraldan/mercurial_litf/src/default/
# You can launch Balto with `balto /path/to/mercurial/tests/`
name = "Mercurial Test Suite"
tool = "mercurial"