comparison mercurial/pycompat.py @ 43085:eef9a2d67051

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

43084:c2e284cee333

    maybebytestr = identity
    sysbytes = identity
    sysstr = identity
    strurl = identity
    bytesurl = identity

    # this can't be parsed on Python 3
    exec(b'def raisewithtb(exc, tb):\n' b'    raise exc, None, tb\n')

    def fsencode(filename):

43085:eef9a2d67051

    maybebytestr = identity
    sysbytes = identity
    sysstr = identity
    strurl = identity
    bytesurl = identity
    open = open

    # this can't be parsed on Python 3
    exec(b'def raisewithtb(exc, tb):\n' b'    raise exc, None, tb\n')

    def fsencode(filename):