* remove references to basestring & unicode (use relevant pycompat
helpers)
* remove some str calls (either entirely or replaced by relevant
helper, either text or native)
* use better API to avoid unnecessary conversions
* remove some XML declarations in views
* Python 3.4 adds new convenient bytecode-inspection API to dis which
is nice, however Python 3.6 also switches from the old bytecode to a
new wordcode which breaks _get_opcodes and *requires* that we use
the new API
* add various opcodes which either were added in Python
3 (CALL_FUNCTION_EX) or were only used for some small corners of
Python 2 but have been expanded or despecialised in Python
3 (BUILD_SLICE)
In Python 2, to raise a new exception but reuse a traceback requires a
special form of ``raise`` (``raise etype, evalue, tb``).
In Python 3, this is now done via a ``with_traceback`` method on
exception objects.
However this requires a bit of trickery as the former is invalid
syntax in Python 3, hence pycompat bridge created via an exec for
Python 2.
In Python 3:
* various builtins and dict methods were changed to return
view/iterable objects rather than lists
* and the separate Python 2 view/iterable builtins and methods were
removed altogether
This is problematic when using these items as list (which the happens
repeatedly in Odoo), but more viciously when iterating *multiple times*
over them (which also happens, which I've messed up multiple times while
writing this, and which is a pain to debug even when you've just created
the issue).
Convert all code using these to semantics-matching cross-version
helper functions to get the LCD behaviour between P2 and P3, and
forbid the builtins via lint.
issue #8530