I did a little test, and for this program:

# from 3.7 test_asyncgen.py
def test_async_gen_iteration_01(self):
async def gen():
await awaitable()
a = yield 123

the 3.6 ASYNC_GENERATOR flag is added in the code object created for "gen()" as 3.6 does. So I infer that flag 0x200 in a code object doesn't imply the PYPY_DONT_IMPLY_DEDENT property. Does that mean that in 3.6 PYPY_DON'T_IMPLY_DEDENT flag will never appear in a code object? Or just for 3.6 and above or for all Pypy versions?

I don't want to try guessing what the principle being used is looking at all versions of Pypy across all the pypy-specific flags listed in pypy/interpreter/astcompiler/consts.py if there is a principle being followed and someone can just tell me what it is or point to a document that describes what's up here.

On Mon, Dec 16, 2019 at 5:33 AM Armin Rigo <armin.rigo@gmail.com> wrote:

Hi,

On Mon, 16 Dec 2019 at 11:24, Rocky Bernstein <rb@dustyfeet.com> wrote:
> I have a cross-version Python bytecode disassembler xdis (https://pypi.org/project/xdis/) and I notice that flags 0x0100 and 0x0200 (DONT_IMPLY_DEDENT and SOURCE_IS_UTF8 respectively) conflict in Pypy 3.6 with Python 3.6's ITERABLE_COROUTINE and ASYNC_GENERATOR.

Looking in the CPython 3.6 source code, I see that
PyCF_DONT_IMPLY_DEDENT = 0x0200 as well there, even though
``inspect.CO_ASYNC_GENERATOR`` is also 0x0200. The same with
PyCF_SOURCE_IS_UTF8 = 0x0100 and ``inspect.CO_ITERABLE_COROUTINE``.
So the conflict you're talking about seems to exist in CPython 3.6
too.

Can you give us a concrete example of code where CPython 3.6 differs
from PyPy 3.6?

CPython 3.6 bytecode differs from PyPy 3.6 bytecode and so far as I know it CPython bytecode version x.y differs from Pypy version x.y Otherwise I wouldn't have to go through the extra effort to try to add code to make Pypy disassembly and decompilation possible in a cross-version way. I have for example that there are opcodes FORMAT_VALUE, BUILD_STRING and JUMP_IF_NOT_DEBUG for example in Pypy3.6 that are not in CPython (among I think other opcodes).

But again I'd prefer not to guess this kind of thing if it is documented somewhere or someone who knows this already can just let me know.

A bientôt,

Armin.