Re: [PATCH] iotests: Fix up python style in 300

[John Snow <jsnow@redhat.com>]

On 2/26/21 2:04 AM, Vladimir Sementsov-Ogievskiy wrote:
> 16.02.2021 02:21, John Snow wrote:
>> On 2/15/21 5:05 PM, Eric Blake wrote:
>>> Break some long lines, and relax our type hints to be more generic to
>>> any JSON, in order to more easily permit the additional JSON depth now
>>> possible in migration parameters.  Detected by iotest 297.
>>>
>>> Fixes: ca4bfec41d56
>>>   (qemu-iotests: 300: Add test case for modifying persistence of bitmap)
>>> Reported-by: Kevin Wolf <kwolf@redhat.com>
>>> Signed-off-by: Eric Blake <eblake@redhat.com>
>>
>> Reviewed-by: John Snow <jsnow@redhat.com>
>>
>>> ---
>>>   tests/qemu-iotests/300 | 10 ++++++----
>>>   1 file changed, 6 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/tests/qemu-iotests/300 b/tests/qemu-iotests/300
>>> index 63036f6a6e13..adb927629747 100755
>>> --- a/tests/qemu-iotests/300
>>> +++ b/tests/qemu-iotests/300
>>> @@ -22,7 +22,7 @@
>>>   import os
>>>   import random
>>>   import re
>>> -from typing import Dict, List, Optional, Union
>>> +from typing import Dict, List, Optional
>>>
>>>   import iotests
>>>
>>> @@ -30,7 +30,7 @@ import iotests
>>>   # pylint: disable=wrong-import-order
>>>   import qemu
>>>
>>> -BlockBitmapMapping = List[Dict[str, Union[str, List[Dict[str, str]]]]]
>>> +BlockBitmapMapping = List[Dict[str, object]]
>>>
>>
>> Assuming iotest 297 didn't yap about this, I think this has the 
>> necessary power for this file and we don't have to work any harder.
>>
>> If in the future you try to treat e.g. bmap['persistent'] as a 
>> particular kind of value (string? bool? int?) mypy will likely 
>> complain about that a little, saying it has no insight into the type 
>> beyond "object".
>>
>> If *that* becomes annoying, you can degrade this type to use 'Any' 
>> instead of 'object' and even those checks will cease.
> 
> Probably at some future moment we'll have generated python types for 
> QAPI structures ? :)
> 

That's my hope, yes!

Typing the QAPI generator is something I see as a step to doing this so 
that we can safely work on the QAPI generator a bit more vigorously.

Marc-Andre is adding rust backends, I'd like to add either a Python or a 
JSON-Schema backend to help generate a fully typed SDK for us in Python.

I don't know how suitable those tools will be to use in the test suite; 
I suspect that every last build of QEMU from the development tree will 
have to possibly re-generate such a Python module.

When I get a little closer to a prototype for this I will try to 
announce it. In the meantime I am very fastidiously trying to strictly 
type the QAPI generator and move it to ./python/qemu/qapi.

--js