Re: [PATCH v10 10/14] iotests: add hmp helper with logging

[Max Reitz]

On 31.03.20 16:00, Kevin Wolf wrote:
> Am 31.03.2020 um 12:21 hat Max Reitz geschrieben:
>> On 31.03.20 02:00, John Snow wrote:
>>> Minor cleanup for HMP functions; helps with line length and consolidates
>>> HMP helpers through one implementation function.
>>>
>>> Although we are adding a universal toggle to turn QMP logging on or off,
>>> many existing callers to hmp functions don't expect that output to be
>>> logged, which causes quite a few changes in the test output.
>>>
>>> For now, offer a use_log parameter.
>>>
>>>
>>> Typing notes:
>>>
>>> QMPResponse is just an alias for Dict[str, Any]. It holds no special
>>> meanings and it is not a formal subtype of Dict[str, Any]. It is best
>>> thought of as a lexical synonym.
>>>
>>> We may well wish to add stricter subtypes in the future for certain
>>> shapes of data that are not formalized as Python objects, at which point
>>> we can simply retire the alias and allow mypy to more strictly check
>>> usages of the name.
>>>
>>> Signed-off-by: John Snow <address@hidden>
>>> ---
>>>  tests/qemu-iotests/iotests.py | 35 ++++++++++++++++++++++-------------
>>>  1 file changed, 22 insertions(+), 13 deletions(-)
>>
>> Reviewed-by: Max Reitz <address@hidden>
>>
>>> diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
>>> index b08bcb87e1..dfc753c319 100644
>>> --- a/tests/qemu-iotests/iotests.py
>>> +++ b/tests/qemu-iotests/iotests.py
>>> @@ -37,6 +37,10 @@
>>>  
>>>  assert sys.version_info >= (3, 6)
>>>  
>>> +# Type Aliases
>>> +QMPResponse = Dict[str, Any]
>>> +
>>> +
>>>  faulthandler.enable()
>>>  
>>>  # This will not work if arguments contain spaces but is necessary if we
>>> @@ -540,25 +544,30 @@ def add_incoming(self, addr):
>>>          self._args.append(addr)
>>>          return self
>>>  
>>> -    def pause_drive(self, drive, event=None):
>>> -        '''Pause drive r/w operations'''
>>> +    def hmp(self, command_line: str, use_log: bool = False) -> QMPResponse:
>>> +        cmd = 'human-monitor-command'
>>> +        kwargs = {'command-line': command_line}
>>> +        if use_log:
>>> +            return self.qmp_log(cmd, **kwargs)
>>> +        else:
>>> +            return self.qmp(cmd, **kwargs)
>>
>> Hm.  I suppose I should take this chance to understand something about
>> mypy.  QEMUMachine.qmp() isn’t typed, so mypy can’t check that this
>> really returns QMPResponse.  Is there some flag to make it?  Like
>> --actually-check-types?
> 
> There is --check-untyped-defs, but I'm not sure if that actually changes
> the return type of untyped functions from Any to an inferred type. I
> kind of doubt it.

Well, but Any doesn’t fit into QMPResponse, so there should be an error
reported somewhere.

>> (--strict seems, well, overly strict?  Like not allowing generics, I
>> don’t see why.  Or I suppose for the time being we want to allow untyped
>> definitions, as long as they don’t break type assertions such as it kind
>> of does here...?)
> 
> At least, --strict does actually complain about this one because Any
> isn't good enough any more (it includes --warn-return-any):

Hm, yes, but we’re not at a point where it’s really feasible to enable
--strict...

> iotests.py:560: warning: Returning Any from function declared to return 
> "Dict[str, Any]"
> iotests.py:560: error: Call to untyped function "qmp_log" in typed context
> iotests.py:562: warning: Returning Any from function declared to return 
> "Dict[str, Any]"
> 
> Not sure why you think it doesn't allow generics? I never had problems
> with that, even in my Python museum. :-)

I thought --disallow-any-generics would mean that.  But I suppose mypy
understands a “generic” to be something else than I do, as John
described... *shrug*

Max

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