From: John Snow <email@example.com> To: Markus Armbruster <firstname.lastname@example.org> Cc: Michael Roth <email@example.com>, firstname.lastname@example.org, Eduardo Habkost <email@example.com>, Cleber Rosa <firstname.lastname@example.org> Subject: Re: [PATCH v4 05/19] qapi/expr.py: constrain incoming expression types Date: Fri, 26 Mar 2021 13:12:49 -0400 [thread overview] Message-ID: <email@example.com> (raw) In-Reply-To: <firstname.lastname@example.org> On 3/26/21 1:40 AM, Markus Armbruster wrote: > John Snow <email@example.com> writes: > >> On 3/25/21 10:04 AM, Markus Armbruster wrote: >>> John Snow <firstname.lastname@example.org> writes: >>> >>>> mypy does not know the types of values stored in Dicts that masquerade >>>> as objects. Help the type checker out by constraining the type. >>>> >>>> Signed-off-by: John Snow <email@example.com> >>>> --- >>>> scripts/qapi/expr.py | 26 +++++++++++++++++++++++--- >>>> 1 file changed, 23 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py >>>> index b4bbcd54c0..b75c85c160 100644 >>>> --- a/scripts/qapi/expr.py >>>> +++ b/scripts/qapi/expr.py >>>> @@ -15,9 +15,18 @@ >>>> # See the COPYING file in the top-level directory. >>>> >>>> import re >>>> +from typing import Dict, Optional >>>> >>>> from .common import c_name >>>> from .error import QAPISemError >>>> +from .parser import QAPIDoc >>>> +from .source import QAPISourceInfo >>>> + >>>> + >>>> +# Deserialized JSON objects as returned by the parser; >>>> +# The values of this mapping are not necessary to exhaustively type >>> >>> Not necessary and also not practical with current mypy. Correct? >> >> Neither necessary nor practical. Typing as 'object' guarantees that >> these values will never be used in a manner not supported by all python >> objects. Mypy does not complain, so we know that we don't misuse the type. >> >> This is helpful for proving the validity of the expr.py validator >> itself: we know that we are not forgetting to perform type narrowing and >> using the value contained therein inappropriately. >> >> Adding a more exhaustive typing here is impractical (for reasons we >> learned during introspect.py), but also provides no benefit to the >> static analysis here anyway. >> >> (None of the functions written here *assume* the shape of the structure, >> so there are no functions that benefit from having a more laboriously >> specified type.) >> >> If the comment needs more work, suggest away -- I tried to follow our >> last discussion here as best as I was able. > > "Needs more work" sounds like "inadequate", which isn't the case. > > The comment focuses on what we need from mypy here. We may or may not > want to hint at the other aspect: what mypy can provide. > >>>> +# here, because the purpose of this module is to interrogate that type. >>>> +_JSONObject = Dict[str, object] > [...] > > If we want to, maybe: > > # Deserialized JSON objects as returned by the parser. > # The values of this mapping are not necessary to exhaustively type > # here (and also not practical as long as mypy lacks recursive > # types), because the purpose of this module is to interrogate that > # type. > > Thoughts? > If it occurs to you to want the extra explanation, I won't say no to it. I will fold it in. --js
next prev parent reply other threads:[~2021-03-26 17:13 UTC|newest] Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-25 6:03 [PATCH v4 00/19] qapi: static typing conversion, pt3 John Snow 2021-03-25 6:03 ` [PATCH v4 01/19] qapi/expr: Comment cleanup John Snow 2021-03-25 15:41 ` Markus Armbruster 2021-03-25 20:06 ` John Snow 2021-03-25 6:03 ` [PATCH v4 02/19] flake8: Enforce shorter line length for comments and docstrings John Snow 2021-03-25 15:21 ` Markus Armbruster 2021-03-25 20:20 ` John Snow 2021-03-26 6:26 ` Markus Armbruster 2021-03-26 16:30 ` John Snow 2021-03-26 16:44 ` Peter Maydell 2021-04-08 8:32 ` Markus Armbruster 2021-04-08 8:58 ` Daniel P. Berrangé 2021-04-09 9:33 ` Markus Armbruster 2021-04-09 17:08 ` John Snow 2021-04-08 8:35 ` Markus Armbruster 2021-04-16 12:44 ` Markus Armbruster 2021-04-16 20:25 ` John Snow 2021-04-17 10:52 ` Markus Armbruster 2021-04-20 18:06 ` John Snow 2021-03-25 6:03 ` [PATCH v4 03/19] qapi/expr.py: Remove 'info' argument from nested check_if_str John Snow 2021-03-25 6:03 ` [PATCH v4 04/19] qapi/expr.py: Check for dict instead of OrderedDict John Snow 2021-03-25 6:03 ` [PATCH v4 05/19] qapi/expr.py: constrain incoming expression types John Snow 2021-03-25 14:04 ` Markus Armbruster 2021-03-25 20:48 ` John Snow 2021-03-26 5:40 ` Markus Armbruster 2021-03-26 17:12 ` John Snow [this message] 2021-03-25 6:03 ` [PATCH v4 06/19] qapi/expr.py: Add assertion for union type 'check_dict' John Snow 2021-03-25 6:03 ` [PATCH v4 07/19] qapi/expr.py: move string check upwards in check_type John Snow 2021-03-25 6:03 ` [PATCH v4 08/19] qapi: add tests for invalid 'data' field type John Snow 2021-03-25 14:24 ` Markus Armbruster 2021-03-25 6:03 ` [PATCH v4 09/19] qapi/expr.py: Check type of 'data' member John Snow 2021-03-25 14:26 ` Markus Armbruster 2021-03-25 21:04 ` John Snow 2021-03-25 6:03 ` [PATCH v4 10/19] qapi/expr.py: Add casts in a few select cases John Snow 2021-03-25 14:33 ` Markus Armbruster 2021-03-25 23:32 ` John Snow 2021-03-25 6:03 ` [PATCH v4 11/19] qapi/expr.py: Modify check_keys to accept any Collection John Snow 2021-03-25 14:45 ` Markus Armbruster 2021-03-25 23:37 ` John Snow 2021-03-25 6:03 ` [PATCH v4 12/19] qapi/expr.py: add type hint annotations John Snow 2021-03-25 6:03 ` [PATCH v4 13/19] qapi/expr.py: Consolidate check_if_str calls in check_if John Snow 2021-03-25 15:15 ` Markus Armbruster 2021-03-26 0:07 ` John Snow 2021-03-25 6:03 ` [PATCH v4 14/19] qapi/expr.py: Remove single-letter variable John Snow 2021-03-25 6:03 ` [PATCH v4 15/19] qapi/expr.py: enable pylint checks John Snow 2021-03-25 6:03 ` [PATCH v4 16/19] qapi/expr.py: Add docstrings John Snow 2021-04-14 15:04 ` Markus Armbruster 2021-04-17 1:00 ` John Snow 2021-04-17 13:18 ` Markus Armbruster 2021-04-21 1:27 ` John Snow 2021-04-21 13:58 ` Markus Armbruster 2021-04-21 18:20 ` John Snow 2021-03-25 6:03 ` [PATCH v4 17/19] qapi/expr.py: Use tuples instead of lists for static data John Snow 2021-03-25 15:19 ` Markus Armbruster 2021-03-25 6:03 ` [PATCH v4 18/19] qapi/expr.py: move related checks inside check_xxx functions John Snow 2021-03-25 6:03 ` [PATCH v4 19/19] qapi/expr.py: Use an expression checker dispatch table John Snow 2021-03-25 15:46 ` [PATCH v4 00/19] qapi: static typing conversion, pt3 Markus Armbruster 2021-03-26 0:40 ` John Snow 2021-03-26 18:01 ` John Snow
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