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[PULL 08/25] qapi/expr.py: Add casts in a few select cases
From: |
Markus Armbruster |
Subject: |
[PULL 08/25] qapi/expr.py: Add casts in a few select cases |
Date: |
Fri, 30 Apr 2021 13:48:21 +0200 |
From: John Snow <jsnow@redhat.com>
Casts are instructions to the type checker only, they aren't "safe" and
should probably be avoided in general. In this case, when we perform
type checking on a nested structure, the type of each field does not
"stick".
(See PEP 647 for an example of "type narrowing" that does "stick".
It is available in Python 3.10, so we can't use it yet.)
We don't need to assert that something is a str if we've already checked
or asserted that it is -- use a cast instead for these cases.
Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20210421182032.3521476-9-jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
scripts/qapi/expr.py | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py
index 03624bdf3f..f3a4a8536e 100644
--- a/scripts/qapi/expr.py
+++ b/scripts/qapi/expr.py
@@ -15,7 +15,7 @@
# See the COPYING file in the top-level directory.
import re
-from typing import Dict, Optional
+from typing import Dict, Optional, cast
from .common import c_name
from .error import QAPISemError
@@ -261,7 +261,7 @@ def check_enum(expr, info):
def check_struct(expr, info):
- name = expr['struct']
+ name = cast(str, expr['struct']) # Checked in check_exprs
members = expr['data']
check_type(members, info, "'data'", allow_dict=name)
@@ -269,7 +269,7 @@ def check_struct(expr, info):
def check_union(expr, info):
- name = expr['union']
+ name = cast(str, expr['union']) # Checked in check_exprs
base = expr.get('base')
discriminator = expr.get('discriminator')
members = expr['data']
@@ -368,8 +368,8 @@ def check_exprs(exprs):
else:
raise QAPISemError(info, "expression is missing metatype")
- name = expr[meta]
- check_name_is_str(name, info, "'%s'" % meta)
+ check_name_is_str(expr[meta], info, "'%s'" % meta)
+ name = cast(str, expr[meta])
info.set_defn(meta, name)
check_defn_name_str(name, info, meta)
--
2.26.3
- [PULL 00/25] QAPI patches patches for 2021-04-30, Markus Armbruster, 2021/04/30
- [PULL 04/25] qapi/expr.py: constrain incoming expression types, Markus Armbruster, 2021/04/30
- [PULL 03/25] qapi/expr.py: Check for dict instead of OrderedDict, Markus Armbruster, 2021/04/30
- [PULL 08/25] qapi/expr.py: Add casts in a few select cases,
Markus Armbruster <=
- [PULL 13/25] qapi/expr.py: enable pylint checks, Markus Armbruster, 2021/04/30
- [PULL 11/25] qapi/expr.py: Consolidate check_if_str calls in check_if, Markus Armbruster, 2021/04/30
- [PULL 06/25] qapi/expr.py: move string check upwards in check_type, Markus Armbruster, 2021/04/30
- [PULL 12/25] qapi/expr.py: Remove single-letter variable, Markus Armbruster, 2021/04/30
- [PULL 14/25] qapi/expr: Only explicitly prohibit 'Kind' nor 'List' for type names, Markus Armbruster, 2021/04/30
- [PULL 10/25] qapi/expr.py: add type hint annotations, Markus Armbruster, 2021/04/30
- [PULL 09/25] qapi/expr.py: Modify check_keys to accept any Collection, Markus Armbruster, 2021/04/30
- [PULL 01/25] qapi/expr: Comment cleanup, Markus Armbruster, 2021/04/30
- [PULL 16/25] qapi/expr.py: Use tuples instead of lists for static data, Markus Armbruster, 2021/04/30
- [PULL 05/25] qapi/expr.py: Add assertion for union type 'check_dict', Markus Armbruster, 2021/04/30