John Snow <jsnow@redhat.com> writes:
On 4/25/21 3:27 AM, Markus Armbruster wrote:
John Snow <jsnow@redhat.com> writes:
The single quote token implies the value is a string. Assert this to be
the case.
Signed-off-by: John Snow <jsnow@redhat.com>
---
scripts/qapi/parser.py | 2 ++
1 file changed, 2 insertions(+)
diff --git a/scripts/qapi/parser.py b/scripts/qapi/parser.py
index 6b443b1247e..8d1fe0ddda5 100644
--- a/scripts/qapi/parser.py
+++ b/scripts/qapi/parser.py
@@ -246,6 +246,8 @@ def get_members(self):
raise QAPIParseError(self, "expected string or '}'")
while True:
key = self.val
+ assert isinstance(key, str) # Guaranteed by tok == "'"
+
self.accept()
if self.tok != ':':
raise QAPIParseError(self, "expected ':'")
The assertion is correct, but I wonder why mypy needs it. Can you help?
The lexer value can also be True/False (Maybe None? I forget) based on
Yes, None for tokens like '{'.
the Token returned. Here, since the token was the single quote, we know
that value must be a string.
Mypy has no insight into the correlation between the Token itself and
the token value, because that relationship is not expressed via the type
system.
I understand that mypy can't prove implications like if self.tok == "'",
then self.val is a str.
What I'm curious about is why key needs to be known to be str here.
Hmm, is it so return expr type-checks once you add -> OrderedDict[str,
object] to the function?