| Message ID | 20200922211313.4082880-8-jsnow@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | qapi: static typing conversion, pt2 | expand |
On Tue, Sep 22, 2020 at 05:13:04PM -0400, John Snow wrote: > 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". > > We don't need to assert that something is a str if we've already checked > that it is -- use a cast instead for these cases. > > Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com> -- Eduardo
On Tue, Sep 22, 2020 at 05:13:04PM -0400, John Snow wrote: > 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". > > We don't need to assert that something is a str if we've already checked > that it is -- use a cast instead for these cases. > > Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Cleber Rosa <crosa@redhat.com>
diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py index 633f9b9172..4a3352a2bd 100644 --- a/scripts/qapi/expr.py +++ b/scripts/qapi/expr.py @@ -15,7 +15,11 @@ # See the COPYING file in the top-level directory. import re -from typing import MutableMapping, Optional +from typing import ( + MutableMapping, + Optional, + cast, +) from .common import c_name from .error import QAPISemError @@ -225,7 +229,7 @@ def check_enum(expr, info): def check_struct(expr, info): - name = expr['struct'] + name = cast(str, expr['struct']) # Asserted in check_exprs members = expr['data'] check_type(members, info, "'data'", allow_dict=name) @@ -233,7 +237,7 @@ def check_struct(expr, info): def check_union(expr, info): - name = expr['union'] + name = cast(str, expr['union']) # Asserted in check_exprs base = expr.get('base') discriminator = expr.get('discriminator') members = expr['data'] @@ -330,7 +334,7 @@ def check_exprs(exprs): else: raise QAPISemError(info, "expression is missing metatype") - name = expr[meta] + name = cast(str, expr[meta]) # asserted right below: check_name_is_str(name, info, "'%s'" % meta) info.set_defn(meta, name) check_defn_name_str(name, info, meta)
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". We don't need to assert that something is a str if we've already checked that it is -- use a cast instead for these cases. Signed-off-by: John Snow <jsnow@redhat.com> --- scripts/qapi/expr.py | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)