Re: [PATCH v3 13/16] qapi/expr.py: Modify check_keys to accept any Collection

[Markus Armbruster <armbru@redhat.com>]

John Snow <jsnow@redhat.com> writes:

> This is a minor adjustment that allows the 'required' and 'optional'
> keys fields to take a default value of an empty, immutable sequence (the
> empty tuple).

Quite marginal, but simple enough for me not to say no to it.

> This reveals a quirk of this function, which is that "a + b" is
> list-specific behavior. We can accept a wider variety of types if we
> avoid that behavior. Using Collection allows us to accept things like
> lists, tuples, sets, and so on.
>
> (Iterable would also have worked, but Iterable also includes things like
> generator expressions which are consumed upon iteration, which would
> require a rewrite to make sure that each input was only traversed once.)

Totally not worth it now :)

> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>  scripts/qapi/expr.py | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py
> index 2b96bec722f..0b841f292d7 100644
> --- a/scripts/qapi/expr.py
> +++ b/scripts/qapi/expr.py
> @@ -33,6 +33,7 @@
>  
>  import re
>  from typing import (
> +    Collection,
>      Iterable,
>      List,
>      MutableMapping,
> @@ -133,8 +134,8 @@ def check_defn_name_str(name: str, info: QAPISourceInfo, meta: str) -> None:
>  def check_keys(value: _JSObject,
>                 info: QAPISourceInfo,
>                 source: str,
> -               required: List[str],
> -               optional: List[str]) -> None:
> +               required: Collection[str] = (),
> +               optional: Collection[str] = ()) -> None:
>      """
>      Ensures an object has a specific set of keys. [Const]
>  

Any particular reason not to squash this part into PATCH 08?  Oh, I
figure it's because it requires the next hunk, and squashing that one
would kill PATCH 08's "This commit *only* adds annotations."  What about
putting the next hunk before 08, and squash the remainder?

> @@ -155,7 +156,7 @@ def pprint(elems: Iterable[str]) -> str:
>              "%s misses key%s %s"
>              % (source, 's' if len(missing) > 1 else '',
>                 pprint(missing)))
> -    allowed = set(required + optional)
> +    allowed = set(required) | set(optional)
>      unknown = set(value) - allowed
>      if unknown:
>          raise QAPISemError(