aio-libs / multidict / 34591249647

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Build Type

push

github

Committed by web-flow

Commit Message

Implement tp_vectorcall for MultiDict, CIMultiDict and their proxies (#1436)

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## What do these changes do?

`MultiDict(...)`, `CIMultiDict(...)`, `MultiDictProxy(...)` and
`CIMultiDictProxy(...)` now go through a dedicated `tp_vectorcall`
function in the C extension instead of the classic `tp_new`/`tp_init`
pair, avoiding the positional-args tuple and keyword-args dict that
`type.__call__()` otherwise builds for every construction call. The new
path reuses the same `md_init()`/`md_update_from_*()` primitives as the
existing constructors, so behaviour is unchanged.

Since the object under construction is freshly allocated and not yet
reachable from any other thread, only an existing multidict, proxy, or
plain dict argument needs a critical section during construction, not
`self`.

The pure-Python implementation is unaffected: there is no equivalent
C-level calling protocol to opt into there, so no change was needed on
that side.

## Are there changes in behavior for the user?

No. Construction is faster in the common case; results, error messages,
and subclassing behaviour (a `__new__`/`__init__` override in a Python
subclass still runs, since the fast path is not inherited by subclasses)
are unchanged.

## Is it a substantial burden for the maintainers to support this?

No. The new code is a self-contained addition that shares its core logic
with the existing constructors rather than duplicating it, and does not
change any existing code paths.

## Related issue number

N/A

## Checklist

- [x] I think the code is well written
- [x] Unit tests for the changes exist
- [x] Documentation reflects the changes
- [ ] If you provide code modification, please add yourself to
`CONTRIBUTORS.txt`
- [x] Add a new news fragment into the `CHANGES/` folder
- [x] `make doc-spelling` passes and any new technical words are added
to `docs/spelling_wordlist.txt`

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