Improve types beyond what typeshed has.

- Typeshed has argument types as `bytes` to substitute for buffers since buffers didn't have a representation in the type system for a long time. Now that `collections.abc.Buffer` exists, there's a better alternative.
 - This means that memoryview, bytarray, etc. won't show up as type-checker errors when given as inputs.
- Tests actually type-check as a result. No changes to logic were made, just type annotations.
- TODO: Consider upstreaming to typeshed?

Reference material:
- https://docs.python.org/3/library/typing.html#typing.ByteString
- https://docs.python.org/3/library/collections.abc.html#collections.abc.Buffer
- https://peps.python.org/pep-0688
 - "No special meaning for bytes" mentions why these were annotated with `bytes` before.
- https://typing.readthedocs.io/en/latest/source/modernizing.html#typing-bytestring

audioop/__init__.pyi

@@ -1,32 +1,33 @@
-from typing_extensions import TypeAlias
+from collections.abc import Buffer
+from typing import TypeAlias
 
 _AdpcmState: TypeAlias = tuple[int, int]
 _RatecvState: TypeAlias = tuple[int, tuple[tuple[int, int], ...]]
 
 class error(Exception): ...
 
-def add(fragment1: bytes, fragment2: bytes, width: int, /) -> bytes: ...
-def adpcm2lin(fragment: bytes, width: int, state: _AdpcmState | None, /) -> tuple[bytes, _AdpcmState]: ...
-def alaw2lin(fragment: bytes, width: int, /) -> bytes: ...
-def avg(fragment: bytes, width: int, /) -> int: ...
-def avgpp(fragment: bytes, width: int, /) -> int: ...
-def bias(fragment: bytes, width: int, bias: int, /) -> bytes: ...
-def byteswap(fragment: bytes, width: int, /) -> bytes: ...
-def cross(fragment: bytes, width: int, /) -> int: ...
-def findfactor(fragment: bytes, reference: bytes, /) -> float: ...
-def findfit(fragment: bytes, reference: bytes, /) -> tuple[int, float]: ...
-def findmax(fragment: bytes, length: int, /) -> int: ...
-def getsample(fragment: bytes, width: int, index: int, /) -> int: ...
-def lin2adpcm(fragment: bytes, width: int, state: _AdpcmState | None, /) -> tuple[bytes, _AdpcmState]: ...
-def lin2alaw(fragment: bytes, width: int, /) -> bytes: ...
-def lin2lin(fragment: bytes, width: int, newwidth: int, /) -> bytes: ...
-def lin2ulaw(fragment: bytes, width: int, /) -> bytes: ...
-def max(fragment: bytes, width: int, /) -> int: ...
-def maxpp(fragment: bytes, width: int, /) -> int: ...
-def minmax(fragment: bytes, width: int, /) -> tuple[int, int]: ...
-def mul(fragment: bytes, width: int, factor: float, /) -> bytes: ...
+def add(fragment1: Buffer, fragment2: Buffer, width: int, /) -> bytes: ...
+def adpcm2lin(fragment: Buffer, width: int, state: _AdpcmState | None, /) -> tuple[bytes, _AdpcmState]: ...
+def alaw2lin(fragment: Buffer, width: int, /) -> bytes: ...
+def avg(fragment: Buffer, width: int, /) -> int: ...
+def avgpp(fragment: Buffer, width: int, /) -> int: ...
+def bias(fragment: Buffer, width: int, bias: int, /) -> bytes: ...
+def byteswap(fragment: Buffer, width: int, /) -> bytes: ...
+def cross(fragment: Buffer, width: int, /) -> int: ...
+def findfactor(fragment: Buffer, reference: Buffer, /) -> float: ...
+def findfit(fragment: Buffer, reference: Buffer, /) -> tuple[int, float]: ...
+def findmax(fragment: Buffer, length: int, /) -> int: ...
+def getsample(fragment: Buffer, width: int, index: int, /) -> int: ...
+def lin2adpcm(fragment: Buffer, width: int, state: _AdpcmState | None, /) -> tuple[bytes, _AdpcmState]: ...
+def lin2alaw(fragment: Buffer, width: int, /) -> bytes: ...
+def lin2lin(fragment: Buffer, width: int, newwidth: int, /) -> bytes: ...
+def lin2ulaw(fragment: Buffer, width: int, /) -> bytes: ...
+def max(fragment: Buffer, width: int, /) -> int: ...
+def maxpp(fragment: Buffer, width: int, /) -> int: ...
+def minmax(fragment: Buffer, width: int, /) -> tuple[int, int]: ...
+def mul(fragment: Buffer, width: int, factor: float, /) -> bytes: ...
 def ratecv(
-    fragment: bytes,
+    fragment: Buffer,
     width: int,
     nchannels: int,
     inrate: int,
@@ -36,9 +37,9 @@ def ratecv(
     weightB: int = 0,
     /,
 ) -> tuple[bytes, _RatecvState]: ...
-def reverse(fragment: bytes, width: int, /) -> bytes: ...
-def rms(fragment: bytes, width: int, /) -> int: ...
-def tomono(fragment: bytes, width: int, lfactor: float, rfactor: float, /) -> bytes: ...
-def tostereo(fragment: bytes, width: int, lfactor: float, rfactor: float, /) -> bytes: ...
-def ulaw2lin(fragment: bytes, width: int, /) -> bytes: ...
+def reverse(fragment: Buffer, width: int, /) -> bytes: ...
+def rms(fragment: Buffer, width: int, /) -> int: ...
+def tomono(fragment: Buffer, width: int, lfactor: float, rfactor: float, /) -> bytes: ...
+def tostereo(fragment: Buffer, width: int, lfactor: float, rfactor: float, /) -> bytes: ...
+def ulaw2lin(fragment: Buffer, width: int, /) -> bytes: ...
 # pyright: ignore [reportShadowedImports]

pyproject.toml

@@ -28,10 +28,11 @@ audioop = ["*.c", "*.h"]
 
 [tool.pyright]
 include = ["audioop"]
-ignore = ["audioop/__init__.py", "tests"]
+ignore = [
+    "audioop/__init__.py", # Pyright can't see the shared object being imported from.
+]
 pythonVersion = "3.13"
 typeCheckingMode = "strict"
 
 reportPrivateUsage = "none"
-reportMissingTypeStubs = "none"
 reportUnnecessaryTypeIgnoreComment = "warning"

tests/test_audioop.py

@@ -1,16 +1,19 @@
 import sys
 import unittest
-import audioop
+import audioop  # pyright: ignore[reportShadowedImports]
+from collections.abc import Callable
 
 
-def pack(width, data):
+def pack(width: int, data: tuple[int, ...]) -> bytes:
     return b''.join(v.to_bytes(width, sys.byteorder, signed=True) for v in data)
 
-def unpack(width, data):
+def unpack(width: int, data: bytes) -> list[int]:
     return [int.from_bytes(data[i: i + width], sys.byteorder, signed=True)
             for i in range(0, len(data), width)]
 
-packs = {w: (lambda *data, width=w: pack(width, data)) for w in (1, 2, 3, 4)}
+packs: dict[int, Callable[[*tuple[int, ...]], bytes]] = {
+    w: (lambda *data, width=w: pack(width, data)) for w in (1, 2, 3, 4)
+}
 maxvalues = {w: (1 << (8 * w - 1)) - 1 for w in (1, 2, 3, 4)}
 minvalues = {w: -1 << (8 * w - 1) for w in (1, 2, 3, 4)}