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Convert typing tests from reveal_type+comments to assert_type - #1063

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Jun 14, 2026
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Convert typing tests from reveal_type+comments to assert_type#1063
sobolevn merged 5 commits into
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copilot/convert-tests-to-typing-extensions

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Copilot AI commented Jun 13, 2026 •
edited by sobolevn
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Replaces the custom reveal_type + exec'd comment assertion approach with typing_extensions.assert_type, making type assertions first-class errors caught directly by the type checker.

Before:

def check_json_decode_typed_union() -> None:
    o: int | str = msgspec.json.decode(b"", type=int | str)
    reveal_type(o)  # assert "int" in typ and "str" in typ

After:

from typing_extensions import assert_type

def check_json_decode_typed_union() -> None:
    o: int | str = msgspec.json.decode(b"", type=int | str)
    assert_type(o, int | str)

Changes

  • basic_typing_examples.py: Replaced all 162 reveal_type()+comment assertions with assert_type(x, T). Added assert_type and Buffer to typing_extensions imports. Two spots where mypy and pyright genuinely disagree on the inferred type use variable assignments instead:

    • __match_args__ iteration: pyright narrows to Literal['x', 'y'], mypy gives str → _field_str: str = field
    • is_struct_type else-branch on type[Any]: pyright gives Any | type[Any], mypy gives type[Any] → _other_type: type[Any] = other

  • test_mypy.py / test_pyright.py: Replaced the custom output-parsing harness with a simple "run type checker, assert exit code 0" check. assert_type mismatches now surface directly as type checker errors.

Refs #1042

Copilot AI requested a review from sobolevn June 13, 2026 10:56
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sobolevn commented Jun 13, 2026

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I am reviewing this manually now, I've found several problems. This is the first step to change the typing tests for better :)

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sobolevn marked this pull request as ready for review June 13, 2026 11:36
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sobolevn requested a review from provinzkraut June 13, 2026 11:36
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sobolevn commented Jun 13, 2026

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Sorry for using AI-slop, but I did not want to manually convert all this copy-paste code :(
I double checked that every line is correct manually.

@Siyet

Siyet commented Jun 14, 2026

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Thanks @sobolevn! Reviewed and verified the key parts:

  • The Struct.__rich_repr__ narrowing to list[tuple[str, Any]] is correct. Struct_rich_repr in _core.c builds a list of PyTuple_Pack(2, field, val), and at runtime P(1, "foo").__rich_repr__() returns [('x', 1), ('y', 'foo')]. The old Iterable[Any | tuple[Any] | tuple[str, Any] | tuple[str, Any, Any]] union was both too broad and inaccurate.
  • The assert_type conversions and the simplified exit-code-0 harness look good, and the two mypy/pyright divergence workarounds are sound.

One non-blocking nit: Meta.__rich_repr__ is still typed Iterable[tuple[str, Any]], but at runtime it also returns a list (Meta(ge=1).__rich_repr__() -> [('ge', 1)], built the same way in Meta_rich_repr). Want to narrow it to list[tuple[str, Any]] here too for consistency? Happy to merge as-is if you'd rather keep this PR focused.

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sobolevn enabled auto-merge June 14, 2026 16:58
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sobolevn added this pull request to the merge queue Jun 14, 2026
Merged via the queue into main with commit 49d5348 Jun 14, 2026
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sobolevn deleted the copilot/convert-tests-to-typing-extensions branch June 14, 2026 16:59
@Siyet Siyet mentioned this pull request Jun 15, 2026
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@Siyet Siyet mentioned this pull request Sep 20, 2026
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pull Bot pushed a commit to Mu-L/msgspec that referenced this pull request Sep 24, 2026
@Siyet
Record the merged changes missing from the changelog (msgspec#1195)
6264d46 
The changelog has not been updated since the `## Version 0.22.0` section
was written, and that release was never published: PyPI still serves
0.21.1, and the tag and GitHub release were removed after the failed
run.

Adds ten entries under `## Unreleased`, covering twelve pull requests
merged after 2026-08-11. That is where they belong while the release
date is unknown. The entry for msgspec#1165 moves there from the 0.22.0 section
for the same reason, since its fix was merged on 2026-09-05. msgspec#1063 and
msgspec#1064 are added to the aggregated type stub line in the 0.22.0 section:
two June pull requests that edit shipped `.pyi` files and were missing
entirely.

A second commit extends `scripts/release_github.py` to substitute
`{issue}` references as well as `{pr}` ones, so they stop reaching the
release body as literal markup.

---------

Co-authored-by: Tseluiko Aleksandr <[email protected]>
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