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base repository: vercel/python-typemap
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  • 4 commits
  • 20 files changed
  • 1 contributor

Commits on Apr 17, 2026

  1. Replace *[comprehension] with *Map(comprehension) for type-level iter… 

    …ation

Map is a new operator that wraps the comprehension and will eventually
support different semantics (e.g. propagating Any). For now it behaves
identically to the bare list comprehension. Mypy tests for files that
use Map are xfailed until the stubs are updated.
    @msullivan
    msullivan committed Apr 17, 2026
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  2. Collapse tuple[*Map(... for _ in Iter[Any])] to Any 

    Iter[Any] now returns a generator that raises IterAnyError on first
__next__ (not __iter__, which CPython calls eagerly when constructing a
genexpr -- before Map can wrap it). Map catches IterAnyError via
`yield from` and yields a _UnpackAny sentinel, which callers of
_eval_args short-circuit into typing.Any.
    @msullivan
    msullivan committed Apr 17, 2026
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  3. Defer Map iteration from __iter__ to the evaluator 

    Map.__iter__ now just yields an (_UnpackedMap, _UnpackedMapEnd) pair; the
evaluator drives the wrapped generator inside _eval_args, catches
IterAnyError there, and emits _UnpackAny. The trailing sentinel keeps
Union[*Map(...)] from collapsing to a single arg before _eval_union can
see it. IterAnyError is now a TypeMapError subclass, living entirely
inside the evaluator.

_eval_args iterates the generator one value at a time so that nested
genexprs closing over the outer iteration variable don't all see its
final value. _eval_union now routes through _eval_args too.
    @msullivan
    msullivan committed Apr 17, 2026
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  4. Extract _eval_and_append helper in _eval_args 

    Both the _UnpackedMap branch and the plain-arg branch did the same
eval-and-unpack dance; pull it out.
    @msullivan
    msullivan committed Apr 17, 2026
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