python typegen output fails to import on python 3.9 and 3.10 (NotRequired, TypeAlias from typing)

[tushardev-365]

Title: python typegen output fails to import on python 3.9 and 3.10 (NotRequired, TypeAlias from typing)

Bug

The python template (src/server/templates/python.ts) generates this import block:

from typing import (
    Annotated,
    Any,
    List,
    Literal,
    NotRequired,
    Optional,
    TypeAlias,
    TypedDict,
)

typing.NotRequired only exists since python 3.11 and typing.TypeAlias since 3.10, so the generated file crashes on import for anyone on 3.9 or 3.10:

ImportError: cannot import name 'NotRequired' from 'typing'

supabase-py supports python >= 3.9, so the generated types are unusable on two supported versions. Hit this on python 3.10.11 with types generated by supabase gen types --lang=python --local (CLI 2.109.1) while following https://supabase.com/docs/guides/api/rest/generating-python-types.

Suggested fix

Import both names from typing_extensions instead. The generated code already depends on pydantic, and pydantic depends on typing_extensions, so this adds no new requirement for users:

from typing import Annotated, Any, List, Literal, Optional, TypedDict
from typing_extensions import NotRequired, TypeAlias

(typing_extensions re-exports these on newer pythons too, so this is safe across all supported versions.)

Happy to send a PR for the template if that helps.

[sornapudisuresh]

I reproduced this on current master and would like to take it.

Verified with clean Python containers:

• Python 3.9: ImportError: cannot import name 'NotRequired' from 'typing'
• Python 3.10: the same NotRequired import failure
• Python 3.11: the current import succeeds

Plan:

1. Move NotRequired and TypeAlias to typing_extensions in the Python type generator while leaving the remaining imports in typing.
2. Update the generated Python inline snapshot / focused generator assertions.
3. Validate generated output imports under Python 3.9, 3.10, and a current Python version with Pydantic installed, then run the TypeScript check and relevant test suite.

I’ll keep this scoped to generated-code compatibility and won’t add a new runtime dependency to postgres-meta itself.

[tushardev-365]

Go for it, glad it reproduced cleanly. If anything in the report is unclear while you build the fix, ping me here, happy to test the PR on 3.9 and 3.10.

[sornapudisuresh]

Thanks @tushardev-365 — the PR is up: #1094

CI is waiting on workflow approval for first-time contributors. Happy to address any feedback once the checks run. Also welcome a 3.9/3.10 smoke test on your side if you still have bandwidth.