python / python/mypy

TypedDict annotation keys should considered Literals

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#16,821 2 comments 5 reactions 0 assignees View on GitHub

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feature
Dominant language
Python
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Description

Feature

TypedDict.__annotations__.keys(), required_keys and optional_keys should evaluate to Sequence of Literals

Pitch

See https://github.com/python/mypy/issues/16813 for an example why this is useful.
In general working with TypedDicts in for loop this helps a lot reducing duplicate code / keys.

Probably #16820 and #16819 have to be finished before this becomes useful.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reviewing the TypedDict behavior described in the issue, along with the examples in mypy#16813 and the dependencies on #16819 and #16820. Define how annotations.keys(), required_keys, and optional_keys should evaluate as sequences of Literals, then verify the behavior across the referenced TypedDict iteration cases.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
devtools
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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