pytype

A static type analyzer for Python code

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Support

This page lists the Python versions and features supported by the latest version of pytype.

Python Version

Version Analyzes Runs In Issue
2.7 2021.08.03 2020.04.01 #545
3.5 2021.09.09 2020.10.08 #677
3.6 2022.01.05 2022.01.05  
3.7 2023.06.16 2023.06.16  
3.8  
3.9  
3.10  
3.11  
3.12  

Features

Core

Note: pytype supports all language and stdlib features in its supported versions unless noted otherwise. This section lists features that are difficult to type for which pytype has or intends to add custom support.

Feature Supports Issues
Control Flow Analysis (“Type Narrowing”)  
collections.namedtuple  
Dataclasses  
Enums  

Typing

Feature Version Supports Issues
PEP 484 – Type Hints 3.5  
PEP 526 – Syntax for Variable Annotations 3.6  
PEP 561 – Distributing and Packaging Type Information 3.7 #151
PEP 563 – Postponed Evaluation of Annotations 3.7  
PEP 544 – Protocols 3.8  
PEP 586 – Literal Types 3.8  
PEP 589 – TypedDict 3.8  
PEP 591 – Adding a Final Qualifier to Typing 3.8  
PEP 585 – Type Hinting Generics in Standard Collections 3.9  
PEP 593 – Flexible Function and Variable Annotations 3.9  
PEP 604 – Allow Writing Union Types as X | Y 3.10  
PEP 612 – Parameter Specification Variables 3.10 🟡 #786
PEP 613 – Explicit Type Aliases 3.10  
PEP 647 – User-Defined Type Guards 3.10  
PEP 646 – Variadic Generics 3.11 #1525
PEP 655 – Marking individual TypedDict items as required or potentially-missing 3.11  
PEP 673 – Self Type 3.11  
PEP 675 – Arbitrary Literal String Type 3.11 #1552
PEP 681 – Data Class Transforms 3.11 🟡 #1553
PEP 692 – Using TypedDict for more precise **kwargs typing 3.12 #1558
PEP 695 – Type Parameter Syntax 3.12  
PEP 698 – Override Decorator for Static Typing 3.12  
PEP 696 – Type Defaults for Type Parameters 3.13 #1597
PEP 702 – Marking deprecations using the type system 3.13  
PEP 705 – TypedDict: Read-only items 3.13  
PEP 742 – Narrowing types with TypeIs 3.13  
Custom Recursive Types 3.6  
Generic Type Aliases 3.6  
Type Annotation Inheritance 3.6 #81

Non-Standard

This section describes notable non-standard features supported by pytype.

Note: This is not and does not endeavor to be an exhaustive list of the ways in which pytype differs from other Python type checkers. See the Pytype Typing FAQ for more on that topic.

Experimental

This section describes short-lived experimental features that pytype is trialing which aren’t part of the typing spec. In general, experiments are confined to the non-opensourced parts of the Google codebase since they are not supported by other type-checking systems.

By default, experiments have a maximum lifetime of 24 months. They will then either be incorporated into a widely accepted, non-Google only standard or reverted. In either case, our team will be responsible for any remaining code cleanups. The lifetime of an experiment may be extended if forward progress toward adoption by the wider typing community is shown.

Ellipsis Annotation

Third-Party Libraries

Note: This section does not list all third-party libraries that pytype supports, only the ones that are difficult to type for which pytype has or intends to add custom support.

Feature Supports Issues
Attrs  
Chex 🟡 Google-internal
Flax 🟡 Google-internal
Numpy 🟡 Minimal type stub
Tensorflow 🟡 Minimal, Google-internal