Configure Pyrefly

[s2t2]

Internally at Google we have changed to use Pyrefly instead of pytype.

https://pyrefly.org/

https://pyrefly.org/en/docs/error-kinds/

We should update the tooling in this repository to match.

This is the blessed "pyrefly.toml" config file to help OSS repos match internal Google formatting

# This is a pyrefly config for the use of OSS developers at Google.
# This configuration is intended to provide a closest configuration to the
# current g3 pyrefly.
python-version = "3.13"

# set the directory Pyrefly will search for files to type check
project-includes = []

# manually set the `sys.platform` Pyrefly will assume when type checking
python-platform = "linux"

# LINT.IfChange(pyrefly_oss_config)
infer-with-first-use = false
check-unannotated-defs = true
infer-return-types = "never"

# a table mapping error codes to an `is-enabled` boolean
[errors]
implicit-import = false
unused-coroutine = false
protocol-implicitly-defined-attribute = false
redundant-condition = false
unreachable = false
unsafe-overlap = false
redefinition = false
bad-dunder-all = false
bad-override-mutable-attribute = false
bad-override-param-name = false
abstract-method-call = false
# LINT.ThenChange(
#  [//depot/google3/third_party/pyrefly/pyrefly/lib/commands/util.rs:pytype_non_parity_errors](https://source.corp.google.com/piper///depot/google3/third_party/pyrefly/pyrefly/lib/commands/util.rs?q=%22LINT.IfChange%28pytype_non_parity_errors%29%22+case:yes),
#  [//depot/google3/third_party/pyrefly/pyrefly/lib/commands/util.rs:pytype_non_parity_command_line_arguments](https://source.corp.google.com/piper///depot/google3/third_party/pyrefly/pyrefly/lib/commands/util.rs?q=%22LINT.IfChange%28pytype_non_parity_command_line_arguments%29%22+case:yes)
#)

We also want to run pyrefly checks during pre-commit hooks and the CI build, and update documentation accordingly.

[SankeerthNara]

Could you assign this to me

[yash2006kr]

Hi @s2t2, I’d like to work on this if it’s still available.

I can add the Pyrefly config from the issue, wire it into the existing lint/type-check tooling, update docs/CI if needed, and keep the PR small. Please let me know if you’d prefer I wait because someone else is already taking it.

[s2t2]

We had #175 going but we definitely want CI integration and pre-commit hooks, and updated documentation (I just updated the issue description to reflect this). Feel free to jump in.

[yash2006kr]

Hi @s2t2, thanks again for confirming this issue was open to work on.

I opened #181 with the requested Pyrefly setup: CI integration, a pre-commit hook, and updated contributing docs. CLA and the GitHub Actions scan are passing now.

The earlier Python CI failure was from Markdown formatting in docs/contributing.md; I pushed a fix for that, but it looks like the Python CI has not rerun on the latest commit yet, possibly because it needs maintainer approval for a forked PR.

Could you please take a look when you get time, and rerun/approve CI if needed? Thanks!

[s2t2]

Nice @yash2006kr.

Let's leave this issue open for now until after the upcoming sync out when we will hopefully fix all the existing pyrefly issues, at which time we can come back and enable strictness of the pyrefly checks, and then close this issue.