chore(type-check): switch static type checking from ty to pyrefly

.github/workflows/tests.yml

@@ -62,7 +62,7 @@ jobs:
           make init-uv
           make install
 
-      - name: Type checking with ty
+      - name: Type checking with Pyrefly
         run: make type
 
   test:

.pre-commit-config.yaml

@@ -25,9 +25,14 @@ repos:
     - id: ruff-format
     - id: ruff
 
-# ty
-# Note: ty pre-commit hook not yet available (see https://github.com/astral-sh/ty/issues/269)
-# Type checking is handled via prek or make type
+# pyrefly
+- repo: https://github.com/facebook/pyrefly-pre-commit
+  rev: 1.2.0  # pre-commit hook version, not the pyrefly version (that comes from pyproject.toml)
+  hooks:
+    - id: pyrefly-check
+      name: pyrefly
+      pass_filenames: false
+      language: system  # use the project's own pyrefly install so versions stay in sync with pyproject.toml
 
 # sqlfluff
 - repo: https://github.com/sqlfluff/sqlfluff

Makefile

@@ -48,7 +48,7 @@ lint-sql:
 	uv run sqlfluff lint .
 
 type:
-	uv run ty check
+	uv run pyrefly check
 
 test:
 	uv run pytest -vv -m "not df"

README.md

@@ -33,14 +33,14 @@ uv run prek run
 # uv run prek run <hook>
 uv run prek run ruff-format
 uv run prek run ruff
-uv run prek run ty
+uv run prek run pyrefly-check
 
 # To run a particular prek hook against all files (staged and unstaged, before committing):
 uv run prek run ruff --all-files
 
 # run checks regardless of git status
 uv run ruff format --check src
-uv run ty src
+uv run pyrefly check
 uv run ruff src
 ```
 
@@ -99,16 +99,16 @@ The checks contained in this repo include (in the order in which they run):
 * Various checkers and formatters to verify valid file types, file size, and end of line and end of file whitespace/newlines
 * `ruff format` applies standard code style formatting (just like `black`, but faster)
 * `ruff` checks code for "lint"
-* `ty` is used for static type checking
+* `pyrefly` is used for static type checking
 * `sqlfluff` checks and fixes sql formatting and linting
 * `uv` checks on valid and aligned pyproject.toml and uv.lock files
 * `commitlint` enforces commit message conforms to [conventional commit](https://www.conventionalcommits.org/en/v1.0.0/) format
 
 If you want `ruff format` to ignore a particular section of code, you can add the comments `# fmt: off` and `# fmt: on` before and after the respective block of code (same as you would if using `black`).
 * https://stackoverflow.com/a/58584557
 
-If you want `ty` to ignore a particular line of code, you can add the comment `# type: ignore` to the end of that line.
-If `# type: ignore` is added to the very top of a file, `ty` will ignore the entire file.
+If you want `pyrefly` to ignore a particular line of code, you can add the comment `# pyrefly: ignore` to the end of
+that line (`# type: ignore` is also respected).
 
 If you absolutely must commit without adhering to the prek hooks, then you can use `git commit -n ...` where `-n` is shorthand for `--no-verify`.
 

pyproject.toml

@@ -28,12 +28,12 @@ dev = [
     "mkdocstrings[python] >=0.25.2,<1",
     "nox >=2024.4.15,<2025",
     "prek >=0.1.0,<1",
+    "pyrefly >=1.2.0,<2",
     "pytest >=8.3.2,<9",
     "pytest-cov >=5.0.0,<6",
     "python-semantic-release >=10.0.0,<11",
     "ruff >=0.6.2,<1",
     "sqlfluff >=3.1.1,<4",
-    "ty >=0.0.11,<1",
 ]
 
 
@@ -53,10 +53,11 @@ fail_under = 70
 show_missing = true
 
 
-####
-# Ty
-####
-[tool.ty]
+#########
+# Pyrefly
+#########
+[tool.pyrefly]
+project-includes = ["src", "tests", "noxfile.py"]
 
 
 ######

src/sample/placeholder.py

@@ -7,7 +7,7 @@
 
 import sample
 
-MODULE_DIR = Path(sample.__file__).resolve().parent  # type: ignore
+MODULE_DIR = Path(sample.__file__).resolve().parent
 SQL_DIR = MODULE_DIR / "sql"