Move to pyright and fix type errors

Author: callumforrester

pyproject.toml

@@ -11,11 +11,7 @@ classifiers = [
     "Programming Language :: Python :: 3.11",
 ]
 description = "Specify step and flyscan paths in a serializable, efficient and Pythonic way"
-dependencies = [
-    "numpy>=2",
-    "click>=8.1",
-    "pydantic>=2.0",
-]
+dependencies = ["numpy>=2", "click>=8.1", "pydantic>=2.0"]
 dynamic = ["version"]
 license.file = "LICENSE"
 readme = "README.md"
@@ -33,11 +29,11 @@ dev = [
     "scanspec[plotting]",
     "scanspec[service]",
     "copier",
-    "mypy",
     "myst-parser",
     "pipdeptree",
     "pre-commit",
     "pydata-sphinx-theme>=0.12",
+    "pyright",
     "pytest",
     "pytest-cov",
     "ruff",
@@ -65,8 +61,9 @@ name = "Tom Cobb"
 [tool.setuptools_scm]
 write_to = "src/scanspec/_version.py"
 
-[tool.mypy]
-ignore_missing_imports = true # Ignore missing stubs in imported modules
+[tool.pyright]
+# strict = ["src", "tests"]
+reportMissingImports = false # Ignore missing stubs in imported modules
 
 [tool.pytest.ini_options]
 # Run pytest with all our checkers, and don't spam us with massive tracebacks on error
@@ -99,12 +96,12 @@ passenv = *
 allowlist_externals =
     pytest
     pre-commit
-    mypy
+    pyright
     sphinx-build
     sphinx-autobuild
 commands =
     pre-commit: pre-commit run --all-files {posargs}
-    type-checking: mypy src tests {posargs}
+    type-checking: pyright src tests {posargs}
     tests: pytest --cov=scanspec --cov-report term --cov-report xml:cov.xml {posargs}
     docs: sphinx-{posargs:build -E --keep-going} -T docs build/html
 """
@@ -115,14 +112,21 @@ line-length = 88
 
 [tool.ruff.lint]
 extend-select = [
-    "B",  # flake8-bugbear - https://docs.astral.sh/ruff/rules/#flake8-bugbear-b
-    "C4", # flake8-comprehensions - https://docs.astral.sh/ruff/rules/#flake8-comprehensions-c4
-    "E",  # pycodestyle errors - https://docs.astral.sh/ruff/rules/#error-e
-    "F",  # pyflakes rules - https://docs.astral.sh/ruff/rules/#pyflakes-f
-    "W",  # pycodestyle warnings - https://docs.astral.sh/ruff/rules/#warning-w
-    "I",  # isort - https://docs.astral.sh/ruff/rules/#isort-i
-    "UP", # pyupgrade - https://docs.astral.sh/ruff/rules/#pyupgrade-up
+    "B",   # flake8-bugbear - https://docs.astral.sh/ruff/rules/#flake8-bugbear-b
+    "C4",  # flake8-comprehensions - https://docs.astral.sh/ruff/rules/#flake8-comprehensions-c4
+    "E",   # pycodestyle errors - https://docs.astral.sh/ruff/rules/#error-e
+    "F",   # pyflakes rules - https://docs.astral.sh/ruff/rules/#pyflakes-f
+    "W",   # pycodestyle warnings - https://docs.astral.sh/ruff/rules/#warning-w
+    "I",   # isort - https://docs.astral.sh/ruff/rules/#isort-i
+    "UP",  # pyupgrade - https://docs.astral.sh/ruff/rules/#pyupgrade-up
+    "SLF", # self - https://docs.astral.sh/ruff/settings/#lintflake8-self
 ]
 ignore = [
     "B008", # We use function calls in service arguments
 ]
+
+[tool.ruff.lint.per-file-ignores]
+# By default, private member access is allowed in tests
+# See https://github.com/DiamondLightSource/python-copier-template/issues/154
+# Remove this line to forbid private member access in tests
+"tests/**/*" = ["SLF001"]

src/scanspec/cli.py

@@ -1,5 +1,6 @@
 import logging
 import string
+from typing import Callable
 
 import click
 
@@ -25,6 +26,9 @@ def cli(ctx, log_level: str):
 
     # if no command is supplied, print the help message
     if ctx.invoked_subcommand is None:
+        # We need to prove that cli has been converted to a command
+        # by the click decorator to keep pyright happy.
+        assert isinstance(cli, click.Command)
         click.echo(cli.get_help(ctx))
 
 

src/scanspec/core.py

@@ -35,11 +35,14 @@
 
 StrictConfig: ConfigDict = {"extra": "forbid"}
 
+C = TypeVar("C")
+T = TypeVar("T", type, Callable)
+
 
 def discriminated_union_of_subclasses(
-    super_cls: type,
+    super_cls: type[C],
     discriminator: str = "type",
-) -> type:
+) -> type[C]:
     """Add all subclasses of super_cls to a discriminated union.
 
     For all subclasses of super_cls, add a discriminator field to identify
@@ -137,9 +140,6 @@ def get_schema_of_union(cls, source_type: Any, handler: GetCoreSchemaHandler):
     return super_cls
 
 
-T = TypeVar("T", type, Callable)
-
-
 def uses_tagged_union(cls_or_func: T) -> T:
     """
     T = TypeVar("T", type, Callable)
@@ -616,7 +616,7 @@ def consume(self, num: int | None = None) -> Frames[Axis]:
 
     def __len__(self) -> int:
         """Number of frames left in a scan, reduces when `consume` is called."""
-        return self.end_index - self.index
+        return int(self.end_index - self.index)
 
 
 class Midpoints(Generic[Axis]):

src/scanspec/plot.py

@@ -33,7 +33,7 @@ def __init__(self, xs, ys, zs, *args, **kwargs):
     # Added here because of https://github.com/matplotlib/matplotlib/issues/21688
     def do_3d_projection(self, renderer=None):
         xs3d, ys3d, zs3d = self._verts3d
-        xs, ys, zs = proj3d.proj_transform(xs3d, ys3d, zs3d, self.axes.M)
+        xs, ys, zs = proj3d.proj_transform(xs3d, ys3d, zs3d, self.axes.M)  # type: ignore
         self.set_positions((xs[0], ys[0]), (xs[1], ys[1]))
 
         return np.min(zs)
@@ -109,11 +109,17 @@ def plot_spec(spec: Spec[Any], title: str | None = None):
     # Setup axes
     if ndims > 2:
         plt.figure(figsize=(6, 6))
-        plt_axes: Axes3D = plt.axes(projection="3d")
+        plt_axes = plt.axes(projection="3d")
         plt_axes.grid(False)
-        plt_axes.set_zlabel(axes[-3])
-        plt_axes.set_ylabel(axes[-2])
-        plt_axes.view_init(elev=15)
+        if isinstance(plt_axes, Axes3D):
+            plt_axes.set_zlabel(axes[-3])
+            plt_axes.set_ylabel(axes[-2])
+            plt_axes.view_init(elev=15)
+        else:
+            raise TypeError(
+                "Expected matplotlib to create an Axes3D object, "
+                f"instead got: {plt_axes}"
+            )
     elif ndims == 2:
         plt.figure(figsize=(6, 6))
         plt_axes = plt.axes()
@@ -208,7 +214,7 @@ def plot_spec(spec: Spec[Any], title: str | None = None):
             _plot_arrow(plt_axes, arrow_arr)
         elif splines:
             # Plot the starting arrow in the direction of the first point
-            arrow_arr = [(2 * a[0] - a[1], a[0]) for a in splines[0]]
+            arrow_arr = [np.array([2 * a[0] - a[1], a[0]]) for a in splines[0]]
             _plot_arrow(plt_axes, arrow_arr)
         else:
             # First point isn't moving, put a right caret marker

src/scanspec/sphinxext.py

@@ -1,5 +1,6 @@
 from contextlib import contextmanager
 
+from docutils.statemachine import StringList
 from matplotlib.sphinxext import plot_directive
 
 from . import __version__
@@ -25,7 +26,7 @@ class ExampleSpecDirective(plot_directive.PlotDirective):
     """Runs `plot_spec` on the ``spec`` definied in the content."""
 
     def run(self):
-        self.content = (
+        self.content = StringList(
             ["# Example Spec", "", "from scanspec.plot import plot_spec"]
             + [str(x) for x in self.content]
             + ["plot_spec(spec)"]

tests/test_specs.py

@@ -492,7 +492,7 @@ def test_gap_repeat() -> None:
 
 def test_gap_repeat_non_snake() -> None:
     # Check that no gap doesn't propogate to dim.gap for non-snaked axis
-    spec: Spec[Any] = Repeat(3, gap=False) * Line.bounded(x, 11, 19, 1)
+    spec: Spec[str] = Repeat(3, gap=False) * Line.bounded(x, 11, 19, 1)
     dim = spec.frames()
     assert len(dim) == 3
     assert dim.lower == {x: pytest.approx([11, 11, 11])}