One ruff rule set, defined in pyproject and used by CI

.github/workflows/ci.yml

@@ -31,7 +31,7 @@ jobs:
           version: "0.10.9"
       - run: uv python install 3.14
       - run: uv sync --python 3.14 --all-extras --locked
-      - run: uv run ruff check --isolated --select E4,E7,E9,F src tests
+      - run: uv run ruff check src tests
 
   qualify:
     name: Qualify (${{ matrix.os }}, Python ${{ matrix.python-version }})

pyproject.toml

@@ -48,5 +48,15 @@ exclude = ["/.workspace", "/publish.sh"]
 [tool.ruff]
 line-length = 100
 
+[tool.ruff.lint]
+# One definition, used by CI and by a bare `ruff check` alike. E4/E7/E9/F is what
+# ruff enforces with no configuration at all; I, UP and B are the three that pay
+# for themselves here - import order, syntax this package's floor (3.10) already
+# supports, and the bugbear checks that catch a real defect rather than a style
+# preference. The wider default set is not adopted: S102 and BLE001 both fire on
+# deliberate choices - `exec` rebuilds a student's saved component, and a broad
+# `except` is what stops one wrong component from ending their session.
+select = ["E4", "E7", "E9", "F", "I", "UP", "B"]
+
 [tool.pytest.ini_options]
 testpaths = ["tests"]

src/ml4t_coursework/checks.py

@@ -8,8 +8,9 @@
 
 from __future__ import annotations
 
+from collections.abc import Callable
 from dataclasses import dataclass, field
-from typing import Any, Callable
+from typing import Any
 
 import numpy as np
 import pandas as pd
@@ -93,7 +94,8 @@ def same(left: Any, right: Any, tol: float = 1e-12) -> bool:
         return bool(np.allclose(left.to_numpy(dtype=float), right.to_numpy(dtype=float),
                                 atol=tol, rtol=0, equal_nan=True))
     if isinstance(left, (list, tuple)) and isinstance(right, (list, tuple)):
-        return len(left) == len(right) and all(same(a, b, tol) for a, b in zip(left, right))
+        return len(left) == len(right) and all(
+            same(a, b, tol) for a, b in zip(left, right, strict=True))
     if isinstance(left, pd.Index) and isinstance(right, pd.Index):
         return left.equals(right)
     if isinstance(left, np.ndarray) and isinstance(right, np.ndarray):
@@ -187,7 +189,7 @@ def evaluate(contract, obj) -> Conformance:
         lambda: run_invariants(contract, obj),
     ]
     names = ["interface", "leakage probe", "determinism", "domain invariants"]
-    for name, stage in zip(names, stages):
+    for name, stage in zip(names, stages, strict=True):
         try:
             result.checks.extend(stage())
         except Failure as failure:

src/ml4t_coursework/components.py

@@ -12,7 +12,8 @@
 import inspect
 import json
 import textwrap
-from typing import Any, Callable, Sequence
+from collections.abc import Callable, Sequence
+from typing import Any
 
 from . import contracts, project
 from .checks import Conformance, evaluate
@@ -187,7 +188,7 @@ def load_component(name: str, quiet: bool = False) -> Any:
 def status() -> str:
     """Every component the course asks for, and where each one stands."""
     lines = []
-    for name, contract in sorted(contracts.load_all().items()):
+    for name, _contract in sorted(contracts.load_all().items()):
         meta = _meta(name)
         if meta is None:
             state = "not written yet"

src/ml4t_coursework/contracts.py

@@ -16,11 +16,12 @@
 
 import importlib
 import pkgutil
+from collections.abc import Callable
 from dataclasses import dataclass
 from types import ModuleType
-from typing import Any, Callable
+from typing import Any
 
-CONTRACTS: dict[str, "Contract"] = {}
+CONTRACTS: dict[str, Contract] = {}
 
 _SOURCES: list[str] = [f"{__package__}.reference"]
 _LOADED: set[str] = set()

src/ml4t_coursework/course.py

@@ -15,7 +15,7 @@
 
 from dataclasses import dataclass
 
-COURSES: dict[str, "Course"] = {}
+COURSES: dict[str, Course] = {}
 _active: str | None = None
 
 

src/ml4t_coursework/markets.py

@@ -16,11 +16,11 @@
 
 from __future__ import annotations
 
+from collections.abc import Callable
 from dataclasses import dataclass, field
 from pathlib import Path
-from typing import Callable
 
-MARKETS: dict[str, "MarketSpec"] = {}
+MARKETS: dict[str, MarketSpec] = {}
 
 BARS_PER_YEAR = {"daily": 252, "8h": 3 * 365, "hourly": 24 * 365, "weekly": 52}
 

src/ml4t_coursework/reference/_config.py

@@ -7,7 +7,8 @@
 
 from __future__ import annotations
 
-from typing import Any, Callable
+from collections.abc import Callable
+from typing import Any
 
 from ..checks import require
 

src/ml4t_coursework/reference/fold_splitter.py

@@ -43,7 +43,7 @@ def _interface(obj) -> None:
     for k, fold in enumerate(folds):
         require(isinstance(fold, tuple) and len(fold) == 2, "interface",
                 "each fold to be a (train, validation) pair", f"fold {k} is {type(fold).__name__}")
-        for part, label in zip(fold, ("train", "validation")):
+        for part, label in zip(fold, ("train", "validation"), strict=True):
             require(len(part) > 0, "interface", f"a non-empty {label} block",
                     f"fold {k}'s {label} block is empty")
 

src/ml4t_coursework/reference/model_gbm.py

@@ -27,7 +27,7 @@ def __init__(self, seed: int = seed, max_depth: int = max_depth,
             self.model_ = None
             self.columns_ = None
 
-        def fit(self, X: pd.DataFrame, y: pd.Series) -> "GbmModel":
+        def fit(self, X: pd.DataFrame, y: pd.Series) -> GbmModel:
             from sklearn.ensemble import HistGradientBoostingRegressor
 
             self.columns_ = list(X.columns)

src/ml4t_coursework/reference/model_linear.py

@@ -23,7 +23,7 @@ def __init__(self, alpha: float = alpha):
             self.intercept_ = None
             self.columns_ = None
 
-        def fit(self, X: pd.DataFrame, y: pd.Series) -> "LinearModel":
+        def fit(self, X: pd.DataFrame, y: pd.Series) -> LinearModel:
             self.columns_ = list(X.columns)
             design = X.to_numpy(dtype=float)
             centre = design.mean(axis=0)

src/ml4t_coursework/reference/preprocessor.py

@@ -26,7 +26,7 @@ def __init__(self, clip: float = clip):
             self.spread_ = None
             self.fill_ = None
 
-        def fit(self, X: pd.DataFrame) -> "Preprocessor":
+        def fit(self, X: pd.DataFrame) -> Preprocessor:
             self.lower_ = X.quantile(self.clip)
             self.upper_ = X.quantile(1 - self.clip)
             trimmed = X.clip(self.lower_, self.upper_, axis=1)

src/ml4t_coursework/runner.py

@@ -19,8 +19,9 @@
 from __future__ import annotations
 
 import datetime as dt
+from collections.abc import Callable
 from dataclasses import dataclass
-from typing import Any, Callable
+from typing import Any
 
 import numpy as np
 import pandas as pd

tests/test_helper.py

@@ -7,8 +7,17 @@
 import pandas as pd
 import pytest
 
-from ml4t_coursework import (append_result, contract, load_component, project, report, results,
-                              save_component, source_of, status)
+from ml4t_coursework import (
+    append_result,
+    contract,
+    load_component,
+    project,
+    report,
+    results,
+    save_component,
+    source_of,
+    status,
+)
 from ml4t_coursework.components import _meta
 
 

tests/test_runner.py

@@ -13,9 +13,11 @@
 import pytest
 
 from ml4t_coursework import fixtures, markets, project, runner
+
 # `ml4t_coursework.results` is shadowed by the function of the same name that the
 # package re-exports, so the module's own names are imported directly.
-from ml4t_coursework.results import REQUIRED, results as results_log
+from ml4t_coursework.results import REQUIRED
+from ml4t_coursework.results import results as results_log
 
 
 @pytest.fixture