Replace mypy with ty type checker

Switch from mypy to ty (v0.0.17, by Astral) for type checking. ty is
faster and from the same team as ruff/uv, simplifying the toolchain.

- Replace mypy with ty in dev dependencies and deduplicate pytest entry
- Remove [tool.mypy] config, add [tool.ty] config in pyproject.toml
- Update scripts (license_to_commit.sh, test_all_versions.sh) and docs
- Remove unused mypy-specific type: ignore comments from decorators.py
- Add ty-specific suppression comments for dynamic attribute patterns
- Add explicit import of importlib.machinery in main.py
- Fix pytest_pyosmo plugin using semantic names instead of function names
- Fix license_to_commit.sh to use uv run for all commands
- Add None checks in test_end_conditions.py for type safety

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: OPpuolitaival

CLAUDE.md

@@ -49,7 +49,7 @@ ruff format pyosmo/
 ruff format --check pyosmo/
 
 # Type checking
-mypy pyosmo/
+ty check pyosmo/
 ```
 
 ### Installation & Building
@@ -202,7 +202,7 @@ See `doc/strategic_vision_2025.md` for detailed roadmap and competitive analysis
 
 1. Make changes to `pyosmo/` code
 2. Run `ruff check pyosmo/ --fix` and `ruff format pyosmo/` to lint and format
-3. Run `mypy pyosmo/` for type checking
+3. Run `ty check pyosmo/` for type checking
 4. Run `pytest pyosmo/tests/` to verify tests pass
 5. Add/update tests in `pyosmo/tests/` for new functionality
 6. Verify coverage with `pytest pyosmo/tests/ --cov=pyosmo`

doc/development.md

@@ -54,7 +54,7 @@ ruff format --check pyosmo/
 ### Run type checking
 
 ```bash
-mypy pyosmo/
+ty check pyosmo/
 ```
 
 ### Run mutation testing

doc/documentation_improvements.md

@@ -286,7 +286,7 @@ ruff format .
 
 ### Type Checking
 ```bash
-mypy pyosmo/
+ty check pyosmo/
 ```
 
 ## Testing

doc/improvement_roadmap.md

@@ -85,8 +85,8 @@ This document provides a comprehensive roadmap for improving pyosmo based on:
 - [ ] Add type hints to algorithm classes
 - [ ] Add type hints to end_conditions classes
 - [ ] Add type hints to error_strategy classes
-- [ ] Run mypy for validation
-- [ ] Add mypy to CI/CD pipeline
+- [ ] Run ty for validation
+- [ ] Add ty to CI/CD pipeline
 
 #### 1.6 Docstring Coverage
 **Status**: Only 25.5% documented

license_to_commit.sh

@@ -4,7 +4,7 @@ set -e
 uv sync --all-extras
 uv run ruff check --fix
 uv run ruff format
-uv run mypy pyosmo/
-uv run mypy examples/
+uv run ty check pyosmo/
+uv run ty check examples/
 uv run pytest pyosmo/tests/
-pytest pytest_pyosmo/test_models_example.py
+uv run pytest pytest_pyosmo/test_models_example.py

pyosmo/decorators.py

@@ -10,7 +10,7 @@ def weight(value: int | float) -> Callable[[F], F]:
     """Make able to put weight in classes or functions by decorator @weight"""
 
     def decorator(func: F) -> F:
-        func.weight = value  # type: ignore[attr-defined]
+        func.weight = value
         return func
 
     return decorator
@@ -34,11 +34,11 @@ def __call__(self, func: Callable[..., Any]) -> Callable[..., Any]:
         def wrapper(*args: Any, **kwargs: Any) -> Any:
             return func(*args, **kwargs)
 
-        # Attach metadata
-        wrapper._osmo_step = True  # type: ignore[attr-defined]
-        wrapper._osmo_step_name = self.name or func.__name__  # type: ignore[attr-defined]
-        wrapper._osmo_weight = self.weight_value  # type: ignore[attr-defined]
-        wrapper._osmo_enabled = self.enabled  # type: ignore[attr-defined]
+        # Attach metadata (dynamic attributes for model discovery)
+        wrapper._osmo_step = True  # type: ignore[unresolved-attribute]
+        wrapper._osmo_step_name = self.name or func.__name__  # type: ignore[unresolved-attribute]
+        wrapper._osmo_weight = self.weight_value  # type: ignore[unresolved-attribute]
+        wrapper._osmo_enabled = self.enabled  # type: ignore[unresolved-attribute]
 
         return wrapper
 
@@ -102,17 +102,17 @@ def can_process(self) -> bool:
         guard_func = step_name_or_func
 
         def inline_decorator(func: Callable[..., Any]) -> Callable[..., Any]:
-            func._osmo_guard_inline = guard_func  # type: ignore[attr-defined]
-            func._osmo_guard_invert = invert  # type: ignore[attr-defined]
+            func._osmo_guard_inline = guard_func  # type: ignore[unresolved-attribute]
+            func._osmo_guard_invert = invert  # type: ignore[unresolved-attribute]
             return func
 
         return inline_decorator
 
     # Named guard
     def named_decorator(func: Callable[..., Any]) -> Callable[..., Any]:
-        func._osmo_guard = True  # type: ignore[attr-defined]
-        func._osmo_guard_for = step_name_or_func  # type: ignore[attr-defined]
-        func._osmo_guard_invert = invert  # type: ignore[attr-defined]
+        func._osmo_guard = True  # type: ignore[unresolved-attribute]
+        func._osmo_guard_for = step_name_or_func  # type: ignore[unresolved-attribute]
+        func._osmo_guard_invert = invert  # type: ignore[unresolved-attribute]
         return func
 
     return named_decorator
@@ -134,8 +134,8 @@ def before_login(self):
     """
 
     def decorator(func: F) -> F:
-        func._osmo_pre = True  # type: ignore[attr-defined]
-        func._osmo_pre_for = step_name  # type: ignore[attr-defined]
+        func._osmo_pre = True
+        func._osmo_pre_for = step_name
         return func
 
     return decorator
@@ -157,8 +157,8 @@ def after_login(self):
     """
 
     def decorator(func: F) -> F:
-        func._osmo_post = True  # type: ignore[attr-defined]
-        func._osmo_post_for = step_name  # type: ignore[attr-defined]
+        func._osmo_post = True
+        func._osmo_post_for = step_name
         return func
 
     return decorator
@@ -181,7 +181,7 @@ def checkout(self):
     """
 
     def decorator(func: F) -> F:
-        func._osmo_requires = list(requirements)  # type: ignore[attr-defined]
+        func._osmo_requires = list(requirements)
         return func
 
     return decorator
@@ -204,8 +204,8 @@ def complete_order(self):
     """
 
     def decorator(func: F) -> F:
-        func._osmo_requires = list(requirements)  # type: ignore[attr-defined]
-        func._osmo_requires_all = True  # type: ignore[attr-defined]
+        func._osmo_requires = list(requirements)
+        func._osmo_requires_all = True
         return func
 
     return decorator
@@ -228,8 +228,8 @@ def check_auth(self):
     """
 
     def decorator(func: F) -> F:
-        func._osmo_requires = list(requirements)  # type: ignore[attr-defined]
-        func._osmo_requires_any = True  # type: ignore[attr-defined]
+        func._osmo_requires = list(requirements)
+        func._osmo_requires_any = True
         return func
 
     return decorator
@@ -254,9 +254,9 @@ def get_cart_size(self) -> str:
     """
 
     def decorator(func: F) -> F:
-        func._osmo_variable = True  # type: ignore[attr-defined]
-        func._osmo_variable_name = name  # type: ignore[attr-defined]
-        func._osmo_variable_categories = categories  # type: ignore[attr-defined]
+        func._osmo_variable = True
+        func._osmo_variable_name = name
+        func._osmo_variable_categories = categories
         return func
 
     return decorator
@@ -276,5 +276,5 @@ def get_state(self) -> str:
     Returns:
         Decorated function
     """
-    func._osmo_state = True  # type: ignore[attr-defined]
+    func._osmo_state = True
     return func

pyosmo/main.py

@@ -1,4 +1,5 @@
 import importlib
+import importlib.machinery
 import inspect
 import sys
 from logging import getLogger

pyosmo/model.py

@@ -22,7 +22,7 @@ def default_weight(self) -> float:
 
     @property
     def func(self) -> Callable[[], Any]:
-        return getattr(self.object_instance, self.function_name)  # type: ignore[no-any-return]
+        return getattr(self.object_instance, self.function_name)
 
     def execute(self) -> Any:
         try:
@@ -63,7 +63,7 @@ def guard_name(self) -> str:
     def weight(self) -> float:
         # Check decorator-based weight first
         if hasattr(self.func, '_osmo_weight') and self.func._osmo_weight is not None:
-            return float(self.func._osmo_weight)
+            return float(self.func._osmo_weight)  # type: ignore[arg-type]
 
         # Check weight function (naming convention)
         weight_function = self.return_function_if_exists(f'weight_{self.name}')
@@ -72,7 +72,7 @@ def weight(self) -> float:
 
         # Check weight attribute (legacy decorator)
         if hasattr(self.func, 'weight'):
-            return float(self.func.weight)
+            return float(self.func.weight)  # type: ignore[arg-type]
 
         return self.default_weight  # Default value
 
@@ -85,7 +85,7 @@ def is_available(self) -> bool:
 
         # Check for inline guard (decorator-based)
         if hasattr(self.func, '_osmo_guard_inline'):
-            result = bool(self.func._osmo_guard_inline(self.object_instance))
+            result = bool(self.func._osmo_guard_inline(self.object_instance))  # type: ignore[operator]
             # Apply invert if specified
             if hasattr(self.func, '_osmo_guard_invert') and self.func._osmo_guard_invert:
                 result = not result

pyosmo/tests/test_end_conditions.py

@@ -117,6 +117,8 @@ def test_step_coverage_mid_range():
     # With 2 steps and 50% coverage, at least 1 step must have been used
     step_first = osmo.model.get_step_by_name('step_first')
     step_second = osmo.model.get_step_by_name('step_second')
+    assert step_first is not None
+    assert step_second is not None
     used_first = osmo.history.get_step_count(step_first) > 0
     used_second = osmo.history.get_step_count(step_second) > 0
     assert used_first or used_second
@@ -154,5 +156,7 @@ def guard_second(self):
     # Suite should stop once both steps have been used across multiple tests
     step_first = osmo.model.get_step_by_name('step_first')
     step_second = osmo.model.get_step_by_name('step_second')
+    assert step_first is not None
+    assert step_second is not None
     assert osmo.history.get_step_count(step_first) > 0
     assert osmo.history.get_step_count(step_second) > 0

pyproject.toml

@@ -30,12 +30,10 @@ dependencies = [
 
 [project.optional-dependencies]
 dev = [
-    "pytest>=7.0",
-    "mypy>=1.18.2",
     "pytest>=9.0.0",
     "hypothesis>=6.0",
     "ruff>=0.1.0",
-    "mypy>=1.0",
+    "ty>=0.0.17",
 ]
 
 [project.scripts]
@@ -91,19 +89,8 @@ runner = "python -m pytest pyosmo/tests/"
 tests_dir = "pyosmo/tests/"
 dict_synonyms = "Struct, NamedStruct"
 
-[tool.mypy]
-python_version = "3.11"
-warn_return_any = true
-warn_unused_configs = true
-disallow_untyped_defs = false
-disallow_any_generics = false
-check_untyped_defs = true
-no_implicit_optional = true
-warn_redundant_casts = true
-warn_unused_ignores = true
-warn_no_return = true
-strict_equality = true
+[tool.ty.environment]
+python-version = "3.11"
 
-[[tool.mypy.overrides]]
-module = "pyosmo.tests.*"
-disallow_untyped_defs = false
+[tool.ty.src]
+include = ["pyosmo/"]