FIX: sympify unevaluated_expression instance attributes (#374)

* ENH: switch to tuples and improve signatures
* ENH: test sympification of `@unevaluated_expression()` attributes
* MAINT: remove redundant docstring in tests
* MAINT: sort test functions

src/ampform/sympy/_decorator.py

@@ -3,7 +3,7 @@
 import functools
 import inspect
 import sys
-from typing import TYPE_CHECKING, Callable, Iterable, TypeVar, overload
+from typing import TYPE_CHECKING, Any, Callable, Iterable, TypeVar, overload
 
 import sympy as sp
 
@@ -136,7 +136,7 @@ def new_method(cls, *args, evaluate: bool = False, **kwargs) -> type[ExprClass]:
         attr_values, kwargs = _get_attribute_values(attr_names, *args, **kwargs)
         attr_values = sp.sympify(attr_values)
         expr = sp.Expr.__new__(cls, *attr_values, **kwargs)
-        for name, value in zip(attr_names, args):
+        for name, value in zip(attr_names, attr_values):
             setattr(expr, name, value)
         if evaluate:
             return expr.evaluate()
@@ -146,7 +146,9 @@ def new_method(cls, *args, evaluate: bool = False, **kwargs) -> type[ExprClass]:
     return cls
 
 
-def _get_attribute_values(attr_names: list, *args, **kwargs) -> tuple[tuple, dict]:
+def _get_attribute_values(
+    attr_names: tuple[str, ...], *args, **kwargs
+) -> tuple[tuple, dict[str, Any]]:
     if len(args) == len(attr_names):
         return args, kwargs
     if len(args) > len(attr_names):
@@ -156,7 +158,7 @@ def _get_attribute_values(attr_names: list, *args, **kwargs) -> tuple[tuple, dic
         )
         raise ValueError(msg)
     attr_values = list(args)
-    remaining_attr_names = attr_names[len(args) :]
+    remaining_attr_names = list(attr_names[len(args) :])
     for name in list(remaining_attr_names):
         if name in kwargs:
             attr_values.append(kwargs.pop(name))
@@ -247,7 +249,7 @@ def wrapper(*args, **kwargs):
     return decorator
 
 
-def _get_attribute_names(cls: type) -> list[str]:
+def _get_attribute_names(cls: type) -> tuple[str, ...]:
     """Get the public attributes of a class with dataclass-like semantics.
 
     >>> class MyClass:
@@ -258,9 +260,11 @@ def _get_attribute_names(cls: type) -> list[str]:
     ...     def print(self): ...
     ...
     >>> _get_attribute_names(MyClass)
-    ['a', 'b']
+    ('a', 'b')
     """
-    return [v for v in cls.__annotations__ if not callable(v) if not v.startswith("_")]
+    return tuple(
+        k for k in cls.__annotations__ if not callable(k) if not k.startswith("_")
+    )
 
 
 @dataclass_transform()

tests/sympy/test_decorator.py

@@ -74,14 +74,22 @@ def my_func(*args, **kwargs) -> int:
     assert signature.return_annotation == "int"
 
 
+def test_set_assumptions():
+    @_set_assumptions(commutative=True, negative=False, real=True)
+    class MySqrt: ...
+
+    expr = MySqrt()
+    assert expr.is_commutative  # type: ignore[attr-defined]
+    assert not expr.is_negative  # type: ignore[attr-defined]
+    assert expr.is_real  # type: ignore[attr-defined]
+
+
 def test_unevaluated_expression():
     @unevaluated_expression
     class BreakupMomentum(sp.Expr):
-        r"""Breakup momentum of a two-body decay :math:`a \to 1+2`."""
-
-        s: sp.Basic
-        m1: sp.Basic
-        m2: sp.Basic
+        s: Any
+        m1: Any
+        m2: Any
         _latex_repr_ = R"q\left({s}\right)"
 
         def evaluate(self) -> sp.Expr:
@@ -90,11 +98,20 @@ def evaluate(self) -> sp.Expr:
 
     m0, ma, mb = sp.symbols("m0 m_a m_b")
     expr = BreakupMomentum(m0**2, ma, mb)
+    assert expr.s is m0**2
+    assert expr.m1 is ma
+    assert expr.m2 is mb
+    assert expr.is_commutative is True
     args_str = list(inspect.signature(expr.__new__).parameters)
     assert args_str == ["s", "m1", "m2", "args", "evaluate", "kwargs"]
     latex = sp.latex(expr)
     assert latex == R"q\left(m_{0}^{2}\right)"
 
+    q_value = BreakupMomentum(1, m1=0.2, m2=0.4)
+    assert isinstance(q_value.s, sp.Integer)
+    assert isinstance(q_value.m1, sp.Float)
+    assert isinstance(q_value.m2, sp.Float)
+
 
 def test_unevaluated_expression_callable():
     @unevaluated_expression(implement_doit=False)
@@ -115,13 +132,3 @@ class MySqrt(sp.Expr):
     expr = MySqrt(-1)
     assert expr.is_commutative
     assert expr.is_complex  # type: ignore[attr-defined]
-
-
-def test_set_assumptions():
-    @_set_assumptions(commutative=True, negative=False, real=True)
-    class MySqrt: ...
-
-    expr = MySqrt()
-    assert expr.is_commutative  # type: ignore[attr-defined]
-    assert not expr.is_negative  # type: ignore[attr-defined]
-    assert expr.is_real  # type: ignore[attr-defined]