fix(math): impartial games disjunctive sum invariants and lint

Author: morluto

src/jacobian/math/impartial_games/_models.py

@@ -221,3 +221,19 @@ class DisjunctiveSumResult(StrictModel):
     component_grundy_values: tuple[int, ...]
     is_p_position: bool
     component_count: int = Field(ge=1)
+
+    @model_validator(mode="after")
+    def require_exact_disjunctive_invariants(self) -> Self:
+        if self.component_count != len(self.component_grundy_values):
+            raise ValueError("component_count must match component_grundy_values length")
+        if any(value < 0 for value in self.component_grundy_values):
+            raise ValueError("component Grundy values must be nonnegative")
+        from functools import reduce
+        from operator import xor
+
+        expected = reduce(xor, self.component_grundy_values, 0)
+        if self.grundy_value != expected:
+            raise ValueError("grundy_value must be XOR of component_grundy_values")
+        if self.is_p_position != (expected == 0):
+            raise ValueError("is_p_position must agree with grundy_value == 0")
+        return self

src/jacobian/math/impartial_games/_operations.py

@@ -1,10 +1,10 @@
 """Wire adapters for exact bounded impartial-game operations."""
 
 from jacobian.math.impartial_games._models import (
-    DisjunctiveSumRequest,
-    DisjunctiveSumResult,
     BirthdayRequest,
     BirthdayResult,
+    DisjunctiveSumRequest,
+    DisjunctiveSumResult,
     GrundyEntry,
     GrundyTableRequest,
     GrundyTableResult,
@@ -67,8 +67,8 @@ def compute_subtraction_grundy_prefix(
 
 
 __all__ = [
-    "compute_disjunctive_sum",
     "compute_birthday",
+    "compute_disjunctive_sum",
     "compute_grundy_table",
     "compute_subtraction_grundy_prefix",
 ]

tests/math/impartial_games/test_disjunctive_sum.py

@@ -5,12 +5,10 @@
 
 from jacobian.math.impartial_games._models import (
     DisjunctiveSumRequest,
-    DisjunctiveSumResult,
 )
 from jacobian.math.impartial_games._operations import compute_disjunctive_sum
 from jacobian.math.impartial_games._tools import TOOLS
 
-
 # -- helpers -----------------------------------------------------------------
 
 _TERMINAL = {"positions": ["start"], "moves": []}