mypy: fix poetry.mixology

Relates-to: #5017

pyproject.toml

@@ -120,14 +120,6 @@ module = [
   'poetry.installation.executor',
   'poetry.installation.installer',
   'poetry.installation.pip_installer',
-  'poetry.mixology.assignment',
-  'poetry.mixology.failure',
-  'poetry.mixology.incompatibility',
-  'poetry.mixology.partial_solution',
-  'poetry.mixology.solutions.providers.python_requirement_solution_provider',
-  'poetry.mixology.solutions.solutions.python_requirement_solution',
-  'poetry.mixology.term',
-  'poetry.mixology.version_solver',
   'poetry.repositories.installed_repository',
   'poetry.utils.env',
 ]

src/poetry/mixology/assignment.py

@@ -41,7 +41,7 @@ class Assignment(Term):
         return self._index
 
     @property
-    def cause(self) -> Incompatibility:
+    def cause(self) -> Incompatibility | None:
         return self._cause
 
     @classmethod

src/poetry/mixology/failure.py

 from __future__ import annotations
 
 from typing import TYPE_CHECKING
+from typing import cast
 
 from poetry.core.semver.helpers import parse_constraint
 
@@ -114,8 +115,9 @@ class _Writer:
         conjunction = "So," if conclusion or incompatibility == self._root else "And"
         incompatibility_string = str(incompatibility)
 
-        cause = incompatibility.cause
-        details_for_cause = {}
+        cause: ConflictCause = cast(ConflictCause, incompatibility.cause)
+
+        details_for_cause: dict = {}
         if isinstance(cause.conflict.cause, ConflictCause) and isinstance(
             cause.other.cause, ConflictCause
         ):
@@ -136,7 +138,7 @@ class _Writer:
                     with_line = cause.conflict
                     without_line = cause.other
                     line = conflict_line
-                else:
+                elif other_line is not None:
                     with_line = cause.other
                     without_line = cause.conflict
                     line = other_line
@@ -200,7 +202,7 @@ class _Writer:
                     numbered=numbered,
                 )
             elif self._is_collapsible(derived):
-                derived_cause: ConflictCause = derived.cause
+                derived_cause: ConflictCause = cast(ConflictCause, derived.cause)
                 if isinstance(derived_cause.conflict.cause, ConflictCause):
                     collapsed_derived = derived_cause.conflict
                     collapsed_ext = derived_cause.other
@@ -239,7 +241,7 @@ class _Writer:
         if self._derivations[incompatibility] > 1:
             return False
 
-        cause: ConflictCause = incompatibility.cause
+        cause: ConflictCause = cast(ConflictCause, incompatibility.cause)
         if isinstance(cause.conflict.cause, ConflictCause) and isinstance(
             cause.other.cause, ConflictCause
         ):

src/poetry/mixology/incompatibility.py

@@ -50,7 +50,7 @@ class Incompatibility:
                 ref = term.dependency.complete_name
 
                 if ref in by_ref:
-                    by_ref[ref] = by_ref[ref].intersect(term)
+                    value = by_ref[ref].intersect(term)
 
                     # If we have two terms that refer to the same package but have a
                     # null intersection, they're mutually exclusive, making this
@@ -58,7 +58,8 @@ class Incompatibility:
                     # exclusive version ranges are incompatible. We should never derive
                     # an irrelevant incompatibility.
                     err_msg = f"Package '{ref}' is listed as a dependency of itself."
-                    assert by_ref[ref] is not None, err_msg
+                    assert value is not None, err_msg
+                    by_ref[ref] = value
                 else:
                     by_ref[ref] = term
 
@@ -83,23 +84,13 @@ class Incompatibility:
         return self._terms
 
     @property
-    def cause(
-        self,
-    ) -> (
-        RootCause
-        | NoVersionsCause
-        | DependencyCause
-        | ConflictCause
-        | PythonCause
-        | PlatformCause
-        | PackageNotFoundCause
-    ):
+    def cause(self) -> IncompatibilityCause:
         return self._cause
 
     @property
     def external_incompatibilities(
         self,
-    ) -> Iterator[ConflictCause | Incompatibility]:
+    ) -> Iterator[Incompatibility]:
         """
         Returns all external incompatibilities in this incompatibility's
         derivation graph.
@@ -134,18 +125,16 @@ class Incompatibility:
             assert len(self._terms) == 1
             assert self._terms[0].is_positive()
 
-            cause: PythonCause = self._cause
             text = f"{self._terse(self._terms[0], allow_every=True)} requires "
-            text += f"Python {cause.python_version}"
+            text += f"Python {self._cause.python_version}"
 
             return text
         elif isinstance(self._cause, PlatformCause):
             assert len(self._terms) == 1
             assert self._terms[0].is_positive()
 
-            cause: PlatformCause = self._cause
             text = f"{self._terse(self._terms[0], allow_every=True)} requires "
-            text += f"platform {cause.platform}"
+            text += f"platform {self._cause.platform}"
 
             return text
         elif isinstance(self._cause, NoVersionsCause):
@@ -307,7 +296,11 @@ class Incompatibility:
         return "".join(buffer)
 
     def _try_requires_through(
-        self, other: Incompatibility, details: dict, this_line: int, other_line: int
+        self,
+        other: Incompatibility,
+        details: dict,
+        this_line: int | None,
+        other_line: int | None,
     ) -> str | None:
         if len(self._terms) == 1 or len(other.terms) == 1:
             return None
@@ -385,7 +378,11 @@ class Incompatibility:
         return "".join(buffer)
 
     def _try_requires_forbidden(
-        self, other: Incompatibility, details: dict, this_line: int, other_line: int
+        self,
+        other: Incompatibility,
+        details: dict,
+        this_line: int | None,
+        other_line: int | None,
     ) -> str | None:
         if len(self._terms) != 1 and len(other.terms) != 1:
             return None

src/poetry/mixology/partial_solution.py

@@ -156,10 +156,10 @@ class PartialSolution:
         ref = assignment.dependency.complete_name
         negative_by_ref = self._negative.get(name)
         old_negative = None if negative_by_ref is None else negative_by_ref.get(ref)
-        if old_negative is None:
-            term = assignment
-        else:
-            term = assignment.intersect(old_negative)
+        term = (
+            assignment if old_negative is None else assignment.intersect(old_negative)
+        )
+        assert term is not None
 
         if term.is_positive():
             if name in self._negative:
@@ -208,7 +208,7 @@ class PartialSolution:
     def satisfies(self, term: Term) -> bool:
         return self.relation(term) == SetRelation.SUBSET
 
-    def relation(self, term: Term) -> int:
+    def relation(self, term: Term) -> str:
         positive = self._positive.get(term.dependency.complete_name)
         if positive is not None:
             return positive.relation(term)

src/poetry/mixology/solutions/providers/python_requirement_solution_provider.py

@@ -10,6 +10,8 @@ from crashtest.contracts.has_solutions_for_exception import HasSolutionsForExcep
 if TYPE_CHECKING:
     from crashtest.contracts.solution import Solution
 
+    from poetry.puzzle.exceptions import SolverProblemError
+
 
 class PythonRequirementSolutionProvider(HasSolutionsForException):
     def can_solve(self, exception: Exception) -> bool:
@@ -26,7 +28,7 @@ class PythonRequirementSolutionProvider(HasSolutionsForException):
 
         return bool(m)
 
-    def get_solutions(self, exception: Exception) -> list[Solution]:
+    def get_solutions(self, exception: SolverProblemError) -> list[Solution]:
         from poetry.mixology.solutions.solutions.python_requirement_solution import (
             PythonRequirementSolution,
         )

src/poetry/mixology/solutions/solutions/python_requirement_solution.py

@@ -6,18 +6,19 @@ from crashtest.contracts.solution import Solution
 
 
 if TYPE_CHECKING:
-    from poetry.mixology.incompatibility_cause import PackageNotFoundCause
+    from poetry.mixology.failure import SolveFailure
+    from poetry.puzzle.exceptions import SolverProblemError
 
 
 class PythonRequirementSolution(Solution):
-    def __init__(self, exception: PackageNotFoundCause) -> None:
+    def __init__(self, exception: SolverProblemError) -> None:
         from poetry.core.semver.helpers import parse_constraint
 
         from poetry.mixology.incompatibility_cause import PythonCause
 
         self._title = "Check your dependencies Python requirement."
 
-        failure = exception.error
+        failure: SolveFailure = exception.error
         version_solutions = []
         for incompatibility in failure._incompatibility.external_incompatibilities:
             if isinstance(incompatibility.cause, PythonCause):

src/poetry/mixology/term.py

@@ -49,7 +49,7 @@ class Term:
         )
 
     @functools.lru_cache(maxsize=None)
-    def relation(self, other: Term) -> int:
+    def relation(self, other: Term) -> str:
         """
         Returns the relationship between the package versions
         allowed by this term and another.
@@ -144,7 +144,7 @@ class Term:
         else:
             return None
 
-    def difference(self, other: Term) -> Term:
+    def difference(self, other: Term) -> Term | None:
         """
         Returns a Term that represents packages
         allowed by this term and not by the other

src/poetry/mixology/version_solver.py

@@ -159,7 +159,7 @@ class VersionSolver:
                     changed.add(str(self._propagate_incompatibility(root_cause)))
                     break
                 elif result is not None:
-                    changed.add(result)
+                    changed.add(str(result))
 
     def _propagate_incompatibility(
         self, incompatibility: Incompatibility
@@ -290,6 +290,9 @@ class VersionSolver:
             # than a derivation), then incompatibility is the root cause. We then
             # backjump to previous_satisfier_level, where incompatibility is
             # guaranteed to allow _propagate to produce more assignments.
+
+            # using assert to suppress mypy [union-attr]
+            assert most_recent_satisfier is not None
             if (
                 previous_satisfier_level < most_recent_satisfier.decision_level
                 or most_recent_satisfier.cause is None

src/poetry/puzzle/exceptions.py

 from __future__ import annotations
 
+from typing import TYPE_CHECKING
+
+
+if TYPE_CHECKING:
+    from poetry.mixology.failure import SolveFailure
+
 
 class SolverProblemError(Exception):
-    def __init__(self, error: Exception) -> None:
+    def __init__(self, error: SolveFailure) -> None:
         self._error = error
 
         super().__init__(str(error))
 
     @property
-    def error(self) -> Exception:
+    def error(self) -> SolveFailure:
         return self._error