Fix compatibility with Python <3.6

poetry/packages/dependency.py

@@ -282,6 +282,9 @@ class Dependency(object):
 
         return self._name == other.name and self._constraint == other.constraint
 
+    def __ne__(self, other):
+        return not self == other
+
     def __hash__(self):
         return hash((self._name, self._pretty_constraint))
 

poetry/pub/partial_solution.py

+from collections import OrderedDict
+
 from typing import Any
 from typing import Dict
 from typing import List
@@ -23,13 +25,13 @@ class PartialSolution:
         self._assignments = []  # type: List[Assignment]
 
         # The decisions made for each package.
-        self._decisions = {}  # type: Dict[str, Any]
+        self._decisions = OrderedDict()  # type: Dict[str, Any]
 
         # The intersection of all positive Assignments for each package, minus any
         # negative Assignments that refer to that package.
         #
         # This is derived from self._assignments.
-        self._positive = {}  # type: Dict[str, Term]
+        self._positive = OrderedDict()  # type: Dict[str, Term]
 
         # The union of all negative [Assignment]s for each package.
         #
@@ -37,7 +39,7 @@ class PartialSolution:
         # map.
         #
         # This is derived from self._assignments.
-        self._negative = {}  # type: Dict[str, Dict[str, Term]]
+        self._negative = OrderedDict()  # type: Dict[str, Dict[str, Term]]
 
         self._attempted_solutions = 1
         self._backtracking = False

poetry/pub/term.py

+# -*- coding: utf-8 -*-
 from poetry.packages import Dependency
 
 from .set_relation import SetRelation
 
 
-class Term:
+class Term(object):
     """
     A statement about a package which is true or false for a given selection of
     package versions.

poetry/pub/version_solver.py

+# -*- coding: utf-8 -*-
 import time
 
 from typing import Dict
@@ -11,7 +12,6 @@ from poetry.semver.semver import VersionRange
 from .failure import SolveFailure
 from .incompatibility import Incompatibility
 from .incompatibility_cause import ConflictCause
-from .incompatibility_cause import DependencyCause
 from .incompatibility_cause import NoVersionsCause
 from .incompatibility_cause import PackageNotFoundCause
 from .incompatibility_cause import RootCause

poetry/semver/semver/version.py

@@ -365,6 +365,9 @@ class Version(VersionRange):
             and self._build == other.build
         )
 
+    def __ne__(self, other):
+        return not self == other
+
     def __str__(self):
         return self._text