Review pass and upstream merge

Author: npapapietro

src/poetry/core/constraints/generic/constraint.py

@@ -78,7 +78,11 @@ def allows(self, other: BaseConstraint) -> bool:
 
         """
 
-        if not isinstance(other, Constraint) or other.operator != "==":
+        if not isinstance(other, Constraint) or other.operator not in {
+            "==",
+            "in",
+            "not in",
+        }:
             raise ValueError(
                 f"Invalid argument for allows"
                 f' ("other" must be a constraint with operator "=="): {other}'
@@ -95,18 +99,13 @@ def allows(self, other: BaseConstraint) -> bool:
 
         if is_equal_op:
             return self._value == other.value
-        if is_non_equal_op:
-            return self._value != other.value
 
-        if (
-            is_in_op
-            and is_other_in_op
-            or is_other_in_op
-            or is_in_op
-            and is_other_equal_op
-        ):
+        if is_in_op and is_other_in_op or is_in_op and is_other_equal_op:
             return bool(self._trans_op_str["in"](other.value, self._value))
 
+        if is_non_equal_op and not (is_other_in_op or is_other_not_in_op):
+            return self._value != other.value
+
         if (
             is_in_op
             and is_other_non_equal_op

src/poetry/core/version/markers.py

@@ -315,9 +315,6 @@ def __hash__(self) -> int:
 
 
 class SingleMarker(SingleMarkerLike[Union[BaseConstraint, VersionConstraint]]):
-    _CONSTRAINT_RE = re.compile(
-        r"""(?i)^((~=|!=|>=?|<=?|==?=?|not in|in)?\s*.+)|(".+"|'.+'\s*(not in|in))$"""
-    )
     _CONSTRAINT_RE_PATTERN_1 = re.compile(
         r"(?i)^(?P<op>~=|!=|>=?|<=?|==?=?|not in|in)?\s*(?P<value>.+)$"
     )
@@ -346,11 +343,6 @@ def __init__(
         original_constraint_string = constraint_string = str(constraint)
         self._swapped_name_value: bool = swapped_name_value
 
-        # Extract operator and value
-        m = self._CONSTRAINT_RE.match(constraint_string)
-        if m is None:
-            raise InvalidMarker(f"Invalid marker for '{name}': {constraint_string}")
-
         if swapped_name_value:
             pattern = self._CONSTRAINT_RE_PATTERN_2
         else: