Address review comments

Signed-off-by: Tushar Goel <tushar.goel.dav@gmail.com>

Author: TG1999

src/univers/version_constraint.py

@@ -39,14 +39,6 @@ def operator_star(a, b):
     return True
 
 
-def operator_null(a, b):
-    """
-    Comparison operator for the star "^" constraint comparator. Since it does not matches
-    any version, it is always False.
-    """
-    return False
-
-
 # note: ORDER MATTER here: we tests startswith(key) for each key in sequence
 COMPARATORS = {
     ">=": operator.ge,
@@ -56,7 +48,6 @@ def operator_null(a, b):
     ">": operator.gt,
     "=": operator.eq,
     "*": operator_star,
-    "^": operator_null,
 }
 
 
@@ -159,10 +150,10 @@ def from_string(cls, string, version_class):
         if comparator not in COMPARATORS:
             raise ValueError(f"Unknown comparator: {comparator!r}")
 
-        if not version and comparator not in ["*", "^"]:
+        if not version and comparator != "*":
             raise ValueError("Empty version")
 
-        if comparator in ["*", "^"]:
+        if comparator == "*":
             version = None
         else:
             version = version_class(version)

src/univers/version_range.py

@@ -32,8 +32,6 @@ class InvalidVersionRange(Exception):
     "<": ">=",
     ">": "<=",
     "=": "!=",
-    "*": "^",
-    "^": "*",
 }
 
 
@@ -176,30 +174,30 @@ def from_versions(cls, sequence):
             constraints.append(constraint)
         return cls(constraints=constraints)
 
-    def inverse(self):
+    def invert(self):
         """
         Return the inverse of this VersionRange. For example, if this range is
         ">=1.0.0", the inverse is "<1.0.0".
         >>> VersionRange.from_string("vers:npm/>=1.0.0").inverse()
         NpmVersionRange(constraints=(VersionConstraint(comparator='<', version=SemverVersion(string='1.0.0')),))
         """
         inverted_constraints = []
+
+        if len(self.constraints) == 1 and self.constraints[0].comparator == "*":
+            # The inverse of "*" is an empty range.
+            return None
+
         for constraint in self.constraints:
             if constraint.comparator in INVERTED_COMPARATORS:
                 inverted_comparator = INVERTED_COMPARATORS[constraint.comparator]
             else:
                 raise NotImplementedError(
                     f"Cannot invert a range with a {constraint.comparator!r} comparator."
                 )
-            if inverted_comparator == "*" or inverted_comparator == "^":
-                inverted_constraint = VersionConstraint.from_string(
-                    string=inverted_comparator, version_class=self.version_class
-                )
-            else:
-                inverted_constraint = VersionConstraint(
-                    comparator=inverted_comparator,
-                    version=constraint.version,
-                )
+            inverted_constraint = VersionConstraint(
+                comparator=inverted_comparator,
+                version=constraint.version,
+            )
             inverted_constraints.append(inverted_constraint)
         return self.__class__(constraints=inverted_constraints)