Fix parsing of wildcard constraints

poetry/semver/__init__.py

@@ -60,7 +60,6 @@ def parse_single_constraint(constraint):  # type: (str) -> VersionConstraint
             high = version.stable.next_major
 
         return VersionRange(version, high, include_min=True)
-        return VersionRange()
 
     # PEP 440 Tilde range (~=)
     m = TILDE_PEP440_CONSTRAINT.match(constraint)

poetry/semver/patterns.py

@@ -13,7 +13,7 @@ COMPLETE_VERSION = re.compile("(?i)" + _COMPLETE_VERSION)
 CARET_CONSTRAINT = re.compile("(?i)^\^({})$".format(_COMPLETE_VERSION))
 TILDE_CONSTRAINT = re.compile("(?i)^~(?!=)({})$".format(_COMPLETE_VERSION))
 TILDE_PEP440_CONSTRAINT = re.compile("(?i)^~=({})$".format(_COMPLETE_VERSION))
-X_CONSTRAINT = re.compile("^(!= ?|==)?v?(\d+)(?:\.(\d+))?(?:\.(\d+))?(?:\.[xX*])+$")
+X_CONSTRAINT = re.compile("^(!=|==)?\s*v?(\d+)(?:\.(\d+))?(?:\.(\d+))?(?:\.[xX*])+$")
 BASIC_CONSTRAINT = re.compile(
     "(?i)^(<>|!=|>=?|<=?|==?)?\s*({})".format(_COMPLETE_VERSION)
 )

tests/semver/test_main.py

@@ -3,6 +3,7 @@ import pytest
 from poetry.semver import parse_constraint
 from poetry.semver import Version
 from poetry.semver import VersionRange
+from poetry.semver import VersionUnion
 
 
 @pytest.mark.parametrize(
@@ -113,6 +114,17 @@ def test_parse_constraint_multi(input):
 
 
 @pytest.mark.parametrize(
+    "input",
+    [">=2.7,!=3.0.*,!=3.1.*", ">=2.7, !=3.0.*, !=3.1.*", ">= 2.7, != 3.0.*, != 3.1.*"],
+)
+def test_parse_constraint_multi_wilcard(input):
+    assert parse_constraint(input) == VersionUnion(
+        VersionRange(Version(2, 7, 0), Version(3, 0, 0), True, False),
+        VersionRange(Version(3, 2, 0), None, True, False),
+    )
+
+
+@pytest.mark.parametrize(
     "input,constraint",
     [
         (