Ignore poorly formed distribution version values. (#917)

poetry/semver/version.py

@@ -196,7 +196,11 @@ class Version(VersionRange):
 
     @classmethod
     def parse(cls, text):  # type: (str) -> Version
-        match = COMPLETE_VERSION.match(text)
+        try:
+            match = COMPLETE_VERSION.match(text)
+        except TypeError:
+            match = None
+
         if match is None:
             raise ParseVersionError('Unable to parse "{}".'.format(text))
 

tests/semver/test_version.py

@@ -3,6 +3,7 @@ import pytest
 from poetry.semver import EmptyConstraint
 from poetry.semver import Version
 from poetry.semver import VersionRange
+from poetry.semver.exceptions import ParseVersionError
 
 
 @pytest.mark.parametrize(
@@ -32,6 +33,12 @@ def test_parse_valid(input, version):
     assert parsed.text == input
 
 
+@pytest.mark.parametrize("input", [(None, "example")])
+def test_parse_invalid(input):
+    with pytest.raises(ParseVersionError):
+        Version.parse(input)
+
+
 def test_comparison():
     versions = [
         "1.0.0-alpha",