Always read InstallRequirement.extras
@@ -55,7 +55,7 @@ class SpecifierRequirement(Requirement):
assert ireq.link is None, "This is a link, not a specifier"
self._ireq = ireq
self._factory = factory
- self.extras = ireq.req.extras
+ self.extras = set(ireq.extras)
def __str__(self):
# type: () -> str
