Update src/pip/_internal/req/req_install.py
@@ -445,7 +445,7 @@ class InstallRequirement(object):
try:
self.satisfied_by = pkg_resources.get_distribution(str(no_marker))
except pkg_resources.DistributionNotFound:
- pass
+ return
except pkg_resources.VersionConflict:
existing_dist = pkg_resources.get_distribution(
self.req.name
