Prevent StopIteration from bubbling up in parse_requirements. Fixes #1285.

CHANGES.rst

+v38.5.2
+-------
+
+* #1285: Fixed RuntimeError in pkg_resources.parse_requirements
+  on Python 3.7 (stemming from PEP 479).
+
 v38.5.1
 -------
 

pkg_resources/__init__.py

@@ -3035,7 +3035,10 @@ def parse_requirements(strs):
         # If there is a line continuation, drop it, and append the next line.
         if line.endswith('\\'):
             line = line[:-2].strip()
-            line += next(lines)
+            try:
+                line += next(lines)
+            except StopIteration:
+                return
         yield Requirement(line)