got setup.py extras working (apparently)

Signed-off-by: Kenneth Reitz <me@kennethreitz.org>

pipenv/patched/piptools/repositories/pypi.py

@@ -183,6 +183,14 @@ class PyPIRepository(BaseRepository):
         if not (ireq.editable or is_pinned_requirement(ireq)):
             raise TypeError('Expected pinned or editable InstallRequirement, got {}'.format(ireq))
 
+        setup_requires = {}
+        if ireq.editable:
+            dist = ireq.get_dist()
+            if dist.has_metadata('requires.txt'):
+                setup_requires = self.finder.get_extras_links(
+                    dist.get_metadata_lines('requires.txt')
+                )
+
         if ireq not in self._dependencies_cache:
             if ireq.link and not ireq.link.is_artifact:
                 # No download_dir for VCS sources.  This also works around pip
@@ -204,6 +212,15 @@ class PyPIRepository(BaseRepository):
                                     ignore_compatibility=True
                                     )
             result = reqset._prepare_file(self.finder, ireq, ignore_requires_python=True)
+            if setup_requires:
+                for section in setup_requires:
+                    python_version = section
+                    for value in setup_requires[section]:
+                        if ':' in value:
+                            python_version = value[1:-1]
+                        else:
+                            result = result + [InstallRequirement.from_line("{0}{1}".format(value, python_version).replace(':', ';'))]
+
             if reqset.requires_python:
 
                 marker = 'python_version=="{0}"'.format(reqset.requires_python.replace(' ', ''))