# Buggy code
def get_requirement(self):
    base = "{0}".format(self.link)
    req = first(requirements.parse(base))
    if self.editable:
        req.editable = True
    if self.link and self.link.scheme.startswith("file"):
        if self.path:
            req.path = self.path
            req.local_file = True
            self._uri_scheme = "file"
            req.uri = None
    req.link = self.link
    return req


# Traceback (pip9.exceptions.InstallationError)
gtalarico@GUI-STUDIO:~/dev/repos/genome$ pipenv install --dev
Pipfile.lock not found, creating…
Locking [dev-packages] dependencies…
Locking [packages] dependencies…
341, in <listcomp>
c for c in req.parse_requirements(t, session=pip_requests)
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/req/req_file.py", line 93, in parse_requirements
for req in req_iter:
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/req/req_file.py", line 158, in process_line
isolated=isolated, options=req_options, wheel_cache=wheel_cache
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/req/req_install.py", line 235, in from_line
wheel_cache=wheel_cache, constraint=constraint)
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/req/req_install.py", line 91, in __init__
"Invalid requirement: '%s'\n%s" % (req, add_msg))
pip9.exceptions.InstallationError: Invalid requirement: '.\vendor\stargate==0.14.2'
Traceback (most recent call last):
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/_vendor/packaging/requirements.py", line 92, in __init__
req = REQUIREMENT.parseString(requirement_string)
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/_vendor/pyparsing.py", line 1617, in parseString
raise exc
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/_vendor/pyparsing.py", line 1607, in parseString
loc, tokens = self._parse( instring, 0 )
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/_vendor/pyparsing.py", line 1379, in _parseNoCache
loc,tokens = self.parseImpl( instring, preloc, doActions )
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/_vendor/pyparsing.py", line 3376, in parseImpl
loc, exprtokens = e._parse( instring, loc, doActions )
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/_vendor/pyparsing.py", line 1379, in _parseNoCache
loc,tokens = self.parseImpl( instring, preloc, doActions )
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/_vendor/pyparsing.py", line 3698, in parseImpl
return self.expr._parse( instring, loc, doActions, callPreParse=False )
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/_vendor/pyparsing.py", line 1379, in _parseNoCache
loc,tokens = self.parseImpl( instring, preloc, doActions )
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/_vendor/pyparsing.py", line 3359, in parseImpl
loc, resultlist = self.exprs[0]._parse( instring, loc, doActions, callPreParse=False )
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/_vendor/pyparsing.py", line 1383, in _parseNoCache
loc,tokens = self.parseImpl( instring, preloc, doActions )
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/_vendor/pyparsing.py", line 2670, in parseImpl
raise ParseException(instring, loc, self.errmsg, self)
pip9._vendor.pyparsing.ParseException: Expected W:(abcd...) (at char 0), (line:1, col:1)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/req/req_install.py", line 82, in __init__
req = Requirement(req)
File "/home/gtalarico/.pyenv/versions/3.6.5/lib/python3.6/site-packages/pipenv/vendor/pip9/_vendor/packaging/requirements.py", line 96, in __init__
requirement_string[e.loc:e.loc + 8]))
pip9._vendor.packaging.requirements.InvalidRequirement: Invalid requirement, parse error at "'.\\vendor'"
gtalarico@GUI-STUDIO:~/dev/repos/genome$

# Fixed code
def get_requirement(self):
    prefix = "-e " if self.editable else ""
    line = "{0}{1}".format(prefix, self.link.url)
    req = first(requirements.parse(line))
    if self.path and self.link and self.link.scheme.startswith("file"):
        req.local_file = True
        req.path = self.path
        req.uri = None
        self._uri_scheme = "file"
    if self.editable:
        req.editable = True
    req.link = self.link
    return req