Better handling of file URLs

This allows for using `file:///absolute/path`, which was previously
prevented due to the missing `netloc`.

This allows for all file URLs that `urlunparse` turns back into the
original URL to be valid.

Author: blueyed

CHANGELOG.rst

@@ -7,6 +7,14 @@ Changelog
 
 * Fix string representation of PEP 508 direct URL requirements with markers.
 
+* Better handling of file URLs
+
+  This allows for using ``file:///absolute/path``, which was previously
+  prevented due to the missing ``netloc``.
+
+  This allows for all file URLs that ``urlunparse`` turns back into the
+  original URL to be valid.
+
 
 18.0 - 2018-09-26
 ~~~~~~~~~~~~~~~~~

packaging/requirements.py

@@ -99,7 +99,10 @@ def __init__(self, requirement_string):
         self.name = req.name
         if req.url:
             parsed_url = urlparse.urlparse(req.url)
-            if not (parsed_url.scheme and parsed_url.netloc) or (
+            if parsed_url.scheme == 'file':
+                if urlparse.urlunparse(parsed_url) != req.url:
+                    raise InvalidRequirement("Invalid URL given")
+            elif not (parsed_url.scheme and parsed_url.netloc) or (
                     not parsed_url.scheme and not parsed_url.netloc):
                 raise InvalidRequirement("Invalid URL: {0}".format(req.url))
             self.url = req.url

tests/test_requirements.py

@@ -107,6 +107,18 @@ def test_invalid_url(self):
         assert "Invalid URL: " in str(e)
         assert "gopher:/foo/com" in str(e)
 
+    def test_file_url(self):
+        req = Requirement("name @ file:///absolute/path")
+        self._assert_requirement(req, "name", "file:///absolute/path")
+        req = Requirement("name @ file://.")
+        self._assert_requirement(req, "name", "file://.")
+
+    def test_invalid_file_urls(self):
+        with pytest.raises(InvalidRequirement):
+            Requirement("name @ file:.")
+        with pytest.raises(InvalidRequirement):
+            Requirement("name @ file:/.")
+
     def test_extras_and_url_and_marker(self):
         req = Requirement(
             "name [fred,bar] @ http://foo.com ; python_version=='2.7'")