Merge pull request #7965 from deveshks/warn-on-invalid-index-url

Warn if an invalid URL is passed with --index-url

Author: pradyunsg

news/7430.bugfix

@@ -0,0 +1 @@
+Warn if an invalid URL is passed with --index-url

src/pip/_internal/models/search_scope.py

@@ -77,11 +77,30 @@ def __init__(
     def get_formatted_locations(self):
         # type: () -> str
         lines = []
+        redacted_index_urls = []
         if self.index_urls and self.index_urls != [PyPI.simple_url]:
-            lines.append(
-                'Looking in indexes: {}'.format(', '.join(
-                    redact_auth_from_url(url) for url in self.index_urls))
-            )
+            for url in self.index_urls:
+
+                redacted_index_url = redact_auth_from_url(url)
+
+                # Parse the URL
+                purl = urllib_parse.urlsplit(redacted_index_url)
+
+                # URL is generally invalid if scheme and netloc is missing
+                # there are issues with Python and URL parsing, so this test
+                # is a bit crude. See bpo-20271, bpo-23505. Python doesn't
+                # always parse invalid URLs correctly - it should raise
+                # exceptions for malformed URLs
+                if not purl.scheme and not purl.netloc:
+                    logger.warning(
+                        'The index url "{}" seems invalid, '
+                        'please provide a scheme.'.format(redacted_index_url))
+
+                redacted_index_urls.append(redacted_index_url)
+
+            lines.append('Looking in indexes: {}'.format(
+                ', '.join(redacted_index_urls)))
+
         if self.find_links:
             lines.append(
                 'Looking in links: {}'.format(', '.join(

tests/functional/test_install.py

@@ -1769,6 +1769,31 @@ def test_ignore_yanked_file(script, data):
     assert 'Successfully installed simple-2.0\n' in result.stdout, str(result)
 
 
+def test_invalid_index_url_argument(script, shared_data):
+    """
+    Test the behaviour of an invalid --index-url argument
+    """
+
+    result = script.pip('install', '--index-url', '--user',
+                        shared_data.find_links3, "Dinner",
+                        expect_error=True)
+
+    assert 'WARNING: The index url "--user" seems invalid, ' \
+           'please provide a scheme.' in result.stderr, str(result)
+
+
+def test_valid_index_url_argument(script, shared_data):
+    """
+    Test the behaviour of an valid --index-url argument
+    """
+
+    result = script.pip('install', '--index-url',
+                        shared_data.find_links3,
+                        "Dinner")
+
+    assert 'Successfully installed Dinner' in result.stdout, str(result)
+
+
 def test_install_yanked_file_and_print_warning(script, data):
     """
     Test install a "yanked" file and print a warning.