Remove index.py and req/constructors.py's dependence on download.py.

src/pip/_internal/download.py

@@ -26,7 +26,6 @@ from pip._vendor.six import PY2
 #       why we ignore the type on this import
 from pip._vendor.six.moves import xmlrpc_client  # type: ignore
 from pip._vendor.six.moves.urllib import parse as urllib_parse
-from pip._vendor.six.moves.urllib import request as urllib_request
 
 import pip
 from pip._internal.exceptions import HashMismatch, InstallationError
@@ -37,7 +36,6 @@ from pip._internal.utils.encoding import auto_decode
 from pip._internal.utils.filesystem import check_path_owner, copy2_fixed
 from pip._internal.utils.glibc import libc_ver
 from pip._internal.utils.misc import (
-    ARCHIVE_EXTENSIONS,
     ask,
     ask_input,
     ask_password,
@@ -61,6 +59,7 @@ from pip._internal.utils.misc import (
 from pip._internal.utils.temp_dir import TempDirectory
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 from pip._internal.utils.ui import DownloadProgressProvider
+from pip._internal.utils.urls import get_url_scheme, url_to_path
 from pip._internal.vcs import vcs
 
 if MYPY_CHECK_RUNNING:
@@ -101,8 +100,8 @@ if MYPY_CHECK_RUNNING:
 
 
 __all__ = ['get_file_content',
-           'is_url', 'url_to_path', 'path_to_url',
-           'is_archive_file', 'unpack_vcs_link',
+           'path_to_url',
+           'unpack_vcs_link',
            'unpack_file_url', 'is_file_url',
            'unpack_http_url', 'unpack_url',
            'parse_content_disposition', 'sanitize_content_filename']
@@ -787,7 +786,7 @@ def get_file_content(url, comes_from=None, session=None):
             "get_file_content() missing 1 required keyword argument: 'session'"
         )
 
-    scheme = _get_url_scheme(url)
+    scheme = get_url_scheme(url)
 
     if scheme in ['http', 'https']:
         # FIXME: catch some errors
@@ -824,57 +823,6 @@ def get_file_content(url, comes_from=None, session=None):
 _url_slash_drive_re = re.compile(r'/*([a-z])\|', re.I)
 
 
-def _get_url_scheme(url):
-    # type: (Union[str, Text]) -> Optional[Text]
-    if ':' not in url:
-        return None
-    return url.split(':', 1)[0].lower()
-
-
-def is_url(name):
-    # type: (Union[str, Text]) -> bool
-    """Returns true if the name looks like a URL"""
-    scheme = _get_url_scheme(name)
-    if scheme is None:
-        return False
-    return scheme in ['http', 'https', 'file', 'ftp'] + vcs.all_schemes
-
-
-def url_to_path(url):
-    # type: (str) -> str
-    """
-    Convert a file: URL to a path.
-    """
-    assert url.startswith('file:'), (
-        "You can only turn file: urls into filenames (not %r)" % url)
-
-    _, netloc, path, _, _ = urllib_parse.urlsplit(url)
-
-    if not netloc or netloc == 'localhost':
-        # According to RFC 8089, same as empty authority.
-        netloc = ''
-    elif sys.platform == 'win32':
-        # If we have a UNC path, prepend UNC share notation.
-        netloc = '\\\\' + netloc
-    else:
-        raise ValueError(
-            'non-local file URIs are not supported on this platform: %r'
-            % url
-        )
-
-    path = urllib_request.url2pathname(netloc + path)
-    return path
-
-
-def is_archive_file(name):
-    # type: (str) -> bool
-    """Return True if `name` is a considered as an archive file."""
-    ext = splitext(name)[1].lower()
-    if ext in ARCHIVE_EXTENSIONS:
-        return True
-    return False
-
-
 def unpack_vcs_link(link, location):
     # type: (Link, str) -> None
     vcs_backend = _get_used_vcs_backend(link)

src/pip/_internal/index.py

@@ -21,7 +21,6 @@ from pip._vendor.requests.exceptions import HTTPError, RetryError, SSLError
 from pip._vendor.six.moves.urllib import parse as urllib_parse
 from pip._vendor.six.moves.urllib import request as urllib_request
 
-from pip._internal.download import is_url, url_to_path
 from pip._internal.exceptions import (
     BestVersionAlreadyInstalled,
     DistributionNotFound,
@@ -44,6 +43,8 @@ from pip._internal.utils.misc import (
 )
 from pip._internal.utils.packaging import check_requires_python
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.urls import url_to_path
+from pip._internal.vcs import is_url, vcs
 from pip._internal.wheel import Wheel
 
 if MYPY_CHECK_RUNNING:
@@ -79,7 +80,6 @@ def _match_vcs_scheme(url):
 
     Returns the matched VCS scheme, or None if there's no match.
     """
-    from pip._internal.vcs import vcs
     for scheme in vcs.schemes:
         if url.lower().startswith(scheme) and url[len(scheme)] in '+:':
             return scheme

src/pip/_internal/operations/prepare.py

@@ -13,12 +13,7 @@ from pip._internal.distributions import (
     make_distribution_for_install_requirement,
 )
 from pip._internal.distributions.installed import InstalledDistribution
-from pip._internal.download import (
-    is_dir_url,
-    is_file_url,
-    unpack_url,
-    url_to_path,
-)
+from pip._internal.download import is_dir_url, is_file_url, unpack_url
 from pip._internal.exceptions import (
     DirectoryUrlHashUnsupported,
     HashUnpinned,
@@ -32,6 +27,7 @@ from pip._internal.utils.logging import indent_log
 from pip._internal.utils.marker_files import write_delete_marker_file
 from pip._internal.utils.misc import display_path, normalize_path
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.urls import url_to_path
 
 if MYPY_CHECK_RUNNING:
     from typing import Optional

src/pip/_internal/req/constructors.py

@@ -20,15 +20,20 @@ from pip._vendor.packaging.requirements import InvalidRequirement, Requirement
 from pip._vendor.packaging.specifiers import Specifier
 from pip._vendor.pkg_resources import RequirementParseError, parse_requirements
 
-from pip._internal.download import is_archive_file, is_url, url_to_path
 from pip._internal.exceptions import InstallationError
 from pip._internal.models.index import PyPI, TestPyPI
 from pip._internal.models.link import Link
 from pip._internal.pyproject import make_pyproject_path
 from pip._internal.req.req_install import InstallRequirement
-from pip._internal.utils.misc import is_installable_dir, path_to_url
+from pip._internal.utils.misc import (
+    ARCHIVE_EXTENSIONS,
+    is_installable_dir,
+    path_to_url,
+    splitext,
+)
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
-from pip._internal.vcs import vcs
+from pip._internal.utils.urls import url_to_path
+from pip._internal.vcs import is_url, vcs
 from pip._internal.wheel import Wheel
 
 if MYPY_CHECK_RUNNING:
@@ -47,6 +52,15 @@ logger = logging.getLogger(__name__)
 operators = Specifier._operators.keys()
 
 
+def is_archive_file(name):
+    # type: (str) -> bool
+    """Return True if `name` is a considered as an archive file."""
+    ext = splitext(name)[1].lower()
+    if ext in ARCHIVE_EXTENSIONS:
+        return True
+    return False
+
+
 def _strip_extras(path):
     # type: (str) -> Tuple[str, Optional[str]]
     m = re.match(r'^(.+)(\[[^\]]+\])$', path)

src/pip/_internal/utils/urls.py

@@ -0,0 +1,42 @@
+import sys
+
+from pip._vendor.six.moves.urllib import parse as urllib_parse
+from pip._vendor.six.moves.urllib import request as urllib_request
+
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+
+if MYPY_CHECK_RUNNING:
+    from typing import Optional, Text, Union
+
+
+def get_url_scheme(url):
+    # type: (Union[str, Text]) -> Optional[Text]
+    if ':' not in url:
+        return None
+    return url.split(':', 1)[0].lower()
+
+
+def url_to_path(url):
+    # type: (str) -> str
+    """
+    Convert a file: URL to a path.
+    """
+    assert url.startswith('file:'), (
+        "You can only turn file: urls into filenames (not %r)" % url)
+
+    _, netloc, path, _, _ = urllib_parse.urlsplit(url)
+
+    if not netloc or netloc == 'localhost':
+        # According to RFC 8089, same as empty authority.
+        netloc = ''
+    elif sys.platform == 'win32':
+        # If we have a UNC path, prepend UNC share notation.
+        netloc = '\\\\' + netloc
+    else:
+        raise ValueError(
+            'non-local file URIs are not supported on this platform: %r'
+            % url
+        )
+
+    path = urllib_request.url2pathname(netloc + path)
+    return path

src/pip/_internal/vcs/__init__.py

@@ -3,7 +3,7 @@
 # (The test directory and imports protected by MYPY_CHECK_RUNNING may
 # still need to import from a vcs sub-package.)
 from pip._internal.vcs.versioncontrol import (  # noqa: F401
-    RemoteNotFoundError, make_vcs_requirement_url, vcs,
+    RemoteNotFoundError, is_url, make_vcs_requirement_url, vcs,
 )
 # Import all vcs modules to register each VCS in the VcsSupport object.
 import pip._internal.vcs.bazaar

src/pip/_internal/vcs/versioncontrol.py

@@ -22,6 +22,7 @@ from pip._internal.utils.misc import (
     rmtree,
 )
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.urls import get_url_scheme
 
 if MYPY_CHECK_RUNNING:
     from typing import (
@@ -39,6 +40,17 @@ __all__ = ['vcs']
 logger = logging.getLogger(__name__)
 
 
+def is_url(name):
+    # type: (Union[str, Text]) -> bool
+    """
+    Return true if the name looks like a URL.
+    """
+    scheme = get_url_scheme(name)
+    if scheme is None:
+        return False
+    return scheme in ['http', 'https', 'file', 'ftp'] + vcs.all_schemes
+
+
 def make_vcs_requirement_url(repo_url, rev, project_name, subdir=None):
     """
     Return the URL for a VCS requirement.

tests/unit/test_download.py

@@ -19,12 +19,10 @@ from pip._internal.download import (
     SafeFileCache,
     _copy_source_tree,
     _download_http_url,
-    _get_url_scheme,
     parse_content_disposition,
     sanitize_content_filename,
     unpack_file_url,
     unpack_http_url,
-    url_to_path,
 )
 from pip._internal.exceptions import HashMismatch
 from pip._internal.models.link import Link
@@ -301,48 +299,6 @@ def test_download_http_url__no_directory_traversal(tmpdir):
     assert actual == ['out_dir_file']
 
 
-@pytest.mark.parametrize("url,expected", [
-    ('http://localhost:8080/', 'http'),
-    ('file:c:/path/to/file', 'file'),
-    ('file:/dev/null', 'file'),
-    ('', None),
-])
-def test__get_url_scheme(url, expected):
-    assert _get_url_scheme(url) == expected
-
-
-@pytest.mark.parametrize("url,win_expected,non_win_expected", [
-    ('file:tmp', 'tmp', 'tmp'),
-    ('file:c:/path/to/file', r'C:\path\to\file', 'c:/path/to/file'),
-    ('file:/path/to/file', r'\path\to\file', '/path/to/file'),
-    ('file://localhost/tmp/file', r'\tmp\file', '/tmp/file'),
-    ('file://localhost/c:/tmp/file', r'C:\tmp\file', '/c:/tmp/file'),
-    ('file://somehost/tmp/file', r'\\somehost\tmp\file', None),
-    ('file:///tmp/file', r'\tmp\file', '/tmp/file'),
-    ('file:///c:/tmp/file', r'C:\tmp\file', '/c:/tmp/file'),
-])
-def test_url_to_path(url, win_expected, non_win_expected):
-    if sys.platform == 'win32':
-        expected_path = win_expected
-    else:
-        expected_path = non_win_expected
-
-    if expected_path is None:
-        with pytest.raises(ValueError):
-            url_to_path(url)
-    else:
-        assert url_to_path(url) == expected_path
-
-
-@pytest.mark.skipif("sys.platform != 'win32'")
-def test_url_to_path_path_to_url_symmetry_win():
-    path = r'C:\tmp\file'
-    assert url_to_path(path_to_url(path)) == path
-
-    unc_path = r'\\unc\share\path'
-    assert url_to_path(path_to_url(unc_path)) == unc_path
-
-
 @pytest.fixture
 def clean_project(tmpdir_factory, data):
     tmpdir = Path(str(tmpdir_factory.mktemp("clean_project")))

tests/unit/test_urls.py

@@ -0,0 +1,48 @@
+import sys
+
+import pytest
+
+from pip._internal.utils.misc import path_to_url
+from pip._internal.utils.urls import get_url_scheme, url_to_path
+
+
+@pytest.mark.parametrize("url,expected", [
+    ('http://localhost:8080/', 'http'),
+    ('file:c:/path/to/file', 'file'),
+    ('file:/dev/null', 'file'),
+    ('', None),
+])
+def test_get_url_scheme(url, expected):
+    assert get_url_scheme(url) == expected
+
+
+@pytest.mark.parametrize("url,win_expected,non_win_expected", [
+    ('file:tmp', 'tmp', 'tmp'),
+    ('file:c:/path/to/file', r'C:\path\to\file', 'c:/path/to/file'),
+    ('file:/path/to/file', r'\path\to\file', '/path/to/file'),
+    ('file://localhost/tmp/file', r'\tmp\file', '/tmp/file'),
+    ('file://localhost/c:/tmp/file', r'C:\tmp\file', '/c:/tmp/file'),
+    ('file://somehost/tmp/file', r'\\somehost\tmp\file', None),
+    ('file:///tmp/file', r'\tmp\file', '/tmp/file'),
+    ('file:///c:/tmp/file', r'C:\tmp\file', '/c:/tmp/file'),
+])
+def test_url_to_path(url, win_expected, non_win_expected):
+    if sys.platform == 'win32':
+        expected_path = win_expected
+    else:
+        expected_path = non_win_expected
+
+    if expected_path is None:
+        with pytest.raises(ValueError):
+            url_to_path(url)
+    else:
+        assert url_to_path(url) == expected_path
+
+
+@pytest.mark.skipif("sys.platform != 'win32'")
+def test_url_to_path_path_to_url_symmetry_win():
+    path = r'C:\tmp\file'
+    assert url_to_path(path_to_url(path)) == path
+
+    unc_path = r'\\unc\share\path'
+    assert url_to_path(path_to_url(unc_path)) == unc_path