Fix pip download VCS scp-like URLs

news/6296.bugfix

@@ -0,0 +1 @@
+Fix ``pip download`` scp-like VCS URLs. For example, ``pip download [email protected]:pypa/pip``.

setup.cfg

@@ -1,6 +1,7 @@
 [isort]
 skip =
     .tox,
+    .venv,
     .scratch,
     _vendor,
     data
@@ -16,6 +17,7 @@ include_trailing_comma = true
 [flake8]
 exclude =
     .tox,
+    .venv,
     .scratch,
     _vendor,
     data

src/pip/_internal/download.py

@@ -53,7 +53,7 @@
     )
     from pip._internal.models.link import Link
     from pip._internal.utils.hashes import Hashes
-    from pip._internal.vcs import AuthInfo
+    from pip._internal.vcs import AuthInfo, VersionControl
 
 try:
     import ssl  # noqa
@@ -456,11 +456,15 @@ def get_file_content(url, comes_from=None, session=None):
 
 def is_url(name):
     # type: (Union[str, Text]) -> bool
-    """Returns true if the name looks like a URL"""
+    """Returns true if the name looks like a URL or a valid VCS URL"""
+    if is_vcs_url(name):
+        return True
+
     if ':' not in name:
         return False
+
     scheme = name.split(':', 1)[0].lower()
-    return scheme in ['http', 'https', 'file', 'ftp'] + vcs.all_schemes
+    return scheme in ['http', 'https', 'file', 'ftp']
 
 
 def url_to_path(url):
@@ -502,20 +506,24 @@ def is_archive_file(name):
 
 
 def unpack_vcs_link(link, location):
-    vcs_backend = _get_used_vcs_backend(link)
+    # type: (Link, str) -> None
+    backend_cls = vcs.get_backend_by_url(link.url)
+    vcs_backend = backend_cls(link.url)
     vcs_backend.unpack(location)
 
 
-def _get_used_vcs_backend(link):
+def _get_used_vcs_backend(url):
+    # type: (Text) -> Optional[VersionControl]
     for backend in vcs.backends:
-        if link.scheme in backend.schemes:
-            vcs_backend = backend(link.url)
+        if backend.is_valid_url(url):
+            vcs_backend = backend(url)
             return vcs_backend
+    return None
 
 
-def is_vcs_url(link):
-    # type: (Link) -> bool
-    return bool(_get_used_vcs_backend(link))
+def is_vcs_url(url):
+    # type: (Text) -> bool
+    return bool(vcs.get_backend_by_url(url))
 
 
 def is_file_url(link):
@@ -857,7 +865,7 @@ def unpack_url(
         would ordinarily raise HashUnsupported) are allowed.
     """
     # non-editable vcs urls
-    if is_vcs_url(link):
+    if is_vcs_url(link.url):
         unpack_vcs_link(link, location)
 
     # file urls

src/pip/_internal/models/link.py

@@ -156,8 +156,4 @@ def is_artifact(self):
         it points to an "abstract" thing like a path or a VCS location.
         """
         from pip._internal.vcs import vcs
-
-        if self.scheme in vcs.all_schemes:
-            return False
-
-        return True
+        return not bool(vcs.get_backend_by_url(self.url))

src/pip/_internal/operations/prepare.py

@@ -19,7 +19,6 @@
 from pip._internal.utils.logging import indent_log
 from pip._internal.utils.misc import display_path, normalize_path
 from pip._internal.utils.typing import MYPY_CHECK_RUNNING
-from pip._internal.vcs import vcs
 
 if MYPY_CHECK_RUNNING:
     from typing import Any, Optional
@@ -288,7 +287,7 @@ def prepare_linked_requirement(
                 # we would report less-useful error messages for
                 # unhashable requirements, complaining that there's no
                 # hash provided.
-                if is_vcs_url(link):
+                if is_vcs_url(link.url):
                     raise VcsHashUnsupported()
                 elif is_file_url(link) and is_dir_url(link):
                     raise DirectoryUrlHashUnsupported()
@@ -349,7 +348,7 @@ def prepare_linked_requirement(
                 abstract_dist.prep_for_dist(finder, self.build_isolation)
             if self._download_should_save:
                 # Make a .zip of the source_dir we already created.
-                if req.link.scheme in vcs.all_schemes:
+                if not req.link.is_artifact:
                     req.archive(self.download_dir)
         return abstract_dist
 

src/pip/_internal/vcs/__init__.py

@@ -172,6 +172,18 @@ def get_backend(self, name):
             return self._registry[name]
         return None
 
+    def get_backend_by_url(self, url):
+        # type: (Text) -> Optional[Type[VersionControl]]
+        """
+        Return the backend class of the version control if found by given
+        URL, e.g. vcs.get_backend_by_url('git+https://github.com/pypa/pip.git')
+        """
+
+        for backend in self.backends:
+            if backend.is_valid_url(url):
+                return backend
+        return None
+
 
 vcs = VcsSupport()
 
@@ -532,3 +544,14 @@ def controls_location(cls, location):
         the Git override checks that Git is actually available.
         """
         return cls.is_repository_directory(location)
+
+    @classmethod
+    def is_valid_url(cls, url):
+        # type: (Text) -> bool
+        """
+        Return whether an URL has a supported scheme for this Version Control.
+        """
+        scheme = urllib_parse.urlsplit(url)[0]
+        if scheme in cls.schemes:
+            return True
+        return False

src/pip/_internal/vcs/git.py

@@ -14,8 +14,12 @@
     display_path, make_vcs_requirement_url, redact_password_from_url,
 )
 from pip._internal.utils.temp_dir import TempDirectory
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 from pip._internal.vcs import RemoteNotFoundError, VersionControl, vcs
 
+if MYPY_CHECK_RUNNING:
+    from typing import Text
+
 urlsplit = urllib_parse.urlsplit
 urlunsplit = urllib_parse.urlunsplit
 
@@ -365,5 +369,20 @@ def controls_location(cls, location):
                          "because git is not available", location)
             return False
 
+    @classmethod
+    def is_valid_url(cls, url):
+        # type: (Text) -> bool
+        """
+        Return whether an URL has a supported scheme for this Version Control.
+
+        This overrided method handles scp-like URLs,
+        e.g. 'user@hostname:user/repo.git'.
+        """
+
+        scheme, _, path, _, _ = urlsplit(url)
+        if not scheme and path.startswith('git+'):
+            return True
+        return super(Git, cls).is_valid_url(url)
+
 
 vcs.register(Git)

tests/functional/test_download.py

@@ -166,6 +166,22 @@ def test_download_vcs_link(script):
     assert script.site_packages / 'piptestpackage' not in result.files_created
 
 
+@pytest.mark.network
+def test_download_vcs_scp_like_url(script):
+    """
+    It should download a vcs scp-like URL, for example:
+    git+user@hostname:user/repo.git. Test for the issue #6293.
+    """
+    result = script.pip(
+        'download', '-d', '.', '[email protected]:pypa/pip-test-package.git'
+    )
+    assert (
+        Path('scratch') / 'pip-test-package-0.1.1.zip'
+        in result.files_created
+    )
+    assert script.site_packages / 'piptestpackage' not in result.files_created
+
+
 def test_only_binary_set_then_download_specific_platform(script, data):
     """
     Confirm that specifying an interpreter/platform constraint