Add Subversion.get_vcs_version method (#6390)

Add Subversion.get_vcs_version method to return the version of the currently installed Subversion client.

AUTHORS.txt

@@ -214,6 +214,7 @@ Jeremy Stanley <[email protected]>
 Jeremy Zafran <[email protected]>
 Jim Garrison <[email protected]>
 Jivan Amara <[email protected]>
+John Hagen <[email protected]>
 John-Scott Atlakson <[email protected]>
 Jon Banafato <[email protected]>
 Jon Dufresne <[email protected]>

src/pip/_internal/vcs/subversion.py

@@ -8,6 +8,7 @@
 from pip._internal.utils.misc import (
     display_path, rmtree, split_auth_from_netloc,
 )
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
 from pip._internal.vcs import VersionControl, vcs
 
 _svn_xml_url_re = re.compile('url="([^"]+)"')
@@ -16,6 +17,9 @@
 _svn_info_xml_url_re = re.compile(r'<url>(.*)</url>')
 
 
+if MYPY_CHECK_RUNNING:
+    from typing import Optional, Tuple
+
 logger = logging.getLogger(__name__)
 
 
@@ -33,6 +37,36 @@ def should_add_vcs_url_prefix(cls, remote_url):
     def get_base_rev_args(rev):
         return ['-r', rev]
 
+    def get_vcs_version(self):
+        # type: () -> Optional[Tuple[int, ...]]
+        """Return the version of the currently installed Subversion client.
+
+        :return: A tuple containing the parts of the version information or
+            ``None`` if the version returned from ``svn`` could not be parsed.
+        :raises: BadCommand: If ``svn`` is not installed.
+        """
+        # Example versions:
+        #   svn, version 1.10.3 (r1842928)
+        #      compiled Feb 25 2019, 14:20:39 on x86_64-apple-darwin17.0.0
+        #   svn, version 1.7.14 (r1542130)
+        #      compiled Mar 28 2018, 08:49:13 on x86_64-pc-linux-gnu
+        version_prefix = 'svn, version '
+        version = self.run_command(['--version'], show_stdout=False)
+        if not version.startswith(version_prefix):
+            return None
+
+        version = version[len(version_prefix):].split()[0]
+        version_list = version.split('.')
+        try:
+            parsed_version = tuple(map(int, version_list))
+        except ValueError:
+            return None
+
+        if not parsed_version:
+            return None
+
+        return parsed_version
+
     def export(self, location):
         """Export the svn repository at the url to the destination location"""
         url, rev_options = self.get_url_rev_options(self.url)

tests/lib/__init__.py

@@ -897,6 +897,14 @@ def is_bzr_installed():
     return True
 
 
+def is_svn_installed():
+    try:
+        subprocess.check_output(('svn', '--version'))
+    except OSError:
+        return False
+    return True
+
+
 def need_bzr(fn):
     return pytest.mark.bzr(need_executable(
         'Bazaar', ('bzr', 'version', '--short')

tests/unit/test_vcs.py

@@ -1,22 +1,33 @@
+import os
+
 import pytest
 from mock import patch
 from pip._vendor.packaging.version import parse as parse_version
 
+from pip._internal.exceptions import BadCommand
 from pip._internal.vcs import (
     RevOptions, VersionControl, make_vcs_requirement_url,
 )
 from pip._internal.vcs.bazaar import Bazaar
 from pip._internal.vcs.git import Git, looks_like_hash
 from pip._internal.vcs.mercurial import Mercurial
 from pip._internal.vcs.subversion import Subversion
-from tests.lib import pyversion
+from tests.lib import is_svn_installed, pyversion
 
 if pyversion >= '3':
     VERBOSE_FALSE = False
 else:
     VERBOSE_FALSE = 0
 
 
+@pytest.mark.skipif(
+    'TRAVIS' not in os.environ,
+    reason='Subversion is only required under Travis')
+def test_ensure_svn_available():
+    """Make sure that svn is available when running in Travis."""
+    assert is_svn_installed()
+
+
 @pytest.mark.parametrize('args, expected', [
     # Test without subdir.
     (('git+https://example.com/pkg', 'dev', 'myproj'),
@@ -366,3 +377,49 @@ def test_subversion__get_url_rev_options():
 def test_get_git_version():
     git_version = Git().get_git_version()
     assert git_version >= parse_version('1.0.0')
+
+
+@pytest.mark.svn
+def test_subversion__get_vcs_version():
+    """
+    Test Subversion.get_vcs_version() against local ``svn``.
+    """
+    version = Subversion().get_vcs_version()
+    assert len(version) == 3
+    for part in version:
+        assert isinstance(part, int)
+    assert version[0] >= 1
+
+
+@pytest.mark.parametrize('svn_output, expected_version', [
+    ('svn, version 1.10.3 (r1842928)\n'
+     '   compiled Feb 25 2019, 14:20:39 on x86_64-apple-darwin17.0.0',
+     (1, 10, 3)),
+    ('svn, version 1.9.7 (r1800392)', (1, 9, 7)),
+    ('svn, version 1.9.7a1 (r1800392)', None),
+    ('svn, version 1.9 (r1800392)', (1, 9)),
+    ('svn, version .9.7 (r1800392)', None),
+    ('svn version 1.9.7 (r1800392)', None),
+    ('svn 1.9.7', None),
+    ('svn, version . .', None),
+    ('', None),
+])
+@patch('pip._internal.vcs.subversion.Subversion.run_command')
+def test_subversion__get_vcs_version_patched(mock_run_command, svn_output,
+                                             expected_version):
+    """
+    Test Subversion.get_vcs_version() against patched output.
+    """
+    mock_run_command.return_value = svn_output
+    version = Subversion().get_vcs_version()
+    assert version == expected_version
+
+
+@patch('pip._internal.vcs.subversion.Subversion.run_command')
+def test_subversion__get_vcs_version_svn_not_installed(mock_run_command):
+    """
+    Test Subversion.get_vcs_version() when svn is not installed.
+    """
+    mock_run_command.side_effect = BadCommand
+    with pytest.raises(BadCommand):
+        Subversion().get_vcs_version()