confirming dependencies when uninstall package

news/4245.feature

@@ -0,0 +1 @@
+added confirming dependencies to ``uninstall`` command.

src/pip/_internal/commands/uninstall.py

@@ -5,6 +5,7 @@
 from pip._internal.basecommand import Command
 from pip._internal.exceptions import InstallationError
 from pip._internal.req import InstallRequirement, parse_requirements
+from pip._internal.utils.misc import confirm_dependencies
 from pip._internal.utils.misc import protect_pip_from_modification_on_windows
 
 
@@ -65,6 +66,8 @@ def run(self, options, args):
                     '"pip help %(name)s")' % dict(name=self.name)
                 )
 
+            if not confirm_dependencies(reqs_to_uninstall):
+                return
             protect_pip_from_modification_on_windows(
                 modifying_pip="pip" in reqs_to_uninstall
             )

src/pip/_internal/utils/misc.py

@@ -19,6 +19,7 @@
 from collections import deque
 
 from pip._vendor import pkg_resources
+from pip._vendor.packaging.utils import canonicalize_name
 # NOTE: retrying is not annotated in typeshed as on 2017-07-17, which is
 #       why we ignore the type on this import.
 from pip._vendor.retrying import retry  # type: ignore
@@ -854,6 +855,34 @@ def enum(*sequential, **named):
     return type('Enum', (), enums)
 
 
+def confirm_dependencies(reqs_to_uninstall):
+    depends = list(get_depends(reqs_to_uninstall))
+    if not depends:
+        return True
+
+    for d, deps in depends:
+        msg = ("The following packages depend on "
+               "%s and may break if it is uninstalled:") % d
+        logger.info(msg)
+        for dep in deps:
+            logger.info(" " + dep)
+
+    return ask("uninstall? (y/n)", options=('y', 'n')) == 'y'
+
+
+def get_depends(reqs_to_uninstall):
+    dist_deps = {d.key: [canonicalize_name(r.name) for r in d.requires()]
+                 for d in get_installed_distributions()}
+    logger.debug('dist_deps %s', dist_deps)
+    dependants = {req: [d for d, r in dist_deps.items() if req in r]
+                  for req in reqs_to_uninstall}
+    logger.debug('dependants %s', dependants)
+    for d, deps in dependants.items():
+        deps = [r for r in deps if r not in reqs_to_uninstall]
+        if deps:
+            yield d, deps
+
+
 def remove_auth_from_url(url):
     # Return a copy of url with 'username:password@' removed.
     # username/pass params are passed to subversion through flags

tests/functional/dummy1/setup.cfg

@@ -0,0 +1,2 @@
+[bdist_wheel]
+universal = 1

tests/functional/dummy1/setup.py

@@ -0,0 +1,6 @@
+from setuptools import setup
+setup(
+    name="dummy1",
+    install_requires=["dummy2"],
+    packages=["dummy1"],
+)

tests/functional/dummy2/setup.cfg

@@ -0,0 +1,2 @@
+[bdist_wheel]
+universal = 1

tests/functional/dummy2/setup.py

@@ -0,0 +1,6 @@
+from setuptools import setup
+setup(
+    name="dummy2",
+    install_requires=["dummy1"],
+    packages=["dummy2"],
+)

tests/functional/test_uninstall.py

@@ -144,13 +144,97 @@ def test_basic_uninstall_namespace_package(script):
     assert join(script.site_packages, 'pd') in result.files_created, (
         sorted(result.files_created.keys())
     )
-    result2 = script.pip('uninstall', 'pd.find', '-y', expect_error=True)
+    result2 = script.pip('uninstall', 'pd.requires', '-y', expect_error=True)
     assert join(script.site_packages, 'pd') not in result2.files_deleted, (
         sorted(result2.files_deleted.keys())
     )
+    pd_requires_path = join(script.site_packages, 'pd', 'requires')
+    assert pd_requires_path in result2.files_deleted, (
+        sorted(result2.files_deleted.keys())
+    )
+
+
+@pytest.mark.network
+def test_uninstall_dependency(script):
+    """
+    Uninstall a distribution depended from other, answer `y` to confirmation.
+
+    """
+    result = script.pip('install', 'pd.requires==0.0.3', expect_error=True)
+    assert join(script.site_packages, 'pd') in result.files_created, (
+        sorted(result.files_created.keys())
+    )
+    result2 = script.pip('uninstall', 'pd.find', '-y',
+                         expect_error=True, stdin=b"y")
+    assert join(script.site_packages, 'pd') not in result2.files_deleted, (
+        sorted(result2.files_deleted.keys())
+    )
+    assert join(script.site_packages, 'pd', 'find') in result2.files_deleted, (
+        sorted(result2.files_deleted.keys())
+    )
+
+
+@pytest.mark.network
+def test_uninstall_dependency_no(script):
+    """
+    Not uninstalling, answer `no` to confirmation.
+
+    """
+    result = script.pip('install', 'pd.requires==0.0.3', expect_error=True)
+    assert join(script.site_packages, 'pd') in result.files_created, (
+        sorted(result.files_created.keys())
+    )
+    result2 = script.pip('uninstall', 'pd.find', '-y',
+                         expect_error=True, stdin=b"n")
+    assert not result2.files_deleted
+
+
+@pytest.mark.network
+def test_uninstall_dependency_all(script):
+    """
+    Uninstall all dependencies, no confirmation.
+    """
+    result = script.pip('install', 'pd.requires==0.0.3', expect_error=True)
+    assert join(script.site_packages, 'pd') in result.files_created, (
+        sorted(result.files_created.keys())
+    )
+    result2 = script.pip('uninstall', 'pd.requires', 'pd.find', '-y',
+                         expect_error=True, stdin=b"y")
     assert join(script.site_packages, 'pd', 'find') in result2.files_deleted, (
         sorted(result2.files_deleted.keys())
     )
+    pd_requires_path = join(script.site_packages, 'pd', 'requires')
+    assert pd_requires_path in result2.files_deleted, (
+        sorted(result2.files_deleted.keys())
+    )
+    assert join(script.site_packages, 'pd') in result2.files_deleted, (
+        sorted(result2.files_deleted.keys())
+    )
+
+
+@pytest.mark.network
+def test_uninstall_recursive_dependencies(script):
+    """
+    Uninstall recursive dependencies.
+    """
+    here = os.path.normpath(os.path.abspath(os.path.dirname(__file__)))
+    dummy1_whl = os.path.join(here, "dummy1-0.0.0-py2.py3-none-any.whl")
+    dummy2_whl = os.path.join(here, "dummy2-0.0.0-py2.py3-none-any.whl")
+    result = script.pip('install', dummy1_whl, dummy2_whl, expect_error=True)
+    assert join(script.site_packages, 'dummy1') in result.files_created, (
+        sorted(result.files_created.keys())
+    )
+    assert join(script.site_packages, 'dummy2') in result.files_created, (
+        sorted(result.files_created.keys())
+    )
+    result2 = script.pip('uninstall', 'dummy1', 'dummy2', '-y',
+                         expect_error=True, stdin=b"y")
+    assert join(script.site_packages, 'dummy1') in result2.files_deleted, (
+        sorted(result2.files_deleted.keys())
+    )
+    assert join(script.site_packages, 'dummy2') in result2.files_deleted, (
+        sorted(result2.files_deleted.keys())
+    )
 
 
 def test_uninstall_overlapping_package(script, data):

tests/unit/test_utils.py

@@ -14,11 +14,13 @@
 
 import pytest
 from mock import Mock, patch
+from pip._vendor.packaging.requirements import Requirement
 from pip._vendor.six import BytesIO
 
 from pip._internal.exceptions import (
     HashMismatch, HashMissing, InstallationError, UnsupportedPythonVersion,
 )
+from pip._internal.req.req_install import InstallRequirement
 from pip._internal.utils.encoding import auto_decode
 from pip._internal.utils.glibc import check_glibc_version
 from pip._internal.utils.hashes import Hashes, MissingHashes
@@ -595,6 +597,35 @@ def test_check_requires(self, metadata, should_raise):
             check_dist_requires_python(fake_dist)
 
 
+@patch('pip._internal.utils.misc.ask')
+@patch('pip._internal.utils.misc.get_installed_distributions')
+def test_confirm_dependencies(mock_gid, mock_ask):
+    from pip._internal.utils.misc import confirm_dependencies
+
+    class installed:
+        def __init__(self, key, requires):
+            self.key = key
+            self._requires = requires
+
+        def requires(self):
+            return self._requires
+
+    class installed_require:
+        def __init__(self, name):
+                self.name = name
+
+    installed_packages = [
+        installed('dependant',
+                  [InstallRequirement(Requirement("dummy"), None)]),
+    ]
+    mock_gid.return_value = installed_packages
+    mock_ask.return_value = 'y'
+
+    reqs_to_uninstall = ["dummy"]
+    result = confirm_dependencies(reqs_to_uninstall)
+    assert result
+
+
 class TestGetProg(object):
 
     @pytest.mark.parametrize(