From 2c3f3a590ddfc151a456b44a5f96f0f603d178e9 Mon Sep 17 00:00:00 2001
From: Lumir Balhar <lbalhar@redhat.com>
Date: Wed, 16 Feb 2022 08:36:21 +0100
Subject: [PATCH] Prevent removing of the system packages installed under
 /usr/lib when pip install --upgrade is executed.
MIME-Version: 1.0
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Resolves: rhbz#1550368

Co-Authored-By: Michal Cyprian <m.cyprian@gmail.com>
Co-Authored-By: Victor Stinner <vstinner@redhat.com>
Co-Authored-By: Petr Viktorin <pviktori@redhat.com>
Co-Authored-By: Lumir Balhar <lbalhar@redhat.com>
Co-Authored-By: Miro Hrončok <miro@hroncok.cz>
Co-Authored-By: Karolina Surma <ksurma@redhat.com>
---
 src/pip/_internal/metadata/base.py                 | 12 +++++++++++-
 src/pip/_internal/req/req_install.py               |  2 +-
 src/pip/_internal/resolution/legacy/resolver.py    |  4 +++-
 src/pip/_internal/resolution/resolvelib/factory.py | 12 ++++++++++++
 4 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/src/pip/_internal/metadata/base.py b/src/pip/_internal/metadata/base.py
index 151fd6d..f9109cd 100644
--- a/src/pip/_internal/metadata/base.py
+++ b/src/pip/_internal/metadata/base.py
@@ -28,7 +28,7 @@ from pip._vendor.packaging.utils import NormalizedName
 from pip._vendor.packaging.version import LegacyVersion, Version
 
 from pip._internal.exceptions import NoneMetadataError
-from pip._internal.locations import site_packages, user_site
+from pip._internal.locations import get_scheme, site_packages, user_site
 from pip._internal.models.direct_url import (
     DIRECT_URL_METADATA_NAME,
     DirectUrl,
@@ -560,6 +560,16 @@ class BaseDistribution(Protocol):
             for extra in self._iter_egg_info_extras():
                 metadata["Provides-Extra"] = extra
 
+    @property
+    def in_install_path(self) -> bool:
+        """
+        Return True if given Distribution is installed in
+        path matching distutils_scheme layout.
+        """
+        norm_path = normalize_path(self.installed_location)
+        return norm_path.startswith(normalize_path(
+            get_scheme("").purelib.split('python')[0]))
+
 
 class BaseEnvironment:
     """An environment containing distributions to introspect."""
diff --git a/src/pip/_internal/req/req_install.py b/src/pip/_internal/req/req_install.py
index a1e376c..ed7facf 100644
--- a/src/pip/_internal/req/req_install.py
+++ b/src/pip/_internal/req/req_install.py
@@ -416,7 +416,7 @@ class InstallRequirement:
                         f"lack sys.path precedence to {existing_dist.raw_name} "
                         f"in {existing_dist.location}"
                     )
-            else:
+            elif existing_dist.in_install_path:
                 self.should_reinstall = True
         else:
             if self.editable:
diff --git a/src/pip/_internal/resolution/legacy/resolver.py b/src/pip/_internal/resolution/legacy/resolver.py
index fb49d41..040f2c1 100644
--- a/src/pip/_internal/resolution/legacy/resolver.py
+++ b/src/pip/_internal/resolution/legacy/resolver.py
@@ -325,7 +325,9 @@ class Resolver(BaseResolver):
         """
         # Don't uninstall the conflict if doing a user install and the
         # conflict is not a user install.
-        if not self.use_user_site or req.satisfied_by.in_usersite:
+        if ((not self.use_user_site
+                or req.satisfied_by.in_usersite)
+                and req.satisfied_by.in_install_path):
             req.should_reinstall = True
         req.satisfied_by = None
 
diff --git a/src/pip/_internal/resolution/resolvelib/factory.py b/src/pip/_internal/resolution/resolvelib/factory.py
index a4c24b5..e7e2da9 100644
--- a/src/pip/_internal/resolution/resolvelib/factory.py
+++ b/src/pip/_internal/resolution/resolvelib/factory.py
@@ -1,6 +1,8 @@
 import contextlib
 import functools
 import logging
+import sys
+import sysconfig
 from typing import (
     TYPE_CHECKING,
     Dict,
@@ -549,6 +551,16 @@ class Factory:
         if dist is None:  # Not installed, no uninstallation required.
             return None
 
+        # Prevent uninstalling packages from /usr
+        try:
+            if dist.installed_location in (
+                    sysconfig.get_path('purelib', scheme='posix_prefix', vars={'base': sys.base_prefix}),
+                    sysconfig.get_path('platlib', scheme='posix_prefix', vars={'platbase': sys.base_prefix}),
+            ):
+                return None
+        except KeyError:  # this Python doesn't have 'rpm_prefix' scheme yet
+            pass
+
         # We're installing into global site. The current installation must
         # be uninstalled, no matter it's in global or user site, because the
         # user site installation has precedence over global.
-- 
2.35.3