From cf7183d8757dd05c36f0d8bccbf385fc195e775e Mon Sep 17 00:00:00 2001
From: Jon Dufresne <jon.dufresne@gmail.com>
Date: Sun, 8 Aug 2021 09:44:15 -0700
Subject: [PATCH] Remove six import from src/pip/_internal/req/req_install.py

Use Python 3 `raise exc from ...` semantics to replace the use of
six.reraise.
---
 news/ecb79d5a-46b6-4e7b-8ee8-561c9aac697b.vendor.rst | 0
 src/pip/_internal/operations/install/legacy.py       | 8 +++-----
 src/pip/_internal/req/req_install.py                 | 4 ++--
 3 files changed, 5 insertions(+), 7 deletions(-)
 create mode 100644 news/ecb79d5a-46b6-4e7b-8ee8-561c9aac697b.vendor.rst

diff --git a/news/ecb79d5a-46b6-4e7b-8ee8-561c9aac697b.vendor.rst b/news/ecb79d5a-46b6-4e7b-8ee8-561c9aac697b.vendor.rst
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/src/pip/_internal/operations/install/legacy.py b/src/pip/_internal/operations/install/legacy.py
index b7d4301c370..b7abdd4d04e 100644
--- a/src/pip/_internal/operations/install/legacy.py
+++ b/src/pip/_internal/operations/install/legacy.py
@@ -3,7 +3,6 @@
 
 import logging
 import os
-import sys
 from distutils.util import change_root
 from typing import List, Optional, Sequence
 
@@ -20,8 +19,7 @@
 
 
 class LegacyInstallFailure(Exception):
-    def __init__(self) -> None:
-        self.parent = sys.exc_info()
+    pass
 
 
 def write_installed_files_from_setuptools_record(
@@ -111,9 +109,9 @@ def install(
                 # Signal to the caller that we didn't install the new package
                 return False
 
-        except Exception:
+        except Exception as e:
             # Signal to the caller that we didn't install the new package
-            raise LegacyInstallFailure
+            raise LegacyInstallFailure from e
 
         # At this point, we have successfully installed the requirement.
 
diff --git a/src/pip/_internal/req/req_install.py b/src/pip/_internal/req/req_install.py
index 615535f24b6..add22b552cf 100644
--- a/src/pip/_internal/req/req_install.py
+++ b/src/pip/_internal/req/req_install.py
@@ -9,7 +9,7 @@
 import zipfile
 from typing import Any, Dict, Iterable, List, Optional, Sequence, Union
 
-from pip._vendor import pkg_resources, six
+from pip._vendor import pkg_resources
 from pip._vendor.packaging.markers import Marker
 from pip._vendor.packaging.requirements import Requirement
 from pip._vendor.packaging.specifiers import SpecifierSet
@@ -795,7 +795,7 @@ def install(
             )
         except LegacyInstallFailure as exc:
             self.install_succeeded = False
-            six.reraise(*exc.parent)
+            raise exc.__cause__
         except Exception:
             self.install_succeeded = True
             raise