Explicitly require Python 3.10+ for vendoring task

Author: sethmlarson

noxfile.py

@@ -184,6 +184,12 @@ def lint(session: nox.Session) -> None:
 # git reset --hard origin/main
 @nox.session
 def vendoring(session: nox.Session) -> None:
+    # Ensure that the session Python is running 3.10+
+    # so that truststore can be installed correctly.
+    session.run(
+        "python", "-c", "import sys; sys.exit(1 if sys.version_info < (3, 10) else 0)"
+    )
+
     session.install("vendoring~=1.2.0")
 
     parser = argparse.ArgumentParser(prog="nox -s vendoring")

src/pip/_internal/cli/req_command.py

@@ -60,9 +60,7 @@ def _create_truststore_ssl_context() -> Optional["SSLContext"]:
     try:
         from pip._vendor import truststore
     except ImportError as e:
-        raise CommandError(
-            f"The truststore feature is unavailable: {e}"
-        )
+        raise CommandError(f"The truststore feature is unavailable: {e}")
 
     return truststore.SSLContext(ssl.PROTOCOL_TLS_CLIENT)