bpo-22490: Remove __PYVENV_LAUNCHER__ from environment during launch (GH-9516)

* bpo-22490: Remove "__PYVENV_LAUNCHER__" from the shell environment on macOS

This changeset removes the environment varialbe "__PYVENV_LAUNCHER__"
during interpreter launch as it is only needed to communicate between
the stub executable in framework installs and the actual interpreter.

Leaving the environment variable present may lead to misbehaviour when
launching other scripts.

* Actually commit the changes for issue 22490...

* Correct typo

Co-Authored-By: Nicola Soranzo <nicola.soranzo@gmail.com>

* Run make patchcheck

Co-authored-by: Jason R. Coombs <jaraco@jaraco.com>
Co-authored-by: Nicola Soranzo <nicola.soranzo@gmail.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/Python/initconfig.c b/Python/initconfig.c
index 19070d2a3f..7bad36ef17 100644
--- a/Python/initconfig.c
+++ b/Python/initconfig.c
@@ -1139,6 +1139,17 @@ config_init_program_name(PyConfig *config)
             if (_PyStatus_EXCEPTION(status)) {
                 return status;
             }
+
+            /*
+             * This environment variable is used to communicate between
+             * the stub launcher and the real interpreter and isn't needed
+             * beyond this point.
+             *
+             * Clean up to avoid problems when launching other programs
+             * later on.
+             */
+            (void)unsetenv("__PYVENV_LAUNCHER__");
+
             return _PyStatus_OK();
         }
     }