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, 9 insertions, 0 deletions

diff --git a/Mac/Tools/pythonw.c b/Mac/Tools/pythonw.c
index 1d2db38..c8bd3ba 100644
--- a/Mac/Tools/pythonw.c
+++ b/Mac/Tools/pythonw.c
@@ -196,6 +196,15 @@ main(int argc, char **argv) {
             }
         }
 
+        /*
+         * The environment variable is used to pass the value of real_path
+         * to the actual python interpreter, and is read by code in
+         * Python/coreconfig.c.
+         *
+         * This way the real interpreter knows how the user invoked the
+         * interpreter and can behave as if this launcher is the real
+         * interpreter (looking for pyvenv configuration, ...)
+         */
         setenv("__PYVENV_LAUNCHER__", real_path, 1);
     }