fix regression in Darwin 19 (OSX 10.15+) ansible python interpreter detection

mitogen/parent.py

@@ -42,6 +42,7 @@ import heapq
 import inspect
 import logging
 import os
+import platform
 import re
 import signal
 import socket
@@ -1434,7 +1435,10 @@ class Connection(object):
             os.close(r)
             os.close(W)
             os.close(w)
-            if sys.platform == 'darwin' and sys.executable == '/usr/bin/python':
+            # this doesn't apply anymore to Mac OSX 10.15+ (Darwin 19+), new interpreter looks like this:
+            # /System/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python
+            if sys.platform == 'darwin' and sys.executable == '/usr/bin/python' and \
+                    int(platform.release()[:2]) < 19:
                 sys.executable += sys.version[:3]
             os.environ['ARGV0']=sys.executable
             os.execl(sys.executable,sys.executable+'(mitogen:CONTEXT_NAME)')

tests/ansible/lib/modules/test_echo_module.py

@@ -9,6 +9,7 @@
 from __future__ import absolute_import, division, print_function
 __metaclass__ = type
 
+import platform
 import sys
 from ansible.module_utils.basic import AnsibleModule
 
@@ -23,7 +24,12 @@ def main():
     result['ansible_facts'] = module.params['facts']
     # revert the Mitogen OSX tweak since discover_interpreter() doesn't return this info
     if sys.platform == 'darwin' and sys.executable != '/usr/bin/python':
-        sys.executable = sys.executable[:-3]
+        if int(platform.release()[:2]) < 19:
+            sys.executable = sys.executable[:-3]
+        else:
+            # only for tests to check version of running interpreter -- Mac 10.15+ changed python2
+            # so it looks like it's /usr/bin/python but actually it's /System/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python
+            sys.executable = "/usr/bin/python"
     result['running_python_interpreter'] = sys.executable
 
     module.exit_json(**result)