Fixes issues 3883 and 5194

1 files changed, 50 insertions, 7 deletions

diff --git a/Mac/IDLE/idlemain.py b/Mac/IDLE/idlemain.py
index 9b52738..d6803ba 100644
--- a/Mac/IDLE/idlemain.py
+++ b/Mac/IDLE/idlemain.py
@@ -3,8 +3,6 @@ Bootstrap script for IDLE as an application bundle.
 """
 import sys, os
 
-from idlelib.PyShell import main
-
 # Change the current directory the user's home directory, that way we'll get
 # a more useful default location in the open/save dialogs.
 os.chdir(os.path.expanduser('~/Documents'))
@@ -13,10 +11,54 @@ os.chdir(os.path.expanduser('~/Documents'))
 # Make sure sys.executable points to the python interpreter inside the
 # framework, instead of at the helper executable inside the application
 # bundle (the latter works, but doesn't allow access to the window server)
-if sys.executable.endswith('-32'):
-    sys.executable = os.path.join(sys.prefix, 'bin', 'python-32')
-else:
-    sys.executable = os.path.join(sys.prefix, 'bin', 'python')
+#
+#  .../IDLE.app/
+#       Contents/
+#           MacOS/
+#               IDLE (a python script)
+#               Python{-32} (symlink)
+#           Resources/
+#               idlemain.py (this module)
+#               ...
+#
+# ../IDLE.app/Contents/MacOS/Python{-32} is symlinked to
+#       ..Library/Frameworks/Python.framework/Versions/m.n
+#                   /Resources/Python.app/Contents/MacOS/Python{-32}
+#       which is the Python interpreter executable
+#
+# The flow of control is as follows:
+# 1. IDLE.app is launched which starts python running the IDLE script
+# 2. IDLE script exports
+#       PYTHONEXECUTABLE = .../IDLE.app/Contents/MacOS/Python{-32}
+#           (the symlink to the framework python)
+# 3. IDLE script alters sys.argv and uses os.execve to replace itself with
+#       idlemain.py running under the symlinked python.
+#       This is the magic step.
+# 4. During interpreter initialization, because PYTHONEXECUTABLE is defined,
+#    sys.executable may get set to an unuseful value.
+#
+# (Note that the IDLE script and the setting of PYTHONEXECUTABLE is
+#  generated automatically by bundlebuilder in the Python 2.x build.
+#  Also, IDLE invoked via command line, i.e. bin/idle, bypasses all of
+#  this.)
+#
+# Now fix up the execution environment before importing idlelib.
+
+# Reset sys.executable to its normal value, the actual path of
+# the interpreter in the framework, by following the symlink
+# exported in PYTHONEXECUTABLE.
+pyex = os.environ['PYTHONEXECUTABLE']
+sys.executable = os.path.join(os.path.dirname(pyex), os.readlink(pyex))
+
+# Remove any sys.path entries for the Resources dir in the IDLE.app bundle.
+p = pyex.partition('.app')
+if p[2].startswith('/Contents/MacOS/Python'):
+    sys.path = [value for value in sys.path if
+            value.partition('.app') != (p[0], p[1], '/Contents/Resources')]
+
+# Unexport PYTHONEXECUTABLE so that the other Python processes started
+# by IDLE have a normal sys.executable.
+del os.environ['PYTHONEXECUTABLE']
 
 # Look for the -psn argument that the launcher adds and remove it, it will
 # only confuse the IDLE startup code.
@@ -25,6 +67,7 @@ for idx, value in enumerate(sys.argv):
         del sys.argv[idx]
         break
 
-#argvemulator.ArgvCollector().mainloop()
+# Now it is safe to import idlelib.
+from idlelib.PyShell import main
 if __name__ == '__main__':
     main()