A script to fix Apple-installed Python 2.3 (and a test whether the user

needs to run it in the Makefile).

After installing a newer framework Python the apple-installed Python can
no longer build extension modules, because they will inadvertantly be linked
against the newer framework. This script modifies lib/config/Makefile so
it will link extensions with "-undefined dynamic_lookup", which forestalls
this problem.

Will backport to 2.4 and 2.3.

Mac/OSX/Makefile

@@ -60,7 +60,7 @@ compileall=$(srcdir)/Lib/compileall.py
 bundlebuilder=$(srcdir)/Lib/plat-mac/bundlebuilder.py
 
 installapps: install_PythonLauncher install_Python install_BuildApplet install_IDE \
-	install_IDLE install_PackageManager
+	install_IDLE install_PackageManager checkapplepython
 
 install_PythonLauncher:
 	cd $(srcdir)/Mac/OSX/PythonLauncher/PythonLauncher.pbproj ; \
@@ -257,3 +257,10 @@ installextras:
 		$(DESTDIR)$(PYTHONAPPSDIR)/Extras/Demo
 	$(BUILDPYTHON) $(srcdir)/Mac/OSX/Extras.install.py $(srcdir)/Tools \
 		$(DESTDIR)$(PYTHONAPPSDIR)/Extras/Tools
+
+checkapplepython:
+	@if ! $(BUILDPYTHON) $(srcdir)/Mac/OSX/fixapplepython23.py -n; then \
+		echo "* WARNING: Apple-installed Python 2.3 will have trouble building extensions from now on."; \
+		echo "* WARNING: Run $(srcdir)/Mac/OSX/fixapplepython23.py with \"sudo\" to fix this."; \
+	fi
+    

Mac/OSX/fixapplepython23.py

@@ -0,0 +1,95 @@
+"""fixapplepython23 - Fix Apple-installed Python 2.3 (on Mac OS X 10.3)
+
+Python 2.3 (and 2.3.X for X<5) have the problem that building an extension
+for a framework installation may accidentally pick up the framework
+of a newer Python, in stead of the one that was used to build the extension.
+
+This script modifies the Makefile (in .../lib/python2.3/config) to use
+the newer method of linking extensions with "-undefined dynamic_lookup"
+which fixes this problem.
+
+The script will first check all prerequisites, and return a zero exit
+status also when nothing needs to be fixed.
+"""
+import sys
+import os
+import gestalt
+
+MAKEFILE='/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/config/Makefile'
+OLD_LDSHARED='LDSHARED=\t$(CC) $(LDFLAGS) -bundle -framework $(PYTHONFRAMEWORK)\n'
+OLD_BLDSHARED='B' + OLD_LDSHARED
+NEW_LDSHARED='LDSHARED=\t$(CC) $(LDFLAGS) -bundle -undefined dynamic_lookup\n'
+NEW_BLDSHARED='B' + NEW_LDSHARED
+
+def findline(lines, start):
+    """return line starting with given string or -1"""
+    for i in range(len(lines)):
+        if lines[i][:len(start)] == start:
+            return i
+    return -1
+    
+def fix(makefile, do_apply):
+    """Fix the Makefile, if required."""
+    fixed = False
+    lines = open(makefile).readlines()
+    
+    i = findline(lines, 'LDSHARED=')
+    if i < 0:
+        print 'fixapplepython23: Python installation not fixed (appears broken, no LDSHARED)'
+        return 2
+    if lines[i] == OLD_LDSHARED:
+        lines[i] = NEW_LDSHARED
+        fixed = True
+    elif lines[i] != NEW_LDSHARED:
+        print 'fixapplepython23: Python installation not fixed (appears modified, unexpected LDSHARED)'
+        return 2
+        
+    i = findline(lines, 'BLDSHARED=')
+    if i < 0:
+        print 'fixapplepython23: Python installation not fixed (appears broken, no BLDSHARED)'
+        return 2
+    if lines[i] == OLD_BLDSHARED:
+        lines[i] = NEW_BLDSHARED
+        fixed = True
+    elif lines[i] != NEW_BLDSHARED:
+        print 'fixapplepython23: Python installation not fixed (appears modified, unexpected BLDSHARED)'
+        return 2
+        
+    if fixed:
+        if do_apply:
+            print 'fixapplepython23: Fix to Apple-installed Python 2.3 applied'
+            os.rename(makefile, makefile + '~')
+            open(makefile, 'w').writelines(lines)
+            return 0
+        else:
+            print 'fixapplepython23: Fix to Apple-installed Python 2.3 should be applied'
+            return 1
+    else:
+        print 'fixapplepython23: No fix needed, appears to have been applied before'
+        return 0
+        
+def main():
+    # Check for -n option
+    if len(sys.argv) > 1 and sys.argv[1] == '-n':
+        do_apply = False
+    else:
+        do_apply = True
+    # First check OS version
+    if gestalt.gestalt('sysv') < 0x1030:
+        print 'fixapplepython23: no fix needed on MacOSX < 10.3'
+        sys.exit(0)
+    # Test that a framework Python is indeed installed
+    if not os.path.exists(MAKEFILE):
+        print 'fixapplepython23: Python framework does not appear to be installed (?), nothing fixed'
+        sys.exit(0)
+    # Check that we can actually write the file
+    if do_apply and not os.access(MAKEFILE, os.W_OK):
+        print 'fixapplepython23: No write permission, please run with "sudo"'
+        sys.exit(2)
+    # And finally fix it
+    rv = fix(MAKEFILE, do_apply)
+    sys.exit(rv)
+    
+if __name__ == '__main__':
+    main()
+