[Pyobjc-dev] Debugging Tips

[Bill B. <bb...@co...>]

I'm trying to track down the segfault that occurs after the third or 
fourth NSArray/NSDictionary is created.   Bad bug.  Trashes the stack.  
Very hard to figure out (at least for me).

Some random tips...

- You can run the tests under gdb in project builder.... this gives 
access to the handy dandy PBX debugging GUI.

     Create a new foundation tool project

     Delete the source and frameworks... everything but the product.

     Add a custom executable.  Set the executable to /usr/bin/python.

     Add an argument.  Set it to the path to one of the unit testing 
scripts (or whatever).

     Click the debug icon.....

That's it!

Now, to break somewhere in the bridge, you probably don't want to set 
any old breakpoint.  More likely, you want to set the breakpoints that 
you want, then disable them, then set a single breakpoint that will be 
hit after module initialization.   To do this, I chose some random 
debugging function that is relatively innocuous that I could call from 
the python code.

Specifically....

class TestNSArrayInteraction( unittest.TestCase ):
     def testNSArrayAllocation( self ):
         NSCountFrames()
         for i in range(1,1000):
             print "c: %s" % i
             a = NSArray.array()
             b = NSArray.alloc().init()

.... I chose NSCountFrames().  In gdb, I set a breakpoint on 
NSCountFrames().  When the breakpoint is hit, simply enable the  real 
breakpoints and continue execution.

Works for me, anyway.