serprex / byteplay Goto Github PK

I haven't tested the py3 version, but on python 2, this breaks the stack size computation and results in a segmentation fault or an assertion failure if you happen to be running debug python.

The following code prints old stacksize = 2, new stacksize = 0, and then crashes.

def rebuild_function():
    import byteplay as B

    c = B.Code.from_code(func.func_code)
    code = c.to_code()

    args = code, func.func_globals, func.func_name, func.func_defaults, func.func_closure
    return types.FunctionType(*args)

def testfunc():
    return VALUE, ANOTHER

newfunc = rebuild_function(testfunc)

print "Orig stacksize: ", testfunc.func_code.co_stacksize
print "New stacksize: ", newfunc.func_code.co_stacksize

# crashes
newfunc()

The dis package has beed changed in Python 3.5: https://docs.python.org/3.5/library/dis.html
WITH_CLEANUP is now split into WITH_CLEANUP_START and WITH_CLEANUP_FINISH, hence byteplay can't be imported without a NameError in Python 3.5.

I encountered the 'closed' issue reported by @pwaller with Python 3.4. Stack size computation is broken (method '_compute_stacksize') and returns zero for every block of code I tried. As I mentioned in comment of original issue I tried to fix it (peterazmanov/byteplay). My changes stopped crashes, but the code requires further testing.

Running the 2to3 tool resulted in this addition:

•                   if jump>0xFFFF:raise NotImplementedError,"Extended jumps not implemented"
  

•                   if jump>0xFFFF:raise NotImplementedError("Extended jumps not implemented")
  

There were other changes it recommended, but this was the minimum necessary to get byteplay to be able to import without throwing an error.