[Swig-devel] [ swig-Bugs-1981315 ] Infinite recursion with cross-module inheritance

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Bugs item #1981315, was opened at 2008-06-01 15:51
Message generated for change (Comment added) made by paulmelis
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Category: python
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Paul E.C. Melis (paulmelis)
Assigned to: Nobody/Anonymous (nobody)
Summary: Infinite recursion with cross-module inheritance

Initial Comment:
Given:
- two modules, mod1 and mod2, meant for wrapping in Python
- mod1 contains a C++ class Base
- mod2 contains a class Derived, which is derived from Base
- directors enabled for both classes
- directors enabled for both modules
- the following C++ code:

class Base
{
public:
    virtual void do_something() { printf("Base::do_something()\n"); }

    virtual ~Base() {}
};

class Derived: public Base
{
public:
    virtual ~Derived() {}
};

- the rest of the details in the attached tgz



The following test script results in an infinite recursion:

import sys

import mod1
import mod2

def traceit(frame, event, arg):
    if event == "line":
        lineno = frame.f_lineno
        filename = frame.f_globals["__file__"]
        print "%s, line %d" % (filename, lineno)
    return traceit

sys.settrace(traceit)

class MyBase(mod1.Base):
    def __init__(self):
        mod1.Base.__init__(self)

b = MyBase()
b.do_something()    # Succeeds

class MyDerived(mod2.Derived):
    def __init__(self):
        mod2.Derived.__init__(self)

d = MyDerived()
d.do_something()   # Fails

I've added the trace function, as the exception raised does not give the information on the infinite recursion. The line in question constantly being executed is mod1.py:64, which is

class Base(_object):
    ...
    def do_something(*args): return _mod1.Base_do_something(*args)        # <-----
    ....

It seems the call can't "cross over" into mod2, or something like that.

----------------------------------------------------------------------

>Comment By: Paul E.C. Melis (paulmelis)
Date: 2008-06-01 16:05

Message:
Logged In: YES 
user_id=548640
Originator: YES

This is with both 1.3.29 and 1.3.35, btw

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