PyDict_Next should not lock the dict

@DinoV

Bug report

PyDict_Next currently wraps _PyDict_Next in a critical section. We shouldn't do this -- the locking needs to be external to the call.

It's not sufficient to lock the dict just for each _PyDict_Next call because we return borrowed references and because pos becomes meaningless if the dictionary gets resized or rehashed.
It interferes with externally locking the dict because the inner critical sections can suspend the outer ones. In other words, if the caller use a critical section to lock the dict for multiple iterations, this will break that.

cpython/Objects/dictobject.c

Lines 2883 to 2890 in 8f17d69

    
           PyDict_Next(PyObject *op, Py_ssize_t *ppos, PyObject **pkey, PyObject **pvalue) 
        
           { 
        
               int res; 
        
               Py_BEGIN_CRITICAL_SECTION(op); 
        
               res = _PyDict_Next(op, ppos, pkey, pvalue, NULL); 
        
               Py_END_CRITICAL_SECTION(); 
        
               return res; 
        
           }

cc @DinoV

Linked PRs

pythongh-120858: PyDict_Next should not lock the dict

gh-120858: PyDict_Next should not lock the dict (#120859)

pythongh-120858: PyDict_Next should not lock the dict (pythonGH-120859)

[3.13] gh-120858: PyDict_Next should not lock the dict (GH-120859) (#…

pythongh-120858: PyDict_Next should not lock the dict (python#120859)

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`PyDict_Next` should not lock the dict #120858

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	PyDict_Next(PyObject op, Py_ssize_t ppos, PyObject pkey, PyObject pvalue)
	{
	int res;
	Py_BEGIN_CRITICAL_SECTION(op);
	res = _PyDict_Next(op, ppos, pkey, pvalue, NULL);
	Py_END_CRITICAL_SECTION();
	return res;
	}

PyDict_Next should not lock the dict #120858

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`PyDict_Next` should not lock the dict #120858