possible memory leak in sage.matrix.matrix_integer_dense

[burcin]

    def __dealloc__(self):
        """
        Frees all the memory allocated for this matrix. 
        EXAMPLE:
            sage: a = Matrix(ZZ,2,[1,2,3,4])
            sage: del a        
        """
        cdef Py_ssize_t i
        if self._initialized:
            for i from 0 <= i < (self._nrows * self._ncols):
                mpz_clear(self._entries[i])
            sage_free(self._entries)
            sage_free(self._matrix)

It is possible that _initialized is not set but _matrix and _entries are allocated.

Error paths in __new__ and __init__ should also be revised, since if one raises an error in these functions python still calls __dealloc__ for the cleanup.

From the __init__ function:

        elif isinstance(entries, (int,long)) or is_Element(entries):
            try:
                x = ZZ(entries)
            except TypeError:
                self._initialized = False
                raise TypeError, "unable to coerce entry to an integer"

Component: memleak

Issue created by migration from https://trac.sagemath.org/ticket/4883