pysqlite_cursor_fetchall currently has the following bit of code:

    /* just make sure we enter the loop */
    row = (PyObject*)Py_None;

    while (row) {
        row = pysqlite_cursor_iternext(self);
        if (row) {
            PyList_Append(list, row);
            Py_DECREF(row);
        }
    }

This can and should be rewritten as a for loop to avoid the unnecessary initialization to Py_None and the redundant if statement inside the loop.

pysqlite_cursor_fetchmany has the same problem.

You mean, something like

    while ((row = pysqlite_cursor_iternext(self))) {
            PyList_Append(list, row);
            Py_DECREF(row);
    }

? It's interesting that now we have walrus in Python, we see the opportunities for it in other languages. (In C, it's spelled (=).:)

You're right, that's even better. I forgot that the equals operator also returns the variable's new value. I just updated my pull request :-)

It seems you haven't read carefully what I've written. This way some compilers might emit warnings. Please read https://stackoverflow.com/questions/5476759/compiler-warning-suggest-parentheses-around-assignment-used-as-truth-value

Sorry about that, I didn't notice that GCC's -Wall option emits a warning about this. I just added the extra sets of parentheses.

New changeset 78c7183f470b60a39ac2dd0ad1a94d49d1e0b062 by Alex Henrie in branch 'master':
bpo-39496: Remove redundant checks from _sqlite/cursor.c (GH-18270)
https://github.com/python/cpython/commit/78c7183f470b60a39ac2dd0ad1a94d49d1e0b062