[PATCH] libgpiod: bindings: python: Fix PyDict_Next contiguous assumption and pypy

[George Harker <george@xxxxxxxxxxxxxxxxxxxxx>]

PyDict_Next does not guarantee pos is contiguous, and pypy increments
past the end of the dict size.  Patch fixes reliance on pos for constructing
args for gpiod call.

As per discussion here https://github.com/pypy/pypy/issues/5142

---
 bindings/python/gpiod/ext/request.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/bindings/python/gpiod/ext/request.c b/bindings/python/gpiod/ext/request.c
index e1a2a42..4e49289 100644
--- a/bindings/python/gpiod/ext/request.c
+++ b/bindings/python/gpiod/ext/request.c
@@ -206,6 +206,7 @@ static PyObject *request_set_values(request_object *self, PyObject *args)
 {
 	PyObject *values, *key, *val, *val_stripped;
 	Py_ssize_t pos = 0;
+	Py_ssize_t index = 0;
 	int ret;
 
 	ret = PyArg_ParseTuple(args, "O", &values);
@@ -214,8 +215,10 @@ static PyObject *request_set_values(request_object *self, PyObject *args)
 
 	clear_buffers(self);
 
+	// Note: pos may not be contiguous and in pypy, is incremented
+	// past the end of the dict size.
 	while (PyDict_Next(values, &pos, &key, &val)) {
-		self->offsets[pos - 1] = Py_gpiod_PyLongAsUnsignedInt(key);
+		self->offsets[index] = Py_gpiod_PyLongAsUnsignedInt(key);
 		if (PyErr_Occurred())
 			return NULL;
 
@@ -223,15 +226,17 @@ static PyObject *request_set_values(request_object *self, PyObject *args)
 		if (!val_stripped)
 			return NULL;
 
-		self->values[pos - 1] = PyLong_AsLong(val_stripped);
+		self->values[index] = PyLong_AsLong(val_stripped);
 		Py_DECREF(val_stripped);
 		if (PyErr_Occurred())
 			return NULL;
+
+		index += 1;
 	}
 
 	Py_BEGIN_ALLOW_THREADS;
 	ret = gpiod_line_request_set_values_subset(self->request,
-						   pos,
+						   index,
 						   self->offsets,
 						   self->values);
 	Py_END_ALLOW_THREADS;
-- 
2.39.5