6 files changed, 483 insertions, 195 deletions

diff --git a/source/blender/python/generic/idprop_py_api.c b/source/blender/python/generic/idprop_py_api.c
index 2e15b7b1413..5d6a7c578a2 100644
--- a/source/blender/python/generic/idprop_py_api.c
+++ b/source/blender/python/generic/idprop_py_api.c
@@ -43,6 +43,9 @@
 
 #include "python_utildefines.h"
 
+extern bool pyrna_id_FromPyObject(PyObject *obj, ID **id);
+extern PyObject *pyrna_id_CreatePyObject(ID *id);
+extern bool pyrna_id_CheckPyObject(PyObject *obj);
 
 /*********************** ID Property Main Wrapper Stuff ***************/
 
@@ -88,6 +91,11 @@ static PyObject *idprop_py_from_idp_group(ID *id, IDProperty *prop, IDProperty *
 	return (PyObject *)group;
 }
 
+static PyObject *idprop_py_from_idp_id(IDProperty *prop)
+{
+	return pyrna_id_CreatePyObject(prop->data.pointer);
+}
+
 static PyObject *idprop_py_from_idp_array(ID *id, IDProperty *prop)
 {
 	BPy_IDProperty *array = PyObject_New(BPy_IDProperty, &BPy_IDArray_Type);
@@ -148,6 +156,7 @@ PyObject *BPy_IDGroup_WrapData(ID *id, IDProperty *prop, IDProperty *parent)
 		case IDP_GROUP:    return idprop_py_from_idp_group(id, prop, parent);
 		case IDP_ARRAY:    return idprop_py_from_idp_array(id, prop);
 		case IDP_IDPARRAY: return idprop_py_from_idp_idparray(id, prop); /* this could be better a internal type */
+		case IDP_ID:       return idprop_py_from_idp_id(prop);
 		default: Py_RETURN_NONE;
 	}
 }
@@ -335,19 +344,9 @@ static char idp_sequence_type(PyObject *seq_fast)
 	return type;
 }
 
-/**
- * \note group can be a pointer array or a group.
- * assume we already checked key is a string.
- *
- * \return success.
- */
-bool BPy_IDProperty_Map_ValidateAndCreate(PyObject *name_obj, IDProperty *group, PyObject *ob)
+static const char *idp_try_read_name(PyObject *name_obj)
 {
-	IDProperty *prop = NULL;
-	IDPropertyTemplate val = {0};
-
-	const char *name;
-
+	const char *name = NULL;
 	if (name_obj) {
 		Py_ssize_t name_size;
 		name = _PyUnicode_AsStringAndSize(name_obj, &name_size);
@@ -356,168 +355,307 @@ bool BPy_IDProperty_Map_ValidateAndCreate(PyObject *name_obj, IDProperty *group,
 			PyErr_Format(PyExc_KeyError,
 			             "invalid id-property key, expected a string, not a %.200s",
 			             Py_TYPE(name_obj)->tp_name);
-			return false;
+			return NULL;
 		}
 
 		if (name_size > MAX_IDPROP_NAME) {
 			PyErr_SetString(PyExc_KeyError, "the length of IDProperty names is limited to 63 characters");
-			return false;
+			return NULL;
 		}
 	}
 	else {
 		name = "";
 	}
+	return name;
+}
 
-	if (PyFloat_Check(ob)) {
-		val.d = PyFloat_AsDouble(ob);
-		prop = IDP_New(IDP_DOUBLE, &val, name);
-	}
-	else if (PyLong_Check(ob)) {
-		val.i = _PyLong_AsInt(ob);
-		if (val.i == -1 && PyErr_Occurred()) {
-			return false;
-		}
-		prop = IDP_New(IDP_INT, &val, name);
+/* -------------------------------------------------------------------------- */
+
+/**
+ * The 'idp_from_Py*' functions expect that the input type has been checked before
+ * and return NULL if the IDProperty can't be created.
+ */
+
+static IDProperty *idp_from_PyFloat(const char *name, PyObject *ob)
+{
+	IDPropertyTemplate val = {0};
+	val.d = PyFloat_AsDouble(ob);
+	return IDP_New(IDP_DOUBLE, &val, name);
+}
+
+static IDProperty *idp_from_PyLong(const char *name, PyObject *ob)
+{
+	IDPropertyTemplate val = {0};
+	val.i = _PyLong_AsInt(ob);
+	if (val.i == -1 && PyErr_Occurred()) {
+		return NULL;
 	}
-	else if (PyUnicode_Check(ob)) {
+	return IDP_New(IDP_INT, &val, name);
+}
+
+static IDProperty *idp_from_PyUnicode(const char *name, PyObject *ob)
+{
+	IDProperty *prop;
+	IDPropertyTemplate val = {0};
 #ifdef USE_STRING_COERCE
-		Py_ssize_t value_size;
-		PyObject *value_coerce = NULL;
-		val.string.str = PyC_UnicodeAsByteAndSize(ob, &value_size, &value_coerce);
-		val.string.len = (int)value_size + 1;
-		val.string.subtype = IDP_STRING_SUB_UTF8;
-		prop = IDP_New(IDP_STRING, &val, name);
-		Py_XDECREF(value_coerce);
+	Py_ssize_t value_size;
+	PyObject *value_coerce = NULL;
+	val.string.str = PyC_UnicodeAsByteAndSize(ob, &value_size, &value_coerce);
+	val.string.len = (int)value_size + 1;
+	val.string.subtype = IDP_STRING_SUB_UTF8;
+	prop = IDP_New(IDP_STRING, &val, name);
+	Py_XDECREF(value_coerce);
 #else
-		val.str = _PyUnicode_AsString(ob);
-		prop = IDP_New(IDP_STRING, val, name);
+	val.str = _PyUnicode_AsString(ob);
+	prop = IDP_New(IDP_STRING, val, name);
 #endif
-	}
-	else if (PyBytes_Check(ob)) {
-		val.string.str = PyBytes_AS_STRING(ob);
-		val.string.len = PyBytes_GET_SIZE(ob);
-		val.string.subtype = IDP_STRING_SUB_BYTE;
+	return prop;
+}
+
+static IDProperty *idp_from_PyBytes(const char *name, PyObject *ob)
+{
+	IDPropertyTemplate val = {0};
+	val.string.str = PyBytes_AS_STRING(ob);
+	val.string.len = PyBytes_GET_SIZE(ob);
+	val.string.subtype = IDP_STRING_SUB_BYTE;
+	return IDP_New(IDP_STRING, &val, name);
+}
 
-		prop = IDP_New(IDP_STRING, &val, name);
-		//prop = IDP_NewString(PyBytes_AS_STRING(ob), name, PyBytes_GET_SIZE(ob));
-		//prop->subtype = IDP_STRING_SUB_BYTE;
+static int idp_array_type_from_format_char(char format)
+{
+	if (format == 'i') return IDP_INT;
+	if (format == 'f') return IDP_FLOAT;
+	if (format == 'd') return IDP_DOUBLE;
+	return -1;
+}
+
+static const char *idp_format_from_array_type(int type)
+{
+	if (type == IDP_INT) return "i";
+	if (type == IDP_FLOAT) return "f";
+	if (type == IDP_DOUBLE) return "d";
+	return NULL;
+}
+
+static IDProperty *idp_from_PySequence_Buffer(const char *name, Py_buffer *buffer)
+{
+	IDProperty *prop;
+	IDPropertyTemplate val = {0};
+
+	int format = idp_array_type_from_format_char(*buffer->format);
+	if (format == -1) {
+		/* should never happen as the type has been checked before */
+		return NULL;
 	}
-	else if (PySequence_Check(ob)) {
-		PyObject *ob_seq_fast;
-		PyObject **ob_seq_fast_items;
-		PyObject *item;
-		int i;
+	else {
+		val.array.type = format;
+		val.array.len = buffer->len / buffer->itemsize;
+	}
+	prop = IDP_New(IDP_ARRAY, &val, name);
+	memcpy(IDP_Array(prop), buffer->buf, buffer->len);
+	return prop;
+}
 
-		if (!(ob_seq_fast = PySequence_Fast(ob, "py -> idprop"))) {
-			return false;
-		}
+static IDProperty *idp_from_PySequence_Fast(const char *name, PyObject *ob)
+{
+	IDProperty *prop;
+	IDPropertyTemplate val = {0};
 
-		ob_seq_fast_items = PySequence_Fast_ITEMS(ob_seq_fast);
+	PyObject **ob_seq_fast_items;
+	PyObject *item;
+	int i;
 
-		if ((val.array.type = idp_sequence_type(ob_seq_fast)) == (char)-1) {
-			Py_DECREF(ob_seq_fast);
-			PyErr_SetString(PyExc_TypeError, "only floats, ints and dicts are allowed in ID property arrays");
-			return false;
-		}
+	ob_seq_fast_items = PySequence_Fast_ITEMS(ob);
 
-		/* validate sequence and derive type.
-		 * we assume IDP_INT unless we hit a float
-		 * number; then we assume it's */
+	if ((val.array.type = idp_sequence_type(ob)) == (char)-1) {
+		PyErr_SetString(PyExc_TypeError, "only floats, ints and dicts are allowed in ID property arrays");
+		return NULL;
+	}
 
-		val.array.len = PySequence_Fast_GET_SIZE(ob_seq_fast);
+	/* validate sequence and derive type.
+	 * we assume IDP_INT unless we hit a float
+	 * number; then we assume it's */
 
-		switch (val.array.type) {
-			case IDP_DOUBLE:
-			{
-				double *prop_data;
-
-				prop = IDP_New(IDP_ARRAY, &val, name);
-				prop_data = IDP_Array(prop);
-				for (i = 0; i < val.array.len; i++) {
-					item = ob_seq_fast_items[i];
-					if (((prop_data[i] = PyFloat_AsDouble(item)) == -1.0) && PyErr_Occurred()) {
-						Py_DECREF(ob_seq_fast);
-						return false;
-					}
+	val.array.len = PySequence_Fast_GET_SIZE(ob);
+
+	switch (val.array.type) {
+		case IDP_DOUBLE:
+		{
+			double *prop_data;
+			prop = IDP_New(IDP_ARRAY, &val, name);
+			prop_data = IDP_Array(prop);
+			for (i = 0; i < val.array.len; i++) {
+				item = ob_seq_fast_items[i];
+				if (((prop_data[i] = PyFloat_AsDouble(item)) == -1.0) && PyErr_Occurred()) {
+					return NULL;
 				}
-				break;
 			}
-			case IDP_INT:
-			{
-				int *prop_data;
-				prop = IDP_New(IDP_ARRAY, &val, name);
-				prop_data = IDP_Array(prop);
-				for (i = 0; i < val.array.len; i++) {
-					item = ob_seq_fast_items[i];
-					if (((prop_data[i] = _PyLong_AsInt(item)) == -1) && PyErr_Occurred()) {
-						Py_DECREF(ob_seq_fast);
-						return false;
-					}
+			break;
+		}
+		case IDP_INT:
+		{
+			int *prop_data;
+			prop = IDP_New(IDP_ARRAY, &val, name);
+			prop_data = IDP_Array(prop);
+			for (i = 0; i < val.array.len; i++) {
+				item = ob_seq_fast_items[i];
+				if (((prop_data[i] = _PyLong_AsInt(item)) == -1) && PyErr_Occurred()) {
+					return NULL;
 				}
-				break;
 			}
-			case IDP_IDPARRAY:
-			{
-				prop = IDP_NewIDPArray(name);
-				for (i = 0; i < val.array.len; i++) {
-					item = ob_seq_fast_items[i];
-
-					if (BPy_IDProperty_Map_ValidateAndCreate(NULL, prop, item) == false) {
-						Py_DECREF(ob_seq_fast);
-						return false;
-					}
+			break;
+		}
+		case IDP_IDPARRAY:
+		{
+			prop = IDP_NewIDPArray(name);
+			for (i = 0; i < val.array.len; i++) {
+				item = ob_seq_fast_items[i];
+				if (BPy_IDProperty_Map_ValidateAndCreate(NULL, prop, item) == false) {
+					return NULL;
 				}
-				break;
 			}
-			default:
-				/* should never happen */
-				Py_DECREF(ob_seq_fast);
-				PyErr_SetString(PyExc_RuntimeError, "internal error with idp array.type");
-				return false;
+			break;
 		}
+		default:
+			/* should never happen */
+			PyErr_SetString(PyExc_RuntimeError, "internal error with idp array.type");
+			return NULL;
+	}
+	return prop;
+}
 
-		Py_DECREF(ob_seq_fast);
+
+static IDProperty *idp_from_PySequence(const char *name, PyObject *ob)
+{
+	Py_buffer buffer;
+	bool use_buffer = false;
+
+	if (PyObject_CheckBuffer(ob)) {
+		PyObject_GetBuffer(ob, &buffer, PyBUF_SIMPLE | PyBUF_FORMAT);
+		char format = *buffer.format;
+		if (ELEM(format, 'i', 'f', 'd')) {
+			use_buffer = true;
+		}
+		else {
+			PyBuffer_Release(&buffer);
+		}
 	}
-	else if (PyMapping_Check(ob)) {
-		PyObject *keys, *vals, *key, *pval;
-		int i, len;
-		/*yay! we get into recursive stuff now!*/
-		keys = PyMapping_Keys(ob);
-		vals = PyMapping_Values(ob);
-
-		/* we allocate the group first; if we hit any invalid data,
-		 * we can delete it easily enough.*/
-		prop = IDP_New(IDP_GROUP, &val, name);
-		len = PyMapping_Length(ob);
-		for (i = 0; i < len; i++) {
-			key = PySequence_GetItem(keys, i);
-			pval = PySequence_GetItem(vals, i);
-			if (BPy_IDProperty_Map_ValidateAndCreate(key, prop, pval) == false) {
-				IDP_FreeProperty(prop);
-				MEM_freeN(prop);
-				Py_XDECREF(keys);
-				Py_XDECREF(vals);
-				Py_XDECREF(key);
-				Py_XDECREF(pval);
-				/* error is already set */
-				return false;
-			}
+
+	if (use_buffer) {
+		IDProperty *prop = idp_from_PySequence_Buffer(name, &buffer);
+		PyBuffer_Release(&buffer);
+		return prop;
+	}
+	else {
+		PyObject *ob_seq_fast = PySequence_Fast(ob, "py -> idprop");
+		if (ob_seq_fast != NULL) {
+			IDProperty *prop = idp_from_PySequence_Fast(name, ob_seq_fast);
+			Py_DECREF(ob_seq_fast);
+			return prop;
+		}
+		else {
+			return NULL;
+		}
+	}
+}
+
+static IDProperty *idp_from_PyMapping(const char *name, PyObject *ob)
+{
+	IDProperty *prop;
+	IDPropertyTemplate val = {0};
+
+	PyObject *keys, *vals, *key, *pval;
+	int i, len;
+	/* yay! we get into recursive stuff now! */
+	keys = PyMapping_Keys(ob);
+	vals = PyMapping_Values(ob);
+
+	/* we allocate the group first; if we hit any invalid data,
+	 * we can delete it easily enough.*/
+	prop = IDP_New(IDP_GROUP, &val, name);
+	len = PyMapping_Length(ob);
+	for (i = 0; i < len; i++) {
+		key = PySequence_GetItem(keys, i);
+		pval = PySequence_GetItem(vals, i);
+		if (BPy_IDProperty_Map_ValidateAndCreate(key, prop, pval) == false) {
+			IDP_FreeProperty(prop);
+			MEM_freeN(prop);
+			Py_XDECREF(keys);
+			Py_XDECREF(vals);
 			Py_XDECREF(key);
 			Py_XDECREF(pval);
+			/* error is already set */
+			return NULL;
 		}
-		Py_XDECREF(keys);
-		Py_XDECREF(vals);
+		Py_XDECREF(key);
+		Py_XDECREF(pval);
+	}
+	Py_XDECREF(keys);
+	Py_XDECREF(vals);
+	return prop;
+}
+
+static IDProperty *idp_from_DatablockPointer(const char *name, PyObject *ob, IDPropertyTemplate *val)
+{
+	pyrna_id_FromPyObject(ob, &val->id);
+	return IDP_New(IDP_ID, val, name);
+}
+
+static IDProperty *idp_from_PyObject(PyObject *name_obj, PyObject *ob)
+{
+	IDPropertyTemplate val = {0};
+	const char *name = idp_try_read_name(name_obj);
+	if (name == NULL) {
+		return NULL;
+	}
+
+	if (PyFloat_Check(ob)) {
+		return idp_from_PyFloat(name, ob);
+	}
+	else if (PyLong_Check(ob)) {
+		return idp_from_PyLong(name, ob);
+	}
+	else if (PyUnicode_Check(ob)) {
+		return idp_from_PyUnicode(name, ob);
+	}
+	else if (PyBytes_Check(ob)) {
+		return idp_from_PyBytes(name, ob);
+	}
+	else if (PySequence_Check(ob)) {
+		return idp_from_PySequence(name, ob);
+	}
+	else if (ob == Py_None || pyrna_id_CheckPyObject(ob)) {
+		return idp_from_DatablockPointer(name, ob, &val);
+	}
+	else if (PyMapping_Check(ob)) {
+		return idp_from_PyMapping(name, ob);
 	}
 	else {
 		PyErr_Format(PyExc_TypeError,
 		             "invalid id-property type %.200s not supported",
 		             Py_TYPE(ob)->tp_name);
+		return NULL;
+	}
+}
+
+/* -------------------------------------------------------------------------- */
+
+/**
+ * \note group can be a pointer array or a group.
+ * assume we already checked key is a string.
+ *
+ * \return success.
+ */
+bool BPy_IDProperty_Map_ValidateAndCreate(PyObject *name_obj, IDProperty *group, PyObject *ob)
+{
+	IDProperty *prop = idp_from_PyObject(name_obj, ob);
+	if (prop == NULL) {
 		return false;
 	}
 
 	if (group->type == IDP_IDPARRAY) {
 		IDP_AppendArray(group, prop);
-		// IDP_FreeProperty(item);  /* IDP_AppendArray does a shallow copy (memcpy), only free memory */
+		/* IDP_AppendArray does a shallow copy (memcpy), only free memory */
 		MEM_freeN(prop);
 	}
 	else {
@@ -613,6 +751,8 @@ static PyObject *BPy_IDGroup_MapDataToPy(IDProperty *prop)
 			return idprop_py_from_idp_float(prop);
 		case IDP_DOUBLE:
 			return idprop_py_from_idp_double(prop);
+		case IDP_ID:
+			return idprop_py_from_idp_id(prop);
 		case IDP_ARRAY:
 		{
 			PyObject *seq = PyList_New(prop->len);
@@ -1371,6 +1511,44 @@ static PyMappingMethods BPy_IDArray_AsMapping = {
 	(objobjargproc)BPy_IDArray_ass_subscript
 };
 
+static int itemsize_by_idarray_type(int array_type)
+{
+	if (array_type == IDP_INT) return sizeof(int);
+	if (array_type == IDP_FLOAT) return sizeof(float);
+	if (array_type == IDP_DOUBLE) return sizeof(double);
+	return -1;  /* should never happen */
+}
+
+static int BPy_IDArray_getbuffer(BPy_IDArray *self, Py_buffer *view, int flags)
+{
+	IDProperty *prop = self->prop;
+	int itemsize = itemsize_by_idarray_type(prop->subtype);
+	int length = itemsize * prop->len;
+
+	if (PyBuffer_FillInfo(view, (PyObject *)self, IDP_Array(prop), length, false, flags) == -1) {
+		return -1;
+	}
+
+	view->itemsize = itemsize;
+	view->format = (char *)idp_format_from_array_type(prop->subtype);
+
+	Py_ssize_t *shape = MEM_mallocN(sizeof(Py_ssize_t), __func__);
+	shape[0] = prop->len;
+	view->shape = shape;
+
+	return 0;
+}
+
+static void BPy_IDArray_releasebuffer(BPy_IDArray *UNUSED(self), Py_buffer *view)
+{
+	MEM_freeN(view->shape);
+}
+
+static PyBufferProcs BPy_IDArray_Buffer = {
+	(getbufferproc)BPy_IDArray_getbuffer,
+	(releasebufferproc)BPy_IDArray_releasebuffer,
+};
+
 
 PyTypeObject BPy_IDArray_Type = {
 	PyVarObject_HEAD_INIT(NULL, 0)
@@ -1403,7 +1581,7 @@ PyTypeObject BPy_IDArray_Type = {
 	NULL,                       /* setattrofunc tp_setattro; */
 
 	/* Functions to access object as input/output buffer */
-	NULL,                       /* PyBufferProcs *tp_as_buffer; */
+	&BPy_IDArray_Buffer,        /* PyBufferProcs *tp_as_buffer; */
 
 	/*** Flags to define presence of optional/expanded features ***/
 	Py_TPFLAGS_DEFAULT,         /* long tp_flags; */
diff --git a/source/blender/python/intern/bpy_props.c b/source/blender/python/intern/bpy_props.c
index e61018865ab..2656e612b18 100644
--- a/source/blender/python/intern/bpy_props.c
+++ b/source/blender/python/intern/bpy_props.c
@@ -50,11 +50,13 @@
 #include "../generic/py_capi_utils.h"
 
 /* initial definition of callback slots we'll probably have more than 1 */
-#define BPY_DATA_CB_SLOT_SIZE 3
-
-#define BPY_DATA_CB_SLOT_UPDATE 0
-#define BPY_DATA_CB_SLOT_GET 1
-#define BPY_DATA_CB_SLOT_SET 2
+enum {
+	BPY_DATA_CB_SLOT_UPDATE     = 0,
+	BPY_DATA_CB_SLOT_GET        = 1,
+	BPY_DATA_CB_SLOT_SET        = 2,
+	BPY_DATA_CB_SLOT_POLL       = 3,
+	BPY_DATA_CB_SLOT_SIZE       = 4,
+};
 
 extern BPy_StructRNA *bpy_context_module;
 
@@ -71,6 +73,9 @@ static EnumPropertyItem property_flag_items[] = {
 "   :arg options: Enumerator in ['HIDDEN', 'SKIP_SAVE', 'ANIMATABLE', 'LIBRARY_EDITABLE', 'PROPORTIONAL'," \
                                 "'TEXTEDIT_UPDATE'].\n" \
 "   :type options: set\n" \
+"   :arg poll: function to be called to determine whether an item is valid for this property.\n" \
+"              The function must take 2 values (self,object) and return Bool.\n" \
+"   :type poll: function\n" \
 
 static EnumPropertyItem property_flag_enum_items[] = {
 	{PROP_HIDDEN, "HIDDEN", 0, "Hidden", ""},
@@ -230,7 +235,7 @@ static PyObject *bpy_prop_deferred_return(PyObject *func, PyObject *kw)
 static void bpy_prop_update_cb(struct bContext *C, struct PointerRNA *ptr, struct PropertyRNA *prop)
 {
 	PyGILState_STATE gilstate;
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -279,7 +284,7 @@ static void bpy_prop_update_cb(struct bContext *C, struct PointerRNA *ptr, struc
 
 static int bpy_prop_boolean_get_cb(struct PointerRNA *ptr, struct PropertyRNA *prop)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -337,7 +342,7 @@ static int bpy_prop_boolean_get_cb(struct PointerRNA *ptr, struct PropertyRNA *p
 
 static void bpy_prop_boolean_set_cb(struct PointerRNA *ptr, struct PropertyRNA *prop, int value)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -389,9 +394,54 @@ static void bpy_prop_boolean_set_cb(struct PointerRNA *ptr, struct PropertyRNA *
 	}
 }
 
+static int bpy_prop_poll_cb(struct PointerRNA *self, PointerRNA candidate, struct PropertyRNA *prop)
+{
+	PyObject *py_self;
+	PyObject *py_candidate;
+	PyObject *py_func;
+	PyObject **py_data = RNA_property_py_data_get(prop);
+	PyObject *args;
+	PyObject *ret;
+	bool result;
+	const int is_write_ok = pyrna_write_check();
+	PyGILState_STATE gilstate = PyGILState_Ensure();
+
+	BLI_assert(self != NULL);
+
+	py_self = pyrna_struct_as_instance(self);
+	py_candidate = pyrna_struct_as_instance(&candidate);
+	py_func = py_data[BPY_DATA_CB_SLOT_POLL];
+
+	if (!is_write_ok)
+		pyrna_write_set(true);
+
+	args = PyTuple_New(2);
+	PyTuple_SET_ITEM(args, 0, py_self);
+	PyTuple_SET_ITEM(args, 1, py_candidate);
+
+	ret = PyObject_CallObject(py_func, args);
+
+	Py_DECREF(args);
+
+	if (ret == NULL) {
+		printf_func_error(py_func);
+		result = false;
+	}
+	else {
+		result = PyObject_IsTrue(ret);
+		Py_DECREF(ret);
+	}
+
+	PyGILState_Release(gilstate);
+	if (!is_write_ok)
+		pyrna_write_set(false);
+
+	return result;
+}
+
 static void bpy_prop_boolean_array_get_cb(struct PointerRNA *ptr, struct PropertyRNA *prop, int *values)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -452,7 +502,7 @@ static void bpy_prop_boolean_array_get_cb(struct PointerRNA *ptr, struct Propert
 
 static void bpy_prop_boolean_array_set_cb(struct PointerRNA *ptr, struct PropertyRNA *prop, const int *values)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -513,7 +563,7 @@ static void bpy_prop_boolean_array_set_cb(struct PointerRNA *ptr, struct Propert
 
 static int bpy_prop_int_get_cb(struct PointerRNA *ptr, struct PropertyRNA *prop)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -571,7 +621,7 @@ static int bpy_prop_int_get_cb(struct PointerRNA *ptr, struct PropertyRNA *prop)
 
 static void bpy_prop_int_set_cb(struct PointerRNA *ptr, struct PropertyRNA *prop, int value)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -625,7 +675,7 @@ static void bpy_prop_int_set_cb(struct PointerRNA *ptr, struct PropertyRNA *prop
 
 static void bpy_prop_int_array_get_cb(struct PointerRNA *ptr, struct PropertyRNA *prop, int *values)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -686,7 +736,7 @@ static void bpy_prop_int_array_get_cb(struct PointerRNA *ptr, struct PropertyRNA
 
 static void bpy_prop_int_array_set_cb(struct PointerRNA *ptr, struct PropertyRNA *prop, const int *values)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -747,7 +797,7 @@ static void bpy_prop_int_array_set_cb(struct PointerRNA *ptr, struct PropertyRNA
 
 static float bpy_prop_float_get_cb(struct PointerRNA *ptr, struct PropertyRNA *prop)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -805,7 +855,7 @@ static float bpy_prop_float_get_cb(struct PointerRNA *ptr, struct PropertyRNA *p
 
 static void bpy_prop_float_set_cb(struct PointerRNA *ptr, struct PropertyRNA *prop, float value)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -859,7 +909,7 @@ static void bpy_prop_float_set_cb(struct PointerRNA *ptr, struct PropertyRNA *pr
 
 static void bpy_prop_float_array_get_cb(struct PointerRNA *ptr, struct PropertyRNA *prop, float *values)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -920,7 +970,7 @@ static void bpy_prop_float_array_get_cb(struct PointerRNA *ptr, struct PropertyR
 
 static void bpy_prop_float_array_set_cb(struct PointerRNA *ptr, struct PropertyRNA *prop, const float *values)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -981,7 +1031,7 @@ static void bpy_prop_float_array_set_cb(struct PointerRNA *ptr, struct PropertyR
 
 static void bpy_prop_string_get_cb(struct PointerRNA *ptr, struct PropertyRNA *prop, char *value)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -1040,7 +1090,7 @@ static void bpy_prop_string_get_cb(struct PointerRNA *ptr, struct PropertyRNA *p
 
 static int bpy_prop_string_length_cb(struct PointerRNA *ptr, struct PropertyRNA *prop)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -1102,7 +1152,7 @@ static int bpy_prop_string_length_cb(struct PointerRNA *ptr, struct PropertyRNA
 
 static void bpy_prop_string_set_cb(struct PointerRNA *ptr, struct PropertyRNA *prop, const char *value)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -1163,7 +1213,7 @@ static void bpy_prop_string_set_cb(struct PointerRNA *ptr, struct PropertyRNA *p
 
 static int bpy_prop_enum_get_cb(struct PointerRNA *ptr, struct PropertyRNA *prop)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -1221,7 +1271,7 @@ static int bpy_prop_enum_get_cb(struct PointerRNA *ptr, struct PropertyRNA *prop
 
 static void bpy_prop_enum_set_cb(struct PointerRNA *ptr, struct PropertyRNA *prop, int value)
 {
-	PyObject **py_data = (PyObject **)RNA_property_py_data_get(prop);
+	PyObject **py_data = RNA_property_py_data_get(prop);
 	PyObject *py_func;
 	PyObject *args;
 	PyObject *self;
@@ -1598,6 +1648,16 @@ static void bpy_prop_callback_assign_update(struct PropertyRNA *prop, PyObject *
 	}
 }
 
+static void bpy_prop_callback_assign_pointer(struct PropertyRNA *prop, PyObject *poll_cb)
+{
+	if (poll_cb && poll_cb != Py_None) {
+		PyObject **py_data = bpy_prop_py_data_get(prop);
+
+		RNA_def_property_poll_runtime(prop, (void *) bpy_prop_poll_cb);
+		py_data[BPY_DATA_CB_SLOT_POLL] = poll_cb;
+	}
+}
+
 static void bpy_prop_callback_assign_boolean(struct PropertyRNA *prop, PyObject *get_cb, PyObject *set_cb)
 {
 	BooleanPropertyGetFunc rna_get_cb = NULL;
@@ -1904,7 +1964,7 @@ static void bpy_prop_callback_assign_enum(struct PropertyRNA *prop, PyObject *ge
 "   :type set: function\n" \
 
 #define BPY_PROPDEF_TYPE_DOC \
-"   :arg type: A subclass of :class:`bpy.types.PropertyGroup`.\n" \
+"   :arg type: A subclass of :class:`bpy.types.PropertyGroup` or :class:`bpy.types.ID`.\n" \
 "   :type type: class\n" \
 
 #if 0
@@ -2772,7 +2832,7 @@ static PyObject *BPy_EnumProperty(PyObject *self, PyObject *args, PyObject *kw)
 	Py_RETURN_NONE;
 }
 
-static StructRNA *pointer_type_from_py(PyObject *value, const char *error_prefix)
+StructRNA *pointer_type_from_py(PyObject *value, const char *error_prefix)
 {
 	StructRNA *srna;
 
@@ -2782,25 +2842,18 @@ static StructRNA *pointer_type_from_py(PyObject *value, const char *error_prefix
 			PyObject *msg = PyC_ExceptionBuffer();
 			const char *msg_char = _PyUnicode_AsString(msg);
 			PyErr_Format(PyExc_TypeError,
-			             "%.200s expected an RNA type derived from PropertyGroup, failed with: %s",
+			             "%.200s expected an RNA type, failed with: %s",
 			             error_prefix, msg_char);
 			Py_DECREF(msg);
 		}
 		else {
 			PyErr_Format(PyExc_TypeError,
-			             "%.200s expected an RNA type derived from PropertyGroup, failed with type '%s'",
+			             "%.200s expected an RNA type, failed with type '%s'",
 			             error_prefix, Py_TYPE(value)->tp_name);
 		}
 		return NULL;
 	}
 
-	if (!RNA_struct_is_a(srna, &RNA_PropertyGroup)) {
-		PyErr_Format(PyExc_TypeError,
-		             "%.200s expected an RNA type derived from PropertyGroup",
-		             error_prefix);
-		return NULL;
-	}
-
 	return srna;
 }
 
@@ -2809,7 +2862,8 @@ PyDoc_STRVAR(BPy_PointerProperty_doc,
                               "name=\"\", "
                               "description=\"\", "
                               "options={'ANIMATABLE'}, "
-                              "update=None)\n"
+                              "update=None,\n"
+                              "poll=None)\n"
 "\n"
 "   Returns a new pointer property definition.\n"
 "\n"
@@ -2819,14 +2873,14 @@ BPY_PROPDEF_DESC_DOC
 BPY_PROPDEF_OPTIONS_DOC
 BPY_PROPDEF_UPDATE_DOC
 );
-static PyObject *BPy_PointerProperty(PyObject *self, PyObject *args, PyObject *kw)
+PyObject *BPy_PointerProperty(PyObject *self, PyObject *args, PyObject *kw)
 {
 	StructRNA *srna;
 
 	BPY_PROPDEF_HEAD(PointerProperty);
 
 	if (srna) {
-		static const char *kwlist[] = {"attr", "type", "name", "description", "options", "update", NULL};
+		static const char *kwlist[] = {"attr", "type", "name", "description", "options", "poll", "update", NULL};
 		const char *id = NULL, *name = NULL, *description = "";
 		int id_len;
 		PropertyRNA *prop;
@@ -2834,33 +2888,47 @@ static PyObject *BPy_PointerProperty(PyObject *self, PyObject *args, PyObject *k
 		PyObject *type = Py_None;
 		PyObject *pyopts = NULL;
 		int opts = 0;
-		PyObject *update_cb = NULL;
+		PyObject *update_cb = NULL, *poll_cb = NULL;
 
 		if (!PyArg_ParseTupleAndKeywords(args, kw,
-		                                 "s#O|ssO!O:PointerProperty",
+		                                 "s#O|ssO!OOO:PointerProperty",
 		                                 (char **)kwlist, &id, &id_len,
 		                                 &type, &name, &description,
 		                                 &PySet_Type, &pyopts,
-		                                 &update_cb))
+		                                 &poll_cb, &update_cb))
 		{
 			return NULL;
 		}
 
 		BPY_PROPDEF_CHECK(PointerProperty, property_flag_items);
 
-		ptype = pointer_type_from_py(type, "PointerProperty(...):");
+		ptype = pointer_type_from_py(type, "PointerProperty(...)");
 		if (!ptype)
 			return NULL;
-
+		if (!RNA_struct_is_a(ptype, &RNA_PropertyGroup) && !RNA_struct_is_ID(ptype)) {
+			PyErr_Format(PyExc_TypeError,
+			             "PointerProperty(...) expected an RNA type derived from %.200s or %.200s",
+			             RNA_struct_ui_name(&RNA_ID), RNA_struct_ui_name(&RNA_PropertyGroup));
+			return NULL;
+		}
 		if (bpy_prop_callback_check(update_cb, "update", 2) == -1) {
 			return NULL;
 		}
-
+		if (bpy_prop_callback_check(poll_cb, "poll", 2) == -1) {
+			return NULL;
+		}
 		prop = RNA_def_pointer_runtime(srna, id, ptype, name ? name : id, description);
 		if (pyopts) {
 			bpy_prop_assign_flag(prop, opts);
 		}
+
+		if (RNA_struct_idprops_contains_datablock(ptype)) {
+			if (RNA_struct_is_a(srna, &RNA_PropertyGroup)) {
+				RNA_def_struct_flag(srna, STRUCT_CONTAINS_DATABLOCK_IDPROPERTIES);
+			}
+		}
 		bpy_prop_callback_assign_update(prop, update_cb);
+		bpy_prop_callback_assign_pointer(prop, poll_cb);
 		RNA_def_property_duplicate_pointers(srna, prop);
 	}
 	Py_RETURN_NONE;
@@ -2879,7 +2947,7 @@ BPY_PROPDEF_NAME_DOC
 BPY_PROPDEF_DESC_DOC
 BPY_PROPDEF_OPTIONS_DOC
 );
-static PyObject *BPy_CollectionProperty(PyObject *self, PyObject *args, PyObject *kw)
+PyObject *BPy_CollectionProperty(PyObject *self, PyObject *args, PyObject *kw)
 {
 	StructRNA *srna;
 
@@ -2910,10 +2978,23 @@ static PyObject *BPy_CollectionProperty(PyObject *self, PyObject *args, PyObject
 		if (!ptype)
 			return NULL;
 
+		if (!RNA_struct_is_a(ptype, &RNA_PropertyGroup)) {
+			PyErr_Format(PyExc_TypeError,
+				"CollectionProperty(...) expected an RNA type derived from %.200s",
+				RNA_struct_ui_name(&RNA_ID), RNA_struct_ui_name(&RNA_PropertyGroup));
+			return NULL;
+		}
+
 		prop = RNA_def_collection_runtime(srna, id, ptype, name ? name : id, description);
 		if (pyopts) {
 			bpy_prop_assign_flag(prop, opts);
 		}
+
+		if (RNA_struct_idprops_contains_datablock(ptype)) {
+			if (RNA_struct_is_a(srna, &RNA_PropertyGroup)) {
+				RNA_def_struct_flag(srna, STRUCT_CONTAINS_DATABLOCK_IDPROPERTIES);
+			}
+		}
 		RNA_def_property_duplicate_pointers(srna, prop);
 	}
 	Py_RETURN_NONE;
diff --git a/source/blender/python/intern/bpy_props.h b/source/blender/python/intern/bpy_props.h
index c9934ca0cf3..614c1b4b708 100644
--- a/source/blender/python/intern/bpy_props.h
+++ b/source/blender/python/intern/bpy_props.h
@@ -30,6 +30,10 @@
 
 PyObject *BPY_rna_props(void);
 
+PyObject *BPy_PointerProperty(PyObject *self, PyObject *args, PyObject *kw);
+PyObject *BPy_CollectionProperty(PyObject *self, PyObject *args, PyObject *kw);
+StructRNA *pointer_type_from_py(PyObject *value, const char *error_prefix);
+
 #define PYRNA_STACK_ARRAY 32
 
 #endif
diff --git a/source/blender/python/intern/bpy_rna.c b/source/blender/python/intern/bpy_rna.c
index 2fd46ab94f0..00627030db3 100644
--- a/source/blender/python/intern/bpy_rna.c
+++ b/source/blender/python/intern/bpy_rna.c
@@ -1934,16 +1934,10 @@ static int pyrna_py_to_prop(
 					}
 					else {
 						/* data == NULL, assign to RNA */
-						if (value == Py_None) {
-							PointerRNA valueptr = {{NULL}};
-							RNA_property_pointer_set(ptr, prop, valueptr);
-						}
-						else if (RNA_struct_is_a(param->ptr.type, ptr_type)) {
-							RNA_property_pointer_set(ptr, prop, param->ptr);
-						}
-						else {
+						if (value == Py_None || RNA_struct_is_a(param->ptr.type, ptr_type))
+							RNA_property_pointer_set(ptr, prop, value == Py_None ? PointerRNA_NULL : param->ptr);
+						else
 							raise_error = true;
-						}
 					}
 
 					if (raise_error) {
@@ -3277,6 +3271,16 @@ static int pyrna_struct_ass_subscript(BPy_StructRNA *self, PyObject *key, PyObje
 		return -1;
 	}
 
+	BPy_StructRNA *val = (BPy_StructRNA *)value;
+	if (val && self->ptr.type && val->ptr.type) {
+		if (!RNA_struct_idprops_datablock_allowed(self->ptr.type) &&
+		    RNA_struct_idprops_contains_datablock(val->ptr.type))
+		{
+			PyErr_SetString(PyExc_TypeError, "bpy_struct[key] = val: datablock id properties not supported for this type");
+			return -1;
+		}
+	}
+
 	return BPy_Wrap_SetMapItem(group, key, value);
 }
 
@@ -6745,7 +6749,7 @@ PyObject *pyrna_id_CreatePyObject(ID *id)
 
 bool pyrna_id_FromPyObject(PyObject *obj, ID **id)
 {
-	if (BPy_StructRNA_Check(obj) && (RNA_struct_is_ID(((BPy_StructRNA *)obj)->ptr.type))) {
+	if (pyrna_id_CheckPyObject(obj)) {
 		*id = ((BPy_StructRNA *)obj)->ptr.id.data;
 		return true;
 	}
@@ -6755,6 +6759,11 @@ bool pyrna_id_FromPyObject(PyObject *obj, ID **id)
 	}
 }
 
+bool pyrna_id_CheckPyObject(PyObject *obj)
+{
+	return BPy_StructRNA_Check(obj) && (RNA_struct_is_ID(((BPy_StructRNA *) obj)->ptr.type));
+}
+
 void BPY_rna_init(void)
 {
 #ifdef USE_MATHUTILS  /* register mathutils callbacks, ok to run more than once. */
@@ -7089,6 +7098,21 @@ static int deferred_register_prop(StructRNA *srna, PyObject *key, PyObject *item
 			args_fake = PyTuple_New(1);
 			PyTuple_SET_ITEM(args_fake, 0, py_srna_cobject);
 
+			PyObject *type = PyDict_GetItemString(py_kw, "type");
+			StructRNA *type_srna = srna_from_self(type, "");
+			if (type_srna) {
+				if (!RNA_struct_idprops_datablock_allowed(srna) &&
+				    (*(PyCFunctionWithKeywords)PyCFunction_GET_FUNCTION(py_func) == BPy_PointerProperty ||
+				     *(PyCFunctionWithKeywords)PyCFunction_GET_FUNCTION(py_func) == BPy_CollectionProperty) &&
+				    RNA_struct_idprops_contains_datablock(type_srna))
+				{
+					PyErr_Format(PyExc_ValueError,
+								 "bpy_struct \"%.200s\" doesn't support datablock properties \n",
+								 RNA_struct_identifier(srna));
+					return -1;
+				}
+			}
+
 			py_ret = PyObject_Call(py_func, args_fake, py_kw);
 
 			if (py_ret) {
diff --git a/source/blender/python/intern/bpy_rna.h b/source/blender/python/intern/bpy_rna.h
index e38d4f095d6..605f79b1ad8 100644
--- a/source/blender/python/intern/bpy_rna.h
+++ b/source/blender/python/intern/bpy_rna.h
@@ -179,6 +179,7 @@ PyObject *pyrna_prop_CreatePyObject(PointerRNA *ptr, PropertyRNA *prop);
 /* extern'd by other modules which don't deal closely with RNA */
 PyObject *pyrna_id_CreatePyObject(struct ID *id);
 bool      pyrna_id_FromPyObject(PyObject *obj, struct ID **id);
+bool      pyrna_id_CheckPyObject(PyObject *obj);
 
 /* operators also need this to set args */
 int pyrna_pydict_to_props(PointerRNA *ptr, PyObject *kw, const bool all_args, const char *error_prefix);
diff --git a/source/blender/python/mathutils/mathutils_Matrix.c b/source/blender/python/mathutils/mathutils_Matrix.c
index 4e980e4c0e6..bd44e77e7c6 100644
--- a/source/blender/python/mathutils/mathutils_Matrix.c
+++ b/source/blender/python/mathutils/mathutils_Matrix.c
@@ -1301,7 +1301,7 @@ PyDoc_STRVAR(Matrix_to_scale_doc,
 "   :return: Return the scale of a matrix.\n"
 "   :rtype: :class:`Vector`\n"
 "\n"
-"   .. note:: This method does not return negative a scale on any axis because it is not possible to obtain this data from the matrix alone.\n"
+"   .. note:: This method does not return a negative scale on any axis because it is not possible to obtain this data from the matrix alone.\n"
 );
 static PyObject *Matrix_to_scale(MatrixObject *self)
 {
@@ -1390,11 +1390,11 @@ PyDoc_STRVAR(Matrix_invert_doc,
 "\n"
 "   Set the matrix to its inverse.\n"
 "\n"
-"   :arg fallback: Set the matrix to this value when the inverse can't be calculated\n"
+"   :arg fallback: Set the matrix to this value when the inverse cannot be calculated\n"
 "      (instead of raising a :exc:`ValueError` exception).\n"
 "   :type fallback: :class:`Matrix`\n"
 "\n"
-"   .. seealso:: <https://en.wikipedia.org/wiki/Inverse_matrix>\n"
+"   .. seealso:: `Inverse matrix <https://en.wikipedia.org/wiki/Inverse_matrix>` on Wikipedia.\n"
 );
 static PyObject *Matrix_invert(MatrixObject *self, PyObject *args)
 {
@@ -1505,7 +1505,7 @@ PyDoc_STRVAR(Matrix_invert_safe_doc,
 "   If degenerated (e.g. zero scale on an axis), add some epsilon to its diagonal, to get an invertible one.\n"
 "   If tweaked matrix is still degenerated, set to the identity matrix instead.\n"
 "\n"
-"   .. seealso:: <https://en.wikipedia.org/wiki/Inverse_matrix>\n"
+"   .. seealso:: `Inverse Matrix <https://en.wikipedia.org/wiki/Inverse_matrix>` on Wikipedia.\n"
 );
 static PyObject *Matrix_invert_safe(MatrixObject *self)
 {
@@ -1554,9 +1554,9 @@ PyDoc_STRVAR(Matrix_adjugate_doc,
 "\n"
 "   Set the matrix to its adjugate.\n"
 "\n"
-"   .. note:: When the matrix cant be adjugated a :exc:`ValueError` exception is raised.\n"
+"   .. note:: When the matrix cannot be adjugated a :exc:`ValueError` exception is raised.\n"
 "\n"
-"   .. seealso:: <https://en.wikipedia.org/wiki/Adjugate_matrix>\n"
+"   .. seealso:: `Adjugate matrix <https://en.wikipedia.org/wiki/Adjugate_matrix>` on Wikipedia.\n"
 );
 static PyObject *Matrix_adjugate(MatrixObject *self)
 {
@@ -1733,7 +1733,7 @@ PyDoc_STRVAR(Matrix_determinant_doc,
 "   :return: Return the determinant of a matrix.\n"
 "   :rtype: float\n"
 "\n"
-"   .. seealso:: <https://en.wikipedia.org/wiki/Determinant>\n"
+"   .. seealso:: `Determinant <https://en.wikipedia.org/wiki/Determinant>` on Wikipedia.\n"
 );
 static PyObject *Matrix_determinant(MatrixObject *self)
 {
@@ -1755,7 +1755,7 @@ PyDoc_STRVAR(Matrix_transpose_doc,
 "\n"
 "   Set the matrix to its transpose.\n"
 "\n"
-"   .. seealso:: <https://en.wikipedia.org/wiki/Transpose>\n"
+"   .. seealso:: `Transpose <https://en.wikipedia.org/wiki/Transpose>` on Wikipedia.\n"
 );
 static PyObject *Matrix_transpose(MatrixObject *self)
 {
@@ -1887,10 +1887,10 @@ PyDoc_STRVAR(Matrix_identity_doc,
 "\n"
 "   Set the matrix to the identity matrix.\n"
 "\n"
-"   .. note:: An object with zero location and rotation, a scale of one,\n"
+"   .. note:: An object with a location and rotation of zero, and a scale of one\n"
 "      will have an identity matrix.\n"
 "\n"
-"   .. seealso:: <https://en.wikipedia.org/wiki/Identity_matrix>\n"
+"   .. seealso:: `Identity matrix <https://en.wikipedia.org/wiki/Identity_matrix>` on Wikipedia.\n"
 );
 static PyObject *Matrix_identity(MatrixObject *self)
 {