Tests: Add simple script accessing (almost) all RNA properties.

Only runs on factory startup file, so not all possible paths are
covered. But should reduce likeliness of issues like #133551 in the
future.

tests/python/CMakeLists.txt

@@ -257,6 +257,11 @@ add_blender_test(
   --python ${CMAKE_CURRENT_LIST_DIR}/bl_rna_paths.py
 )
 
+add_blender_test(
+  bl_rna_accessors
+  --python ${CMAKE_CURRENT_LIST_DIR}/bl_rna_accessors.py
+)
+
 # ------------------------------------------------------------------------------
 # BLEND IO & LINKING
 

tests/python/bl_rna_accessors.py

@@ -0,0 +1,82 @@
+# SPDX-FileCopyrightText: 2025 Blender Authors
+#
+# SPDX-License-Identifier: Apache-2.0
+
+
+"""
+Simple test looping over (most of) all RNA API and checking that data can be accessed.
+
+Note that not all RNA is covered, this focuses mainly on data accessible from `bpy.data`.
+"""
+
+import bpy
+import unittest
+
+
+# Walk over all exposed RNA properties in factory startup file, and access them.
+class TestRnaProperties(unittest.TestCase):
+    def process_rna_struct(self, struct, rna_path):
+        # These paths are problematic to process, skip for the time being.
+        SKIP_PROPERTIES = {
+            bpy.types.Depsgraph.bl_rna.properties["object_instances"],
+            # XXX To be removed once #133551 is fixed.
+            bpy.types.ToolSettings.bl_rna.properties["uv_sculpt"],
+        }
+
+        if repr(struct) in self.processed_data:
+            return
+        self.processed_data.add(repr(struct))
+
+        def generate_rna_path(struct, rna_path_root, p, p_data, p_keys_str=[]):
+            if not p_data:
+                return None
+            rna_path_references = [rna_path_root + "." + p.identifier if rna_path_root else p.identifier]
+            if p_keys_str:
+                rna_path_reference = rna_path_references[0]
+                rna_path_references = [rna_path_reference + '[' + p_key + ']' for p_key in p_keys_str if p_key]
+            return rna_path_references[0]
+
+        def process_pointer_property(self, struct, rna_path, p, p_data, p_keys_str=[]):
+            rna_path_sub = generate_rna_path(struct, rna_path, p, p_data, p_keys_str)
+            if p.identifier in {"bl_rna", "rna_type"}:
+                return
+            if isinstance(p_data, bpy.types.ID) and not p_data.is_embedded_data:
+                return
+            if rna_path_sub is None:
+                return
+            self.process_rna_struct(p_data, rna_path_sub)
+
+        for p in struct.bl_rna.properties:
+            if p in SKIP_PROPERTIES:
+                continue
+            if p.type == 'COLLECTION':
+                try:
+                    iter_data = getattr(struct, p.identifier)
+                except:
+                    self.assertTrue(False, msg=f"Failed to retrieve {rna_path}.{p.identifier} collection")
+                for p_idx, (p_key, p_data) in enumerate(iter_data.items()):
+                    p_keys_str = ['"' + p_key + '"', str(p_idx)] if isinstance(p_key, str) else [str(p_key), str(p_idx)]
+                    process_pointer_property(self, struct, rna_path, p, p_data, p_keys_str)
+            elif p.type == 'POINTER':
+                try:
+                    p_data = getattr(struct, p.identifier)
+                except:
+                    self.assertTrue(False, msg=f"Failed to retrieve {rna_path}.{p.identifier} pointer")
+                process_pointer_property(self, struct, rna_path, p, p_data)
+            else:
+                try:
+                    p_data = getattr(struct, p.identifier)
+                except:
+                    self.assertTrue(False, msg=f"Failed to retrieve {rna_path}.{p.identifier} value")
+
+    def test_paths_generation(self):
+        bpy.ops.wm.read_factory_settings()
+        self.processed_data = set()
+        for data_block in bpy.data.user_map().keys():
+            self.process_rna_struct(data_block, "")
+
+
+if __name__ == '__main__':
+    import sys
+    sys.argv = [__file__] + (sys.argv[sys.argv.index("--") + 1:] if "--" in sys.argv else [])
+    unittest.main()