From 3115db58363659dccc6e68830280f5a1563a598c Mon Sep 17 00:00:00 2001
From: 0x29a <demid@opencraft.com>
Date: Tue, 13 Dec 2022 09:22:53 +0100
Subject: [PATCH] feat: implement falling back to HiddenBlock

---
 xmodule/modulestore/mongo/base.py        | 11 ++++++++++-
 xmodule/modulestore/split_mongo/split.py | 11 ++++++++++-
 xmodule/modulestore/xml.py               | 11 ++++++++++-
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/xmodule/modulestore/mongo/base.py b/xmodule/modulestore/mongo/base.py
index 6e9f4c19fd..5f9abf6f93 100644
--- a/xmodule/modulestore/mongo/base.py
+++ b/xmodule/modulestore/mongo/base.py
@@ -521,7 +521,16 @@ class MongoModuleStore(ModuleStoreDraftAndPublished, ModuleStoreWriteBase, Mongo
 
         if default_class is not None:
             module_path, _, class_name = default_class.rpartition('.')
-            class_ = getattr(import_module(module_path), class_name)
+            try:
+                class_ = getattr(import_module(module_path), class_name)
+            except ImportError:
+                fallback_module_path = "xmodule.hidden_block"
+                fallback_class_name = "HiddenDescriptor"
+                log.exception(
+                    "Failed to import the default store class. "
+                    f"Falling back to {fallback_module_path}.{fallback_class_name}"
+                )
+                class_ = getattr(import_module(fallback_module_path), fallback_class_name)
             self.default_class = class_
         else:
             self.default_class = None
diff --git a/xmodule/modulestore/split_mongo/split.py b/xmodule/modulestore/split_mongo/split.py
index 58e6af9816..159642c136 100644
--- a/xmodule/modulestore/split_mongo/split.py
+++ b/xmodule/modulestore/split_mongo/split.py
@@ -656,7 +656,16 @@ class SplitMongoModuleStore(SplitBulkWriteMixin, ModuleStoreWriteBase):
 
         if default_class is not None:
             module_path, __, class_name = default_class.rpartition('.')
-            class_ = getattr(import_module(module_path), class_name)
+            try:
+                class_ = getattr(import_module(module_path), class_name)
+            except ImportError:
+                fallback_module_path = "xmodule.hidden_block"
+                fallback_class_name = "HiddenDescriptor"
+                log.exception(
+                    "Failed to import the default store class. "
+                    f"Falling back to {fallback_module_path}.{fallback_class_name}"
+                )
+                class_ = getattr(import_module(fallback_module_path), fallback_class_name)
             self.default_class = class_
         else:
             self.default_class = None
diff --git a/xmodule/modulestore/xml.py b/xmodule/modulestore/xml.py
index 4213ae6eec..b965872b4f 100644
--- a/xmodule/modulestore/xml.py
+++ b/xmodule/modulestore/xml.py
@@ -335,7 +335,16 @@ class XMLModuleStore(ModuleStoreReadBase):
             self.default_class = None
         else:
             module_path, _, class_name = default_class.rpartition('.')
-            class_ = getattr(import_module(module_path), class_name)
+            try:
+                class_ = getattr(import_module(module_path), class_name)
+            except ImportError:
+                fallback_module_path = "xmodule.hidden_block"
+                fallback_class_name = "HiddenDescriptor"
+                log.exception(
+                    "Failed to import the default store class. "
+                    f"Falling back to {fallback_module_path}.{fallback_class_name}"
+                )
+                class_ = getattr(import_module(fallback_module_path), fallback_class_name)
             self.default_class = class_
 
         # All field data will be stored in an inheriting field data.