MBS-10572: Do not remove personas in case of context data deletion

Author: PhMemmel

classes/privacy/provider.php

@@ -295,8 +295,8 @@ public static function delete_data_for_users(approved_userlist $userlist): void
             foreach ($userpersonas as $persona) {
                 // Delete all selections of this persona first.
                 $DB->delete_records('block_ai_chat_personas_selected', ['personasid' => $persona->id]);
-                // Then delete the persona itself.
-                $DB->delete_records('block_ai_chat_personas', ['id' => $persona->id]);
+                // Associated persona records must not be deleted, because they belong to the user and not the aichat instance
+                // context. They could even still be used by different aichat instances.
             }
         }
     }
@@ -330,10 +330,10 @@ public static function delete_data_for_all_users_in_context(\context $context):
         $selections = $DB->get_records('block_ai_chat_personas_selected', ['contextid' => $context->id]);
 
         foreach ($selections as $selection) {
-            // Delete the persona.
-            $DB->delete_records('block_ai_chat_personas', ['id' => $selection->personasid]);
             // Delete the selection.
             $DB->delete_records('block_ai_chat_personas_selected', ['id' => $selection->id]);
+            // Associated persona records must not be deleted, because they belong to the user and not the aichat instance
+            // context. They could even still be used by different aichat instances.
         }
     }
 

tests/privacy/provider_test.php

@@ -413,9 +413,11 @@ public function test_delete_data_for_all_users_in_context(): void {
         $this->assertEquals(data_wiper::ANONYMIZE_STRING, $dbrecord2->prompttext);
         $this->assertEquals(data_wiper::ANONYMIZE_STRING, $dbrecord2->promptcompletion);
 
-        // Verify persona1 and its selection in the deleted context are gone.
-        $this->assertFalse($DB->record_exists('block_ai_chat_personas', ['id' => $persona1id]));
+        // Verify the selection of persona1 in the deleted context is gone.
         $this->assertFalse($DB->record_exists('block_ai_chat_personas_selected', ['id' => $selection1id]));
+        // Verify the persona still exists, because it is not data in this context but belongs to the user and could still
+        // be used in different contexts.
+        $this->assertTrue($DB->record_exists('block_ai_chat_personas', ['id' => $persona1id]));
 
         // Verify persona2 and its selection in other context are still there.
         $this->assertTrue($DB->record_exists('block_ai_chat_personas', ['id' => $persona2id]));
@@ -530,12 +532,14 @@ public function test_delete_data_for_users(): void {
         $this->assertEquals('User 3 prompt', $dbrecord3->prompttext);
         $this->assertEquals('User 3 completion', $dbrecord3->promptcompletion);
 
-        // Verify user1's persona and its selection are deleted.
-        $this->assertFalse($DB->record_exists('block_ai_chat_personas', ['id' => $persona1id]));
+        // Verify the selection of user1's persona is deleted.
         $this->assertFalse($DB->record_exists('block_ai_chat_personas_selected', ['id' => $selection1id]));
+        // Verify the persona still exists, because it is not data in this context but belongs to the user and could still
+        // be used in different contexts.
+        $this->assertTrue($DB->record_exists('block_ai_chat_personas', ['id' => $persona1id]));
 
-        // Verify user2's persona is deleted.
-        $this->assertFalse($DB->record_exists('block_ai_chat_personas', ['id' => $persona2id]));
+        // Verify user2's persona also still exists.
+        $this->assertTrue($DB->record_exists('block_ai_chat_personas', ['id' => $persona2id]));
 
         // Verify user3's persona is not affected.
         $this->assertTrue($DB->record_exists('block_ai_chat_personas', ['id' => $persona3id]));