fix(migration)_: fix the pinned_messages migration when a message is …

…deleted

Turns out if you had old pinned messages that were still associated with deleted user messages, then the original migration didn't work.
This fixes it.

If someone already ran the migration successfully because they didn't have deleted pinned messages, then it just won't run again and everything is already fine.
If someone was blocked because of the migration, then it will just run fine now.

protocol/migrations/sqlite/1733428521_pinned_messages_add_on_delete_clause.up.sql

@@ -1,3 +1,13 @@
+-- Delete pinned messages that are not associated with any user message
+-- This makes sure the migration below works even if a message is deleted
+DELETE FROM pin_messages
+WHERE NOT EXISTS (
+    SELECT 1
+    FROM user_messages
+    WHERE user_messages.id = pin_messages.message_id
+);
+
+-- Add the ON DELETE CASCADE clause to the foreign key constraint
 CREATE TABLE pin_messages_new (
   id VARCHAR PRIMARY KEY NOT NULL,
   message_id VARCHAR NOT NULL,
@@ -10,10 +20,12 @@ CREATE TABLE pin_messages_new (
   FOREIGN KEY (message_id) REFERENCES user_messages(id) ON DELETE CASCADE
 );
 
+-- Copy the data from the old table to the new table
 INSERT INTO pin_messages_new (id, message_id, whisper_timestamp, chat_id, local_chat_id, clock_value, pinned, pinned_by)
 SELECT id, message_id, whisper_timestamp, chat_id, local_chat_id, clock_value, pinned, pinned_by
 FROM pin_messages;
 
+-- Drop the old table and rename the new table
 DROP TABLE pin_messages;
 
 ALTER TABLE pin_messages_new RENAME TO pin_messages;