fix(files): allow GC through storage protect_delete

(cherry picked from commit a6eff7ad124c94c75751c77a499433b562911b7b)

volumes/db/cc/75-files-gc-protect-delete.sql

@@ -0,0 +1,51 @@
+-- Allow our file-GC helpers to satisfy Supabase storage.protect_delete
+-- without weakening the managed storage trigger for arbitrary raw deletes.
+--
+-- Supabase storage.protect_delete permits direct storage.objects deletes only
+-- when the transaction-local GUC storage.allow_delete_query is 'true'.  The
+-- Storage API sets that GUC for its own deletes.  public.files GC is our
+-- trigger-side cleanup path, so scope the same GUC to these SECURITY DEFINER
+-- helpers immediately before their storage.objects DELETE statements.
+
+create or replace function public._delete_storage_objects(p_bucket text, p_path text)
+returns void
+language plpgsql security definer
+set search_path to 'public', 'storage'
+as $$
+begin
+  if p_bucket is null or p_path is null then
+    return;
+  end if;
+
+  perform set_config('storage.allow_delete_query', 'true', true);
+
+  delete from storage.objects where bucket_id = p_bucket and name = p_path;
+  delete from storage.objects where bucket_id = p_bucket and name like p_path || '/%';
+end
+$$;
+
+create or replace function public._delete_storage_prefix(p_bucket text, p_prefix text)
+returns void
+language plpgsql security definer
+set search_path to 'public', 'storage'
+as $$
+begin
+  if p_bucket is null or p_prefix is null then
+    return;
+  end if;
+
+  perform set_config('storage.allow_delete_query', 'true', true);
+
+  -- Delete any objects whose name starts with the prefix + '/'
+  delete from storage.objects where bucket_id = p_bucket and name like p_prefix || '/%';
+  -- In case an object exists exactly at the prefix (rare but safe)
+  delete from storage.objects where bucket_id = p_bucket and name = p_prefix;
+end
+$$;
+
+-- These helpers are intended for our SECURITY DEFINER GC triggers/helpers, not
+-- as a general SQL delete API for application roles.
+revoke all on function public._delete_storage_objects(text, text) from public;
+revoke all on function public._delete_storage_prefix(text, text) from public;
+revoke all on function public._delete_storage_objects(text, text) from anon, authenticated;
+revoke all on function public._delete_storage_prefix(text, text) from anon, authenticated;