From e5d8166a12bc5db2f15afa8f2573be6892481e01 Mon Sep 17 00:00:00 2001
From: aschmitz <andy.schmitz@gmail.com>
Date: Wed, 11 Oct 2017 14:20:39 -0500
Subject: [PATCH] Fix #5329 (#5332)
This fixes #5329, which occurred when using MigrationHelpers on a
table that Postgres estimated to be non-empty when it was actually
empty.
---
lib/mastodon/migration_helpers.rb | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/lib/mastodon/migration_helpers.rb b/lib/mastodon/migration_helpers.rb
index ed716501e..80a8f440c 100644
--- a/lib/mastodon/migration_helpers.rb
+++ b/lib/mastodon/migration_helpers.rb
@@ -335,7 +335,10 @@ module Mastodon
start_arel = table.project(table[:id]).order(table[:id].asc).take(1)
start_arel = yield table, start_arel if block_given?
- start_id = exec_query(start_arel.to_sql).to_hash.first['id'].to_i
+ first_row = exec_query(start_arel.to_sql).to_hash.first
+ # In case there are no rows but we didn't catch it in the estimated size:
+ return unless first_row
+ start_id = first_row['id'].to_i
say "Migrating #{table_name}.#{column} (~#{total.to_i} rows)"