From 169a3d78d25831db1aeeadc625cd4d8cd3db4d75 Mon Sep 17 00:00:00 2001
From: Jakub Duchek <jakduch@seznam.cz>
Date: Wed, 19 Aug 2026 20:28:57 +0200
Subject: [PATCH] Fixes #471 - Tolerate absent duplicate indexes

Migration 020 now treats an already missing duplicate index as the desired state and continues removing the remaining redundant indexes.

Assisted-By: Codex 5.6 Sol High
---
 .../020_drop_duplicate_indices.rb             | 18 ++++++++-----
 test/persistence_migrations_test.rb           | 25 +++++++++++++++++++
 2 files changed, 37 insertions(+), 6 deletions(-)
 create mode 100644 test/persistence_migrations_test.rb

diff --git a/lib/dynflow/persistence_adapters/sequel_migrations/020_drop_duplicate_indices.rb b/lib/dynflow/persistence_adapters/sequel_migrations/020_drop_duplicate_indices.rb
index 8b8b87be..30351ab3 100644
--- a/lib/dynflow/persistence_adapters/sequel_migrations/020_drop_duplicate_indices.rb
+++ b/lib/dynflow/persistence_adapters/sequel_migrations/020_drop_duplicate_indices.rb
@@ -2,16 +2,22 @@
 
 Sequel.migration do
   up do
-    alter_table(:dynflow_actions) do
-      drop_index [:execution_plan_uuid, :id]
+    if indexes(:dynflow_actions).key?(:dynflow_actions_execution_plan_uuid_id_index)
+      alter_table(:dynflow_actions) do
+        drop_index [:execution_plan_uuid, :id]
+      end
     end
 
-    alter_table(:dynflow_execution_plans) do
-      drop_index :uuid
+    if indexes(:dynflow_execution_plans).key?(:dynflow_execution_plans_uuid_index)
+      alter_table(:dynflow_execution_plans) do
+        drop_index :uuid
+      end
     end
 
-    alter_table(:dynflow_steps) do
-      drop_index [:execution_plan_uuid, :id]
+    if indexes(:dynflow_steps).key?(:dynflow_steps_execution_plan_uuid_id_index)
+      alter_table(:dynflow_steps) do
+        drop_index [:execution_plan_uuid, :id]
+      end
     end
   end
 
diff --git a/test/persistence_migrations_test.rb b/test/persistence_migrations_test.rb
new file mode 100644
index 00000000..347564eb
--- /dev/null
+++ b/test/persistence_migrations_test.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require_relative 'test_helper'
+
+describe 'Sequel persistence migrations' do
+  let(:db) { Sequel.connect('sqlite:/') }
+  let(:migrations_path) { Dynflow::PersistenceAdapters::Sequel.migrations_path }
+
+  after do
+    db.disconnect
+  end
+
+  it 'tolerates duplicate indexes that are already absent' do
+    Sequel::Migrator.run(db, migrations_path, table: 'dynflow_schema_info', target: 19)
+    db.alter_table(:dynflow_actions) do
+      drop_index [:execution_plan_uuid, :id]
+    end
+
+    Sequel::Migrator.run(db, migrations_path, table: 'dynflow_schema_info', target: 20)
+
+    _(db.indexes(:dynflow_actions)).wont_include :dynflow_actions_execution_plan_uuid_id_index
+    _(db.indexes(:dynflow_execution_plans)).wont_include :dynflow_execution_plans_uuid_index
+    _(db.indexes(:dynflow_steps)).wont_include :dynflow_steps_execution_plan_uuid_id_index
+  end
+end