From 4befae9f1e290a869d927828cff2cd71d1c7891e Mon Sep 17 00:00:00 2001
From: MAEDA Go <maeda@farend.jp>
Date: Sun, 23 Aug 2026 15:06:10 +0900
Subject: [PATCH] Delete workflow rules referring to an issue custom field when
 the custom field is deleted (#44366).

---
 app/models/issue_custom_field.rb                   |  7 +++++++
 ...ete_orphaned_workflow_rules_of_custom_fields.rb | 14 ++++++++++++++
 test/unit/issue_custom_field_test.rb               |  9 +++++++++
 3 files changed, 30 insertions(+)
 create mode 100644 db/migrate/20260823000000_delete_orphaned_workflow_rules_of_custom_fields.rb

diff --git a/app/models/issue_custom_field.rb b/app/models/issue_custom_field.rb
index ae460e221..b9d067956 100644
--- a/app/models/issue_custom_field.rb
+++ b/app/models/issue_custom_field.rb
@@ -24,10 +24,17 @@ class IssueCustomField < CustomField
   safe_attributes 'project_ids',
                   'tracker_ids'

+  before_destroy :delete_workflow_rules
+
   def type_name
     :label_issue_plural
   end

+  # Deletes workflow rules that refer to this custom field
+  def delete_workflow_rules
+    WorkflowRule.where(:field_name => id.to_s).delete_all
+  end
+
   def visible_by?(project, user=User.current)
     super || roles.intersect?(user.roles_for_project(project))
   end
diff --git a/db/migrate/20260823000000_delete_orphaned_workflow_rules_of_custom_fields.rb b/db/migrate/20260823000000_delete_orphaned_workflow_rules_of_custom_fields.rb
new file mode 100644
index 000000000..4148cd35e
--- /dev/null
+++ b/db/migrate/20260823000000_delete_orphaned_workflow_rules_of_custom_fields.rb
@@ -0,0 +1,14 @@
+class DeleteOrphanedWorkflowRulesOfCustomFields < ActiveRecord::Migration[8.1]
+  def up
+    field_names = WorkflowRule.where("field_name IS NOT NULL").distinct.pluck(:field_name)
+    custom_field_ids = field_names.select {|name| name =~ /\A\d+\z/}.map(&:to_i)
+    orphaned_ids = custom_field_ids - CustomField.where(id: custom_field_ids).pluck(:id)
+    if orphaned_ids.any?
+      WorkflowRule.where(field_name: orphaned_ids.map(&:to_s)).delete_all
+    end
+  end
+
+  def down
+    # no-op
+  end
+end
diff --git a/test/unit/issue_custom_field_test.rb b/test/unit/issue_custom_field_test.rb
index d8c9c790a..dde72efd8 100644
--- a/test/unit/issue_custom_field_test.rb
+++ b/test/unit/issue_custom_field_test.rb
@@ -43,4 +43,13 @@ class IssueCustomFieldTest < ActiveSupport::TestCase
     field.save!
     assert_equal 0, field.roles.count
   end
+
+  def test_destroy_should_delete_workflow_rules
+    field = IssueCustomField.create!(:name => 'Field', :field_format => 'string')
+    WorkflowPermission.create!(:role_id => 1, :tracker_id => 1, :old_status_id => 1, :field_name => field.id.to_s, :rule => 'required')
+    assert_equal 1, WorkflowRule.where(:field_name => field.id.to_s).count
+
+    field.destroy
+    assert_equal 0, WorkflowRule.where(:field_name => field.id.to_s).count
+  end
 end
--
2.55.0