Some improvements to the plugin

app/controller/subject_autocomplete_controller.rb

@@ -1,64 +1,52 @@
 # -*- coding: utf-8 -*-
 class SubjectAutocompleteController < ApplicationController
-
-  if Rails::VERSION::MAJOR >= 4
-    before_action :find_project, :init
-  else
-    before_filter :find_project, :init
-  end
-
-  def init
-    @issue_status_closed = IssueStatus.where('is_closed=?', true).pluck :id
-    @issue_status_open = IssueStatus.select('id').where('is_closed=?', false).pluck :id
-  end
+  before_action :find_project, only: :get_matches
 
   def get_matches
     # autocomplete for the issue subject field.
     limit_count = 15
     default_closed_past_days = 30
+
     # load closed tickets, show issue id
     @issues = []
     q = params[:term].to_s.strip
     if q.present?
-      if @project.nil?
-        scope = Issue.visible
-      else
-        if @project.parent
-          project_siblings = Project.where(:parent_id => @project.parent.id).map{|e| e.id }
-          project_siblings_children = Project.where(:parent_id => project_siblings).map{|e| e.id }
-          projects = project_siblings + project_siblings_children << @project.parent[:id]
-        else
-          project_children = Project.where(:parent_id => @project.id).map{|e| e.id }
-          projects = project_children << @project.id
-        end
-        scope = Issue.where(:project_id => projects).visible
+      scope = Issue.joins(:status, :project).visible
+
+      if @project.present?
+        scope = scope.where(@project.project_condition(true))
       end
-      if q.match(/\A#?(\d+)\z/)
-        @issues << scope.find_by_id($1.to_i)
+
+      if q =~ /\A#?(\d+)\z/
+        @issues << scope.find_by(id: ::Regexp.last_match(1).to_i)
       end
       past_days = params[:closed_past_days] ? params[:closed_past_days].to_i : default_closed_past_days
-      time_now = DateTime.now
-      # use ruby regexp. not all databases support regexp in sql
-      q = q.gsub(/[^a-zA-Z0-9# ]/, "").split(" ").map{|e|
-        e = Issue.connection.quote("%#{e}%")
-        "lower(#{Issue.table_name}.subject) like #{e}"}.join(" and ")
+
+      open_or_closed_in_past_days =
+        scope
+          .where({ issue_statuses: { is_closed: true } })
+          .where(
+            Issue.sanitize_sql_for_assignment(["issues.updated_on between ? and ?", past_days.days.ago, Time.current])
+          ).or(scope.open)
+
       @issues += scope
-        .where("#{q} and " +
-               "(issues.status_id in(?) or (issues.status_id in(?) and issues.updated_on between ? and ?))",
-               @issue_status_open, @issue_status_closed, time_now - past_days, time_now)
+        .like(q)
+        .and(open_or_closed_in_past_days)
         .order("#{Issue.table_name}.id desc")
         .limit(limit_count)
       @issues.compact!
       versions = {}
       Version.select("id,name").each{|e| versions[e.id] = e.name }
     end
+
     render :json => @issues.map {|e|
       label = "##{e[:id]} #{e[:subject]}"
       if e.fixed_version_id then label = "#{versions[e.fixed_version_id]} » #{label}" end
+
       {
         "label" => label,
         "value" => "",
-        "issue_url" => url_for(:controller => "issues", :action => "show", :id => e[:id]),
+        "issue_url" => issue_path(e),
         "is_closed" => e.closed?
       }
     }
@@ -67,9 +55,9 @@ def get_matches
   private
 
   def find_project
-    if params[:project_id].present?
-      @project = Project.find(params[:project_id])
-    end
+    return if params[:project_id].blank?
+
+    @project = Project.find(params[:project_id])
   rescue ActiveRecord::RecordNotFound
     render_404
   end

config/locales/ru.yml

@@ -0,0 +1,2 @@
+ru:
+  placeholder_text: "Тема / Поиск по существующим задачам"

config/routes.rb

@@ -1 +1 @@
-get "sbject_autocomplete/:action", controller: "subject_autocomplete"
+get "subject_autocomplete/get_matches", controller: "subject_autocomplete"

lib/redmine_subject_autocomplete/hooks.rb

@@ -3,7 +3,7 @@ module RedmineSubjectAutocomplete
   class Hooks < Redmine::Hook::ViewListener
     def view_issues_form_details_bottom(context)
 
-      path = (config.relative_url_root || '') + url_for({controller: 'subject_autocomplete', action: 'get_matches'}) + "?project_id=#{context[:project][:id]}"
+      path = url_for({controller: 'subject_autocomplete', action: 'get_matches', project_id: context.try(:[], :project).try(:[], :id)})
       translations = {
         "placeholder_text" => I18n.translate(:placeholder_text)
       }