From: Jean-Philippe Lang <jp_lang@yahoo.fr>
Date: Mon, 13 Feb 2017 14:07:59 -0200
Subject: Bulk edit: show fields required after status/tracker change

Backported-by: Thomas Klose <thomas.klose@hiperscan.com>
Debian-Bug: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=852694
Original: http://www.redmine.org/projects/redmine/repository/revisions/15815

This patch must be dropped when upgrading Redmine to version 3.4+.
---
 app/controllers/issues_controller.rb | 25 +++++++++++++++++++++----
 app/views/issues/bulk_edit.html.erb  |  6 ++++--
 2 files changed, 25 insertions(+), 6 deletions(-)

--- a/app/controllers/issues_controller.rb
+++ b/app/controllers/issues_controller.rb
@@ -217,24 +217,41 @@ class IssuesController < ApplicationCont
       end
     end
 
+    edited_issues = Issue.where(:id => @issues.map(&:id)).to_a
+
     @allowed_projects = Issue.allowed_target_projects
     if params[:issue]
       @target_project = @allowed_projects.detect {|p| p.id.to_s == params[:issue][:project_id].to_s}
       if @target_project
         target_projects = [@target_project]
+        edited_issues.each {|issue| issue.project = @target_project}
       end
     end
     target_projects ||= @projects
 
+    @trackers = target_projects.map {|p| Issue.allowed_target_trackers(p) }.reduce(:&)
+    if params[:issue]
+      @target_tracker = @trackers.detect {|t| t.id.to_s == params[:issue][:tracker_id].to_s}
+      if @target_tracker
+        edited_issues.each {|issue| issue.tracker = @target_tracker}
+      end
+    end
+
     if @copy
       # Copied issues will get their default statuses
       @available_statuses = []
     else
-      @available_statuses = @issues.map(&:new_statuses_allowed_to).reduce(:&)
+      @available_statuses = edited_issues.map(&:new_statuses_allowed_to).reduce(:&)
     end
-    @custom_fields = @issues.map{|i|i.editable_custom_fields}.reduce(:&)
+    if params[:issue]
+      @target_status = @available_statuses.detect {|t| t.id.to_s == params[:issue][:status_id].to_s}
+      if @target_status
+        edited_issues.each {|issue| issue.status = @target_status}
+      end
+    end
+
+    @custom_fields = edited_issues.map{|i|i.editable_custom_fields}.reduce(:&)
     @assignables = target_projects.map(&:assignable_users).reduce(:&)
-    @trackers = target_projects.map {|p| Issue.allowed_target_trackers(p) }.reduce(:&)
     @versions = target_projects.map {|p| p.shared_versions.open}.reduce(:&)
     @categories = target_projects.map {|p| p.issue_categories}.reduce(:&)
     if @copy
@@ -242,7 +259,7 @@ class IssuesController < ApplicationCont
       @subtasks_present = @issues.detect {|i| !i.leaf?}.present?
     end
 
-    @safe_attributes = @issues.map(&:safe_attribute_names).reduce(:&)
+    @safe_attributes = edited_issues.map(&:safe_attribute_names).reduce(:&)
 
     @issue_params = params[:issue] || {}
     @issue_params[:custom_field_values] ||= {}
--- a/app/views/issues/bulk_edit.html.erb
+++ b/app/views/issues/bulk_edit.html.erb
@@ -43,14 +43,16 @@
   <label for="issue_tracker_id"><%= l(:field_tracker) %></label>
   <%= select_tag('issue[tracker_id]',
                  content_tag('option', l(:label_no_change_option), :value => '') +
-                   options_from_collection_for_select(@trackers, :id, :name, @issue_params[:tracker_id])) %>
+                   options_from_collection_for_select(@trackers, :id, :name, @issue_params[:tracker_id]),
+                   :onchange => "updateBulkEditFrom('#{escape_javascript url_for(:action => 'bulk_edit', :format => 'js')}')") %>
 </p>
 <% if @available_statuses.any? %>
 <p>
   <label for='issue_status_id'><%= l(:field_status) %></label>
   <%= select_tag('issue[status_id]',
                  content_tag('option', l(:label_no_change_option), :value => '') +
-                   options_from_collection_for_select(@available_statuses, :id, :name, @issue_params[:status_id])) %>
+                   options_from_collection_for_select(@available_statuses, :id, :name, @issue_params[:status_id]),
+                   :onchange => "updateBulkEditFrom('#{escape_javascript url_for(:action => 'bulk_edit', :format => 'js')}')") %>
 </p>
 <% end %>