Redmine

I have done some testing for this issue. I am able to reproduce the described behavior:

• Environment:
  • Redmine 2.3.1.devel.11845 (trunk)
  • Ruby 1.9.3 & 2.0.0 [x86_64-linux]
  • Rails 3.2.13
  • Database adapter: Mysql2
  • Redmine plugins: no plugins installed

• Steps to reproduce:
1. Load Redmine default config
2. Create new issue
3. Assign the new issue an assignee (e.g. admin)
4. Update/edit the issue (but don't submit the form)
   1. Change the value of the assignee field (<< me >> is sufficient for this use-case)
   2. Change the tracker or status field value (which - as expected - triggers an Ajax request)

• Current behavior:
  • After 4.2: the assignee field value is reset from the new value (<< me >>, see 4.1) to the old value (admin, see 3)
• Expected behavior:
  • After 4.2: the assignee field value is kept (still << me >>, see 4.1)

• Random trace (without errors)Random trace (without errors)

  Started GET "/issues/16" for xxx.xxx.xxx.xxx at 2013-05-25 00:10:50 +0200
  Processing by IssuesController#show as HTML
    Parameters: {"id"=>"16"}
    Current user: admin (id=1)
    Rendered issues/_action_menu.html.erb (5.8ms)
    Rendered issue_relations/_form.html.erb (2.2ms)
    Rendered issues/_relations.html.erb (3.9ms)
    Rendered issues/_history.html.erb (36.4ms)
    Rendered issues/_action_menu.html.erb (4.9ms)
    Rendered issues/_form_custom_fields.html.erb (0.1ms)
    Rendered issues/_attributes.html.erb (24.7ms)
    Rendered issues/_form.html.erb (45.7ms)
    Rendered attachments/_form.html.erb (2.5ms)
    Rendered issues/_edit.html.erb (63.1ms)
    Rendered issues/_sidebar.html.erb (5.5ms)
    Rendered watchers/_watchers.html.erb (5.6ms)
    Rendered issues/show.html.erb within layouts/base (162.6ms)
  Completed 200 OK in 276ms (Views: 169.0ms | ActiveRecord: 37.0ms)
  Started PUT "/projects/test-2/issues/update_form.js?id=16" for xxx.xxx.xxx.xxx at 2013-05-25 00:11:09 +0200
  Processing by IssuesController#update_form as JS
    Parameters: {"utf8"=>"✓", "authenticity_token"=>"<<token>>", "issue"=>{"is_private"=>"0", "project_id"=>"5", "tracker_id"=>"1", "subject"=>"8", "description"=>"", "status_id"=>"2", "priority_id"=>"3", "assigned_to_id"=>"1", "fixed_version_id"=>"10", "parent_issue_id"=>"", "start_date"=>"2013-05-05", "due_date"=>"", "estimated_hours"=>"", "done_ratio"=>"0", "notes"=>"", "private_notes"=>"0", "lock_version"=>"7"}, "time_entry"=>{"hours"=>"", "activity_id"=>"", "comments"=>""}, "last_journal_id"=>"78", "id"=>"16", "project_id"=>"test-2"}
    Current user: admin (id=1)
    Rendered issues/_form_custom_fields.html.erb (5.9ms)
    Rendered issues/_attributes.html.erb (35.3ms)
    Rendered issues/_form.html.erb (47.4ms)
    Rendered issues/update_form.js.erb (49.0ms)
  Completed 200 OK in 127ms (Views: 44.2ms | ActiveRecord: 17.4ms)