Redmine

Started PATCH "/users/3" for 127.0.0.1 at 2020-04-26 16:42:34 +0900
Processing by UsersController#update as HTML
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ActionView::Template::Error (no implicit conversion of nil into String):
     7:
     8: <%=
     9:   page_title = title [l(:label_user_plural), users_path], @user.login
    10:   page_title.insert(page_title.rindex(' ') + 1, avatar(@user))
    11: %>
    12:
    13: <%= render_tabs user_settings_tabs %>

app/views/users/edit.html.erb:10:in `insert'
app/views/users/edit.html.erb:10:in `_app_views_users_edit_html_erb___718898119020271380_70199616790460'
app/controllers/users_controller.rb:180:in `block (2 levels) in update'
app/controllers/users_controller.rb:179:in `update'
lib/redmine/sudo_mode.rb:64:in `sudo_mode'

Steps to reproduce:
1. Enable "Use Gravatar user icons" (Setting.gravatar_enabled)
2. Update any user with a blank email address from the Administration page
3. "Email cannot be blank" error is expected but actually you will encounter the exception