Breaking: #73698 - Streamline layout of FlashMessages

See forge#73698


The layout and usage of FlashMessages has been streamlined in the TYPO3 backend. All FlashMessages in the TYPO3 backend are now rendered as <div> markup and contain an icon, the message and an optional title.


<div class="alert alert-danger">
   <div class="media">
      <div class="media-left">
         <span class="fa-stack fa-lg">
            <i class="fa fa-circle fa-stack-2x"></i>
            <i class="fa fa-times fa-stack-1x"></i>
      <div class="media-body">
         <h4 class="alert-title">The optional title</h4>
         <p class="alert-message">The message goes here</p>

FlashMessages that are used as inline notification should be removed and replaced with custom HTML code. For the core we have defined output and usage for messages:

1) FlashMessages

FlashMessages are designed to inform a user about success or failure of an action, which was triggered by the user. Example: If the user deletes a record, a FlashMessage informs the user about success or failure. This kind of information is not static, it is a temporary and volatile information and triggered by a user action.

Keep in mind that you must not use HTML markup here, since this information might be shown in a context different from HTML, like processing it via Javascript or showing the message on the command line.

2) Callouts (InfoBox-ViewHelper)

Callouts are designed to display permanent information, a very good example is the usage in the Page-Module. If a user opens a system folder with the page module, the callout explains: 'Hey, you try to use the page module on a sys folder, please switch to the list module'. This ViewHelper can also be used to show some help or instruction how to use a backend module.

3) Any other information

For any other information e.g. a list of files which has changed, must be handled in the action / view of the module or plugin. This is not a use case for a FlashMessage or Callout! Example: Display a list of a hundred files within a FlashMessage or Callout is a bad idea, build custom markup in the view to handle this kind of message.


Extensions which use the FlashMessageViewHelper with the default rendering will now get a list of <div>-messages instead of a <ul>-list.


No migration needed, the generated output should be as expected. If the rendering is broken please consider about the correct usage of FlashMessages and read the explanation about message types above.