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  1. Moodle
  2. MDL-59148

Use fallback CSS whilst waiting for CSS to build

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Details

    • MOODLE_34_STABLE
    • MOODLE_34_STABLE
    • MDL-59148-master-7
    • Hide
      Setup
      1. Open your browsers dev tools to their network tab, filtered to 'styles.php'
      2. Disable the browser cache and, if possible, enable the "Preserve log" function to assist you
      Generic tests
      1. Refresh the page
      2. Purge your caches and refresh the page (or press the "Purge all caches" link)
        1. Confirm that there was a single request to styles.php which returned straight away
        2. Confirm that the page fully rendered and that the call to styles.php looks to have finished
      3. Navigate to another page
        1. Confirm that there was a single request to styles.php which returned straight away
        2. Confirm that the theme looks as anticipated, including language direction
      RTL Langauge
      1. Switch to an RTL language
      2. Run the Generic tests again
      3. Switch between LTR + RTL langauges without a cache purge, confirming that you get the correct stylesheet each time
      Alternative theme test
      1. Repeat all of the above tests with the More and Clean themes.
      Brownie test
      1. Add error_log calls to theme/styles.php around the fallback handling and:
        1. see if you can understand how it works
        2. ensure that if one fallback process starts the queueing process, that another just skips the process entirely because it's unable to get the lock
      Changes test
      1. Make a change to something obvious in your theme (e.g. colour) and save changes
        1. Confirm that there was a single request to styles.php which returned straight away
        2. Confirm that the page fully rendered and that the call to styles.php looks to have finished
      2. Wait a while for the theme to generate and navigate to a different page
      3. Make a change to something obvious in your theme (e.g. colour) and save changes
        1. Confirm that the change was present
        2. Confirm that there was a single request to styles.php which returned straight away
      Show
      Setup Open your browsers dev tools to their network tab, filtered to 'styles.php' Disable the browser cache and, if possible, enable the "Preserve log" function to assist you Generic tests Refresh the page Purge your caches and refresh the page (or press the "Purge all caches" link) Confirm that there was a single request to styles.php which returned straight away Confirm that the page fully rendered and that the call to styles.php looks to have finished Navigate to another page Confirm that there was a single request to styles.php which returned straight away Confirm that the theme looks as anticipated, including language direction RTL Langauge Switch to an RTL language Run the Generic tests again Switch between LTR + RTL langauges without a cache purge, confirming that you get the correct stylesheet each time Alternative theme test Repeat all of the above tests with the More and Clean themes. Brownie test Add error_log calls to theme/styles.php around the fallback handling and: see if you can understand how it works ensure that if one fallback process starts the queueing process, that another just skips the process entirely because it's unable to get the lock Changes test Make a change to something obvious in your theme (e.g. colour) and save changes Confirm that there was a single request to styles.php which returned straight away Confirm that the page fully rendered and that the call to styles.php looks to have finished Wait a while for the theme to generate and navigate to a different page Make a change to something obvious in your theme (e.g. colour) and save changes Confirm that the change was present Confirm that there was a single request to styles.php which returned straight away

    Description

      When serving Just-in-time compiled themes, we should serve a fallback version of the theme while it is compiling.

      1. if the theme is currently available in localcache for the requested revision, serve it immediately and stop.
      2. if the theme revision is found in MUC, copy it to localcache, serve it immediately and stop.
      3. if there's a previous copy of the the theme, serve it now and do not die;
      4. attempt to get a lock for the theme generation
        1. if the fallback was served and it was not possible to get a lock, die immediately - there is no point generating the theme as it won't be served anyway.
      5. generate the new theme instance
      6. if the fallback was served, die immediately - there is no point serving the newly generated theme as the client has closed the connection.
      7. serve the newly generated theme

      Attachments

        Issue Links

          blocks

          Task - A task that needs to be completed. Tasks usually refer to work that must be done outside the product. MDL-59144 As a hosting provider, I want to reset local cache without causing CPU spikes

          • Minor - Minor loss of function where workaround is possible
          • Closed

          Task - A task that needs to be completed. Tasks usually refer to work that must be done outside the product. MDL-59184 Kill off CSS chunking and non-SVG support

          • Minor - Minor loss of function where workaround is possible
          • Closed
          has a non-specific relationship to

          Bug - A problem which impairs or prevents Moodle from functioning correctly. MDL-59461 Notify when serving outdated scss

          • Minor - Minor loss of function where workaround is possible
          • Closed

          Improvement - An enhancement to an existing Moodle feature. MDL-59123 Compile SCSS files on the command-line

          • Minor - Minor loss of function where workaround is possible
          • Closed
          is blocked by

          Bug - A problem which impairs or prevents Moodle from functioning correctly. MDL-59142 Cache post-processed CSS in MUC

          • Minor - Minor loss of function where workaround is possible
          • Closed

          Task - A task that needs to be completed. Tasks usually refer to work that must be done outside the product. MDL-59147 Store last successful compilation in tempdir

          • Minor - Minor loss of function where workaround is possible
          • Closed
          is duplicated by

          Bug - A problem which impairs or prevents Moodle from functioning correctly. MDL-57387 When scss fails to compile, we should fall back to something good

          • Minor - Minor loss of function where workaround is possible
          • Closed
          will help resolve

          Task - A task that needs to be completed. Tasks usually refer to work that must be done outside the product. MDL-59145 As a user, I want to interact with the page, before CSS is fully ready

          • Minor - Minor loss of function where workaround is possible
          • Closed

          Task - A task that needs to be completed. Tasks usually refer to work that must be done outside the product. MDL-59310 Use fallback CSS whilst waiting for CSS to build (backport of MDL-59148)

          • Minor - Minor loss of function where workaround is possible
          • Closed

          Activity

            People

              dobedobedoh Andrew Lyons
              dobedobedoh Andrew Lyons
              Ryan Wyllie Ryan Wyllie
              David Monllaó David Monllaó
              David Monllaó David Monllaó
              Matteo Scaramuccia, David Woloszyn, Huong Nguyen, Jake Dallimore, Meirza, Michael Hawkins, Raquel Ortega, Safat Shahin, Stevani Andolo, Huong Nguyen, Bas Brands, Mathew May, Amaia Anabitarte, Carlos Escobedo, Laurent David, Mikel Martín Corrales, Sabina Abellan, Sara Arjona (@sarjona)
              Votes:
              2 Vote for this issue
              Watchers:
              8 Start watching this issue

              Dates

                Created:
                Updated:
                Resolved:
                13/Nov/17