Fixed empty variable issue in header template

- fixes #8942

CHANGELOG.txt

@@ -90,6 +90,7 @@ Changelog
  * Remove `is_parent` kwarg in various page button hooks as this approach is no longer required (Paarth Agarwal)
  * Improve security of redirect imports by adding a file hash (signature) check for so that any tampering of file contents between requests will throw a `BadSignature` error (Jaap Roes)
  * Refresh designs for Home (Dashboard) site summary panels, use theme spacing and colours, add support for RTL layouts and better support for small devices (Paarth Agarwal, LB (Ben) Johnston)
+ * Include all CSS system colors in allowed values in Stylelint's declaration-strict-value rule
  * Fix: Typo in `ResumeWorkflowActionFormatter` message (Stefan Hammer)
  * Fix: Throw a meaningful error when saving an image to an unrecognised image format (Christian Franke)
  * Fix: Remove extra padding for headers with breadcrumbs on mobile viewport (Steven Steinwand)
@@ -125,7 +126,7 @@ Changelog
  * Fix: Avoid 503 `AttributeError` when an empty search param `q=` is combined with other filters in the Images index view (Paritosh Kabra)
  * Fix: Fix error with string representation of FormSubmission not returning a string (LB (Ben) Johnston)
  * Fix: Ensure disabled buttons are distinguishable from active buttons in forced colors mode (Anuja Verma)
- * Include all CSS system colors in allowed values in Stylelint's declaration-strict-value rule
+ * Fix: Revise usage of `extra_actions` in new changes to shared header template to avoid invalid template variable usage (Paarth Agarwal)
 
 
 3.0.1 (16.06.2022)

docs/releases/4.0.md

@@ -70,8 +70,9 @@ The bulk of these enhancements have been from Paarth Agarwal, who has been doing
    * Remove legacy (non-next) breadcrumbs no longer used, remove `ModelAdmin` usage of breadcrumbs completely and adopt consistent 'back' link approach
  * Headers
    * Update classes and styles for the shared header templates to align with UI guidelines
+   * Ensure the shared header template is more reusable, add ability to include classes, extra content and other blocks
    * Switch all report workflow, redirects, form submissions, site settings views to use Wagtail’s reusable header component
-   * Resolve issues throughout Wagtail where the sidebar toggle would overlap content on small devices
+   * Resolve issues throughout Wagtail where the sidebar toggle would overlap header content on small devices
  * Tabs
    * Add Tabs to the Wagtail pattern library
    * Adopt new Tabs component in the workflow history report page, removing the bespoke implementation there

wagtail/admin/templates/wagtailadmin/shared/header.html

@@ -56,7 +56,9 @@
                     </div>
                 {% endif %}
             {% endblock %}
-            {{ extra_actions }}
+            {% if extra_actions %}
+                {{ extra_actions }}
+            {% endif %}
         </div>
     </div>
     {% block extra_rows %}{% endblock %}