This bug was introduced in#41168.

Best viewed with:https://github.com/symfony/symfony/pull/41346/files?w=1 - we could also remove the new indentation inexception.js.

In that PR, we innocently don't reloadSfjs if it doesn't exist. However, on an error page, that template ALSO adds anSfjs, and thatSfjs issmaller - containing only a subset of theSfjs functions. This is tricky, but this PR fixes it.

Here are the various situations:

1. I hit an exception page. TheSfjs fromexception.js is loaded first. This adds the smallerSfjs. Then thebase_js.html.twig version is hit. BecauseSfjs is missing theloadToolbar() method, that code DOES run again to reinitialize it.

2. I am on a normal page, then travel to an exception page with Turbo. In this case, the originalSfjs frombase_js.html.twig was processed. Then, on the exception page, theSfjs fromexception.js is ignored, as is the 2nd execution ofbase_js.html.twig.

Overall, the JS could use some work for supporting things like Turbo (e.g.DOMContentLoaded doesn't work with Turbo, so the exception page JS is broken). But I wanted to focus on fixing the bug in this PR.

As a reminder,#41168 (avoiding overridingSfjs) was done to help with the AJAX toolbar and Turbo - it's explained in point (1) on#41168.

Cheers!