When navigating gated content, the previous and next buttons stop working

[mariajgrimaldi]

Description

When navigating gated content, the previous and next buttons stop working so the user can't go to previous/next subsections.

Expected behavior

As a learner, upon navigating to a gated unit, you should see a message about completing the prerequisite, and both the "Previous" and "Next" buttons should function correctly.

Actual behavior

As a learner, when you navigate to a gated unit, you see the message prompting you to complete the prerequisite, but the "Previous" and "Next" buttons do not work.
https://jam.dev/c/4f02a831-969b-4c18-beab-378b45a09e9e

Steps to reproduce

1. Log in as a learner and navigate to a unit that is gated by the prerequisite.
2. Observe the message about completing the prerequisite and attempt to use the "Previous" and "Next" buttons.

Originally reported here: openedx/wg-build-test-release#414

[mariajgrimaldi]

I could reproduce this after doing the following:

1. Configuring a subsection as a prerequisite
2. Making that subsection the prerequisite of another subsection
3. Go to the prerequisite subsection and navigate to the gated subsection
4. If I try to go to the previous unit right before the gated subsection, the sequence buttons stop working for some reason
5. If from the sidebar I try entering one of the units in the gated subsection, and the previous button works

Here's a video:

Screencast.from.02-12-24.18.53.14.webm

[bradenmacdonald]

Does this relate to #1429 at all?

[mariajgrimaldi]

@bradenmacdonald: I'm not sure, but I asked my team for help looking into it. Hopefully, they'll have some ideas soon.

[mariajgrimaldi]

FYI @farhaanbukhsh

[jignaciopm]

First update

After seeing the behavior of the URLs once you go to a gated subsection with the help of the navigation buttons, I was able to verify the following:

When passing between two normal subsections, the URL of the next button is formed by adding /first to the url of the sequential (subsection), for example:

http://apps.local.openedx.io/learning/course/course-v1:OpenedX+DemoX+DemoCourse/block-v1:OpenedX+DemoX+DemoCourse+type@sequential+block@54bed3d4d5854713bde4300681fb7d18/first

After this, it is redirected to the vertical URL (unit)

http://apps.local.openedx.io/learning/course/course-v1:OpenedX+DemoX+DemoCourse/block-v1:OpenedX+DemoX+DemoCourse+type@sequential+block@54bed3d4d5854713bde4300681fb7d18/block-v1:OpenedX+DemoX+DemoCourse+type@vertical+block@8fcb212dfd4c48afb62e0b04edc8d4fe

Although the next button from a normal subsection to a gated one is also formed by adding the /first

http://apps.local.openedx.io/learning/course/course-v1:OpenedX+DemoX+DemoCourse/block-v1:OpenedX+DemoX+DemoCourse+type@sequential+block@7bbcf252a0f840a3b11672d9caaa7631/first

However, in the redirection the vertical URL is not being added, but rather it is staying at the sequential URL

http://apps.local.openedx.io/learning/course/course-v1:OpenedX+DemoX+DemoCourse/block-v1:OpenedX+DemoX+DemoCourse+type@sequential+block@7bbcf252a0f840a3b11672d9caaa7631

What I imagine is that when a subsection is gated, the API does not return the units when you move towards it using the navigation buttons, which does happen when you click on the side menu, since these are supposed to be blocked and are not required to be rendered, so it does not allow the correct redirection URL to be formed and for this reason it does not know where it is in the course outline and cannot render the correct URLs in the navigation buttons.

Currently, we continue reviewing the code to verify the hypothesis 100%.

We will continue to notify you about progress in this same way.

CC @magajh