feat: Configured subsection prerequisites persist during course olx/xml export/import

[haftamuk]

Configured subsection prerequisites persist during course olx/xml export/import

Overview

This PR introduces support for subsection (sequential) prerequisites in the OLX course format. Course authors can define prerequisite relationships between subsections with configurable completion criteria including minimum score and completion percentage requirements. Currently this information is lost during course import/export. This PR ensures configured subsection prerequisites are persisted during course olx/xml export/import. It allows course authors to define prerequisite relationships, have them exported to OLX format, and finally, have them properly imported.

Problem Statement

Currently, Open edX supports to define prerequisite relationships between subsections in Studio. This enables course authors from enforcing learning pathways where students must complete certain subsections before accessing others, which is crucial for structured learning experiences. But when a course is exported (XML/OLX) all configured relationships of subsections are lost and authors has to do it again manually in studio. This is time consuming and error prone!

Proposed Solution

• Extend the element in OLX to support prerequisite definitions
• Maintain full backward compatibility with existing OLX courses

Key Files

1. Service Layer (xmodule/seq_block.py)

   • Adds prerequisite information to sequential XML for export.

2. Import Processing Layer (xmodule/modulestore/xml_importer.py)

   • Processes prerequisite relationships during course import

OLX Format

Prerequisite information attached to sequential xml element

<sequential 
required_content="91d0290972c4488db10d7ca3694e13ca" 
min_score="100" 
min_completion="100" 
... >
    <vertical url_name="some_vertical"/>
   ...
</sequential>

Subsection prerequisite configuration how-to

1. Settings -> Advanced -> Enable subsection prerequisites -> true

Note : Even after configuring a complete learning path for a course you can disable the gating feature by simply turning this in to false. Also, if you switch it back to true, all the previous configured learning path will appear with out further work. This means, switching this setting to true/false will not impact persisted learning path configuration, but will impact how the learner will interact with the course.

Note : When you export a course with this flag set to true, the exported XML will contain the information

<course cert_html_view_enabled="true" discussions_settings="{&quot;enable_graded_units&quot;: false, &quot;enable_in_context&quot;: true, &quot;provider_type&quot;: &quot;openedx&quot;, &quot;unit_level_visibility&quot;: true}" display_name="Saturday1"

enable_subsection_gating="true" 
end="null" language="en" start="2030-01-01T00:00:00Z">
  <chapter url_name="ca81aeb19a7f41a49f05a87c95fe299a"/>
  <chapter url_name="4d13584e169241bb890871bd44059d43"/>
  <wiki slug="Saturday1.Saturday1.Saturday1"/>
</course>

Later during import this setting will be applied to the destination course. This is also the case when it is set to false (the destination course will be enable_subsection_gating set to false)

2. Make a subsection to serve as a prerequisite

3. Use the subsection as a prerequisite for other subsection

How to test

python -Wd -m pytest -p no:randomly --ds=cms.envs.test ./xmodule/modulestore/tests/test_xml_importer.py::TestSequentialPrerequisitesImport::test_gating_api_calls

python -Wd -m pytest -p no:randomly --ds=cms.envs.test ./xmodule/tests/test_sequence.py::SequenceBlockTestCase::test_export_sequence_with_prerequisites

Linked Issue: #36995

Supporting information

1. Unit Prerequisites Lost During Course Export/Import #36995
2. https://discuss.openedx.org/t/request-for-comments-course-export-import-and-re-run/16508?u=haftamu.kebede

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[tecoholic]

@haftamuk Hi, the changes look good on the export side. I was able to verify that the <prerequisite> block is added to the output XML as expected. However, when I tried to reimport it in a new course, I ended up with this:

So, we are clearly missing the "import" part of the solution. Can you kindly add that functionality?

Additionally, I would recommend adding some unit test around the newly created functions. This is a very "core" part of the system and it's best to have unit tests in place.

[haftamuk]

So, we are clearly missing the "import" part of the solution. Can you kindly add that functionality?

Kindly see the import functionality is added!

[haftamuk]

Additionally, I would recommend adding some unit test around the newly created functions. This is a very "core" part of the system and it's best to have unit tests in place.

@tecoholic I will proceed to ensure existing unit tests pass and introduce new unit tests for the main changes made.
Thank you.

[tecoholic]

@haftamuk Thanks for updating the PR with the import implementation. It looks like you have used a Generative AI / LLM for the implementation and hence can't be used as is. Kindly consult the [official policy on use of LLMs for acceptable usage guidelines. In short, you can use it to experiment and create solutions, but the final code should be from the developer.

That doesn't mean we will have to discard this work. Let's use this as a base for the final solution.

I have an important request - for future work on this PR, please do not force-push changes. This will allow us to work ahead incrementally and rollback things if we end up doing something we don't want in the final solution. Kindly see my inline comments in the diff for specific details.

[tecoholic]

@haftamuk I realized, there is lot of things I have noted in comments. So, let's go step by step in addressing them

1. Just do a pass on cleaning up the single line changes like empty lines, comments..etc.,
2. Next, let's focus on the export XML format - this comment

Ping me for a review after that. Let's move on to the import part of the changes after that.

[tecoholic]

@Agrendalath Thank you for explaining things in detail.

[haftamuk]

Hello @Agrendalath ,
If you have time, if you can have a look at the PR if it is ready to merge!

Thank you very much.

[Agrendalath]

@tecoholic , would you be able to review this? I can review it as the CC in the next sprint, but I still have a few things to address in the current one.

cc: @haftamuk

[tecoholic]

@Agrendalath Absolutely. I will review it this sprint and you can do the CC in next.

[tecoholic]

@haftamuk This is looking great. I have a few more asks on the tests department. Can you kindly address those?

[tecoholic]

This tests only the happy path where the the mock_sequential has all the necessary values. More test cases convering the other code paths like the if conditional, the try...except block where the values are either missing or not in the expected format (int, string..etc) should be added to this test case.

[tecoholic]

Similar to the importer testcase, this only checks the happy path of the code. Let's add test cases where the 'if' conditions in add_prerequisite_to_xml produce other resutls as well.

[tecoholic]

@haftamuk 👍

• I tested this: I verified that the export and import of courses preserves pre-requisites in sequentials.
• I read through the code
• I checked for accessibility issues
• Includes documentation - Handled in a separate PR.

[haftamuk]

Hello @Agrendalath,
I am just trying to pull this to your visibility for a CC review.

Thank you

[tecoholic]

@Agrendalath Hi, a gentle reminder on taking a look at this PR.

[Agrendalath]

Sorry for the delay, @haftamuk, @tecoholic. I will review this later this week.