fix: always define a student_data_store to prevent errors on XBlock load [FC-0076]

[rpenido]

Description

This PR adds a DictFieldData to the student_data_store if the user is not defined.

Additional Information

More info here: openedx/XBlock#815 (comment)

This fixes an error on the meilisearch index update after saving the Survey Xblock.

cms-1          | 2025-01-28 19:36:18,402 ERROR 2163 [celery_utils.logged_task] [user 4] [ip 172.18.0.1] logged_task.py:48 - [9d7cda4b-afd2-404f-a39c-7a185c486907] failed due to Traceback (most recent call last):
cms-1          |   File "/openedx/venv/lib/python3.11/site-packages/celery/app/trace.py", line 453, in trace_task
cms-1          |     R = retval = fun(*args, **kwargs)
cms-1          |                  ^^^^^^^^^^^^^^^^^^^^
cms-1          |   File "/openedx/venv/lib/python3.11/site-packages/celery/app/autoretry.py", line 38, in run
cms-1          |     return task._orig_run(*args, **kwargs)
cms-1          |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cms-1          |   File "/openedx/venv/lib/python3.11/site-packages/edx_django_utils/monitoring/internal/code_owner/utils.py", line 195, in new_function
cms-1          |     return wrapped_function(*args, **kwargs)
cms-1          |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cms-1          |   File "/openedx/edx-platform/openedx/core/djangoapps/content/search/tasks.py", line 57, in upsert_library_block_index_doc
cms-1          |     api.upsert_library_block_index_doc(usage_key)
cms-1          |   File "/openedx/edx-platform/openedx/core/djangoapps/content/search/api.py", line 639, in upsert_library_block_index_doc
cms-1          |     searchable_doc_for_library_block(library_block_metadata)
cms-1          |   File "/openedx/edx-platform/openedx/core/djangoapps/content/search/documents.py", line 381, in searchable_doc_for_library_block
cms-1          |     block = xblock_api.load_block(xblock_metadata.usage_key, user=None)
cms-1          |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cms-1          |   File "/openedx/edx-platform/openedx/core/djangoapps/xblock/api.py", line 117, in load_block
cms-1          |     return runtime.get_block(usage_key, version=version)
cms-1          |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cms-1          |   File "/openedx/edx-platform/openedx/core/djangoapps/xblock/runtime/learning_core_runtime.py", line 229, in get_block
cms-1          |     block.force_save_fields(block._get_fields_to_save())  # pylint: disable=protected-access
cms-1          |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
cms-1          |   File "/mnt/xblock/xblock/core.py", line 531, in force_save_fields
cms-1          |     self._field_data.set_many(self, fields_to_save_json)
cms-1          |   File "/mnt/xblock/xblock/field_data.py", line 164, in set_many
cms-1          |     field_data.set_many(block, new_update_dict)
cms-1          |     ^^^^^^^^^^^^^^^^^^^
cms-1          | AttributeError: 'NoneType' object has no attribute 'set_many'

The underlying issue is that the mutable fields are written on XBlock load, even if they are from user_state scope, as in the example of the Survey XBlock above:

cms-1          | block._get_fields_to_save() ['feedback', 'max_submissions', 'private_results', 'answers', 'block_name', 'choices', 'display_name', 'questions']

As the LearningCoreXBlockRuntime doesn't had the Scope.user_state before, the get_block function throws an error.

Testing instructions

• Edit a Survey block on the Library Authoring page and check the error above
• Checkout the current PR and mount it on your tutor stack
• Check that the error is gone and the block document is updated successfully

---

Private ref: FAL-4033

[openedx-webhooks]

Thanks for the pull request, @rpenido!

This repository is currently maintained by @openedx/wg-maintenance-edx-platform.

Once you've gone through the following steps feel free to tag them in a comment and let them know that your changes are ready for engineering review.

🔘 Get product approval

If you haven't already, check this list to see if your contribution needs to go through the product review process.

• If it does, you'll need to submit a product proposal for your contribution, and have it reviewed by the Product Working Group.
  • This process (including the steps you'll need to take) is documented here.
• If it doesn't, simply proceed with the next step.

🔘 Provide context

To help your reviewers and other members of the community understand the purpose and larger context of your changes, feel free to add as much of the following information to the PR description as you can:

• Dependencies

  This PR must be merged before / after / at the same time as ...

• Blockers

  This PR is waiting for OEP-1234 to be accepted.

• Timeline information

  This PR must be merged by XX date because ...

• Partner information

  This is for a course on edx.org.

• Supporting documentation
• Relevant Open edX discussion forum threads

🔘 Get a green build

If one or more checks are failing, continue working on your changes until this is no longer the case and your build turns green.

---

Where can I find more information?

If you'd like to get more details on all aspects of the review process for open source pull requests (OSPRs), check out the following resources:

• Overview of Review Process for Community Contributions
• Pull Request Status Guide
• Making changes to your pull request

When can I expect my changes to be merged?

Our goal is to get community contributions seen and reviewed as efficiently as possible.

However, the amount of time that it takes to review and merge a PR can vary significantly based on factors such as:

• The size and impact of the changes that it introduces
• The need for product review
• Maintenance status of the parent repository

💡 As a result it may take up to several weeks or months to complete a review and merge your PR.

[pomegranited]

👍 Works for me, thank you @rpenido !

Do we need to bump the XBlock dependency too?

• I tested this with fix: throw an error if the scope if None on scope_mappings [FC-0076] XBlock#815 using the PR test instructions.
• I read through the code
• I checked for accessibility issues N/A
• Includes documentation N/A
• User-facing strings are extracted for translation N/A

[rpenido]

Thanks @pomegranited!

Do we need to bump the XBlock dependency too?

The PRs are complementary, so I think we don't need to hold this PR while waiting for the release of the other change.

If the other PR gets merged first, I'll bump the version here.

[rpenido]

Hi @bradenmacdonald!
I rebased this PR, bumped the XBlock version and tested it again.
I think it is good to merge!

[bradenmacdonald]

@rpenido Great! I'll merge it tomorrow morning

[edx-pipeline-bot]

2U Release Notice: This PR has been deployed to the edX staging environment in preparation for a release to production.

[edx-pipeline-bot]

2U Release Notice: This PR has been deployed to the edX production environment.

[edx-pipeline-bot]

2U Release Notice: This PR has been deployed to the edX production environment.