fix: restructure can_redeem to gracefully handle error

[kiram15]

Description:
models.py: Separate the get_content_metadata fetch into its own try/except, catching HTTPError and raising ContentPriceNullException instead. This normalizes the exception type for all callers.

subsidy_access_policy.py: The original single try/except ContentPriceNullException block covered all three branches (resolved_policy, successful_redemptions, else) and always raised a RedemptionRequestException on failure. For a learner who has already redeemed, a missing catalog entry is a data/catalog mismatch that should not fail the request.

Jira:
ENT-11649

Merge checklist:

• ./manage.py makemigrations has been run
  • Note: This must be run if you modified any models.
    • It may or may not make a migration depending on exactly what you modified, but it should still be run.

Post merge:

• Ensure that your changes went out to the stage instance
• Deploy to prod instance

[Copilot]

Pull request overview

This PR restructures list-price fetching and error handling so can_redeem can treat missing catalog/metadata differently depending on whether the learner can redeem vs has already redeemed.

Changes:

• SubsidyAccessPolicy.get_list_price now wraps HTTPError from content-metadata fetch as ContentPriceNullException.
• can_redeem now uses separate error-handling paths for resolved_policy, successful_redemptions, and the non-redeemable/no-redemption case, avoiding request failure for already-redeemed content with missing catalog entries.
• Adds warning logging for the already-redeemed + missing price scenario.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
enterprise_access/apps/subsidy_access_policy/models.py	Normalizes metadata-fetch HTTP failures into ContentPriceNullException for list-price computation.
enterprise_access/apps/api/v1/views/subsidy_access_policy.py	Refactors can_redeem list-price logic to avoid failing requests for already-redeemed content when metadata is missing.

[Copilot]

In the successful_redemptions branch, a ContentPriceNullException now results in list_price_dict staying None (per the comment). However, the response serializer (SubsidyAccessPolicyCanRedeemElementResponseSerializer) defines list_price as a nested ListPriceResponseSerializer without allow_null=True, so returning None here will likely cause serialization errors/500s. Update the serializer to allow null list_price (and ensure the OpenAPI schema reflects this), or return a consistently-shaped list_price object that the serializer can represent.

Suggested change

	)
	)
	# Provide a structurally valid "null" list price so the response serializer
	# (which does not allow a null nested object) can still represent it.
	list_price_dict = make_list_price_dict(None, None)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.03%. Comparing base (dfdeddf) to head (9fd89a4).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #108      +/-   ##
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+ Coverage   84.01%   84.03%   +0.01%     
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  Files         144      144              
  Lines       12226    12236      +10     
  Branches     1170     1170              
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+ Hits        10272    10282      +10     
  Misses       1625     1625              
  Partials      329      329              

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[brobro10000]

Once its merged, validate down stream consumers (course about page) is still receiving the expected messaging related to subsidy type, and catalog inclusion 👍🏽 . I would wait for either @pwnage101 or @iloveagent57 for final approval, but looks good on my end.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

[Copilot]

get_list_price() now normalizes HTTPError into ContentPriceNullException, but get_list_price_for_content(..., content_metadata=...) can still raise KeyError/ValueError (e.g., missing content_price, content_price=None, or non-int types) which will bypass the intended normalized exception path and can surface as a 500 to callers. Consider validating the fetched metadata and/or catching these errors and re-raising ContentPriceNullException so callers only have to handle one failure type.

[Copilot]

In the HTTPError handler for the enterprise-catalog metadata fetch, the log message drops both content_key and the exception details (except HTTPError: without as exc). This makes it hard to diagnose which content caused the failure and why in production. Consider logging the exception (or exc_info=True) and including content_key in the message/args.

Suggested change

	except HTTPError:
	# We might normally re-raise the exception here (and have in the past), but this would cause
	# can-redeem requests to fail for courses which contain restricted runs where the customer does
	# not have restricted access. The desired behavior is for the request to NOT fail, and the
	# frontend is already coded to discard the restricted runs.
	logger.warning(
	(
	'Failed to obtain content metadata from enterprise-catalog with enterprise customer '
	'%s. This can happen if the run is restricted.'
	),
	enterprise_customer_uuid
	except HTTPError as exc:
	# We might normally re-raise the exception here (and have in the past), but this would cause
	# can-redeem requests to fail for courses which contain restricted runs where the customer does
	# not have restricted access. The desired behavior is for the request to NOT fail, and the
	# frontend is already coded to discard the restricted runs.
	logger.warning(
	(
	'Failed to obtain content metadata from enterprise-catalog for content_key %s with '
	'enterprise customer %s. This can happen if the run is restricted.'
	),
	content_key,
	enterprise_customer_uuid,
	exc_info=True,