fix: prevent duplicate enrolment report creation during sync

[sentry]

This PR addresses an IntegrityError: duplicate key value violates unique constraint "reports_enrolmentreport_enrolment_id_key" that occurs during the sync_enrolment_reports operation.

Problem:
The sync_enrolment_reports function, specifically the create_missing method, attempts to insert new EnrolmentReport instances into the database. In scenarios where multiple sync operations run concurrently (e.g., a cron job and a manual trigger, or across different application instances), a race condition can occur. Both operations might identify the same enrolment as 'missing' and attempt to create a report for it. The second INSERT operation for the same enrolment_id then fails due to the unique constraint on the _enrolment (which maps to enrolment_id) field.

Solution:
To resolve this, ignore_conflicts=True has been added to the bulk_create call within the create_missing method. This modification instructs the database to silently skip any INSERT operations that would result in a unique constraint violation. This ensures that if an EnrolmentReport for a given enrolment_id already exists, no error is raised, and the existing record is preserved, effectively handling the race condition without requiring complex locking mechanisms or ON CONFLICT clauses.

Fixes KULTUS-API-7

Summary by CodeRabbit

• Bug Fixes
  • Improved report generation reliability by skipping duplicate or conflicting entries when creating missing enrolment reports.
  • Reduced the chance of failures during bulk creation, helping reports complete more consistently.

[azure-pipelines]

KULTUS-API branch is deployed to platta: https://kultus-pr517.api.dev.hel.ninja 🚀🚀🚀

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[voneiden]

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 97af8331-38d0-43bc-8ba3-476c0c4762f8

📥 Commits

Reviewing files that changed from the base of the PR and between cd3d76b and 5a9d33d.

📒 Files selected for processing (1)

• reports/models.py

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📝 Walkthrough

Walkthrough

EnrolmentReportManager.create_missing in reports/models.py is updated to pass ignore_conflicts=True to bulk_create, so duplicate or conflicting rows are silently skipped instead of raising a database error.

Changes

EnrolmentReport conflict handling

Layer / File(s)	Summary
bulk_create ignore_conflicts flag reports/models.py	ignore_conflicts=True is added to the bulk_create call in create_missing, causing conflicting rows to be silently skipped during bulk insertion.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~2 minutes

Poem

A bunny once tripped on a duplicate row,
And crashed through the warren with errors in tow.
Now ignore_conflicts hops gently past,
No more loud exceptions, peace found at last!
🐇✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main fix: preventing duplicate EnrolmentReport creation during sync.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

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🧪 Generate unit tests (beta)

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• Commit unit tests in branch seer/fix/enrolment-report-integrity-error

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[azure-pipelines]

KULTUS-API branch is deployed to platta: https://kultus-pr517.api.dev.hel.ninja 🚀🚀🚀

[mhieta]

LGTM