Handle roleless SBOL2 components during import

[simplyshree]

Summary

Fixes an SBOL2 import failure path where SBOLCanvas assumes every ComponentDefinition has at least one role.

Root Cause

SBOLToMx.java checked for circular-backbone components by calling:

cd.getRoles().iterator().next()

Valid SBOL2 ComponentDefinition objects may legally have an empty role set. When a roleless component is imported, such as a generic GenBank misc_feature annotation, this can throw NoSuchElementException and cause Canvas import to fail.

Convert.java then hid unchecked exceptions without messages behind the generic response Export failed, making the real import failure difficult to diagnose.

Changes

• Replaced the first-role lookup with a safe membership check using cd.getRoles().contains(...).
• Added a small errorMessage(Throwable e) helper so conversion failures include the exception class, even when the exception message is null.

Impact

This makes SBOL2 import robust for standards-valid roleless components and also correctly detects circular-backbone roles when a component has multiple roles and the circular role is not first.

Validation

• git diff --check passed.
• Backend Maven tests Passed (Tests run: 67)

Notes

SeqTrainer has a workaround that assigns generic Sequence Ontology role SO:0000110 (sequence_feature) to source features without a narrower mapping, but Canvas should still handle roleless valid SBOL2 components safely.

[simplyshree]

The Azure Static Web Apps check appears to be failing because the repository deployment secret is unavailable in this PR context. if we could either configure the repository token or temporarily set SKIP_DEPLOY_ON_MISSING_SECRETS: true, so the build can complete while deployment is skipped?

[Copilot]

🟢 Approval recommended

The production changes address the import crash path safely and add targeted tests, with only minor non-blocking test maintainability feedback.

Pull request overview

This PR hardens SBOL2 import in the backend by removing an unsafe assumption that every ComponentDefinition has at least one role, and improves conversion error reporting so role-related failures are diagnosable instead of surfacing as a generic “Export failed”.

Changes:

• Fix circular-backbone detection in SBOLToMx by checking role membership with contains(...) instead of reading the “first role”.
• Improve servlet error responses in Convert by including the exception type when the exception message is null.
• Add a regression test covering roleless components and multi-role circular-backbone detection.

File summaries

File	Description
SBOLCanvasBackend/src/test/java/org/sbolcanvas/utils/SBOLToMxRoleHandlingTest.java	Adds regression coverage for roleless component import and circular-backbone detection with multiple roles.
SBOLCanvasBackend/src/main/java/org/sbolcanvas/utils/SBOLToMx.java	Avoids NoSuchElementException by replacing iterator().next() with a safe role membership check.
SBOLCanvasBackend/src/main/java/org/sbolcanvas/servlets/Convert.java	Ensures conversion failures include exception class info when messages are missing.

Review details

• Files reviewed: 3/3 changed files
• Comments generated: 1
• Review effort level: Lite

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[cjmyers]

@travisformayor Please let me us know if you approve this PR

[travisformayor]

Approve. Looks like a good fix on a crash condition, and good to see a unit test added for it as well.