[AbbyGavin]

Fixes #470

Displays a more useful message than a broken image link if the image doesn't actually exist. The only way I could get it to appear is if the CWL diagram wasn't parsable. I've added a message for that, but other cases could easily have a message added.

[Copilot]

🟡 Changes recommended

Failed CWL rendering triggers extraction twice in the same request, repeating costly external commands instead of reusing the original generation outcome.

1 open issue

• Avoid rerunning CWL extraction after failed diagram generation · New

What changed in this PR

This PR addresses #470 by showing a warning instead of a broken image when a workflow diagram is unavailable, with a specific message for CWL generation errors.

Changes:

• Adds diagram-error reporting through the workflow model and extractors.
• Displays fallback warnings on the workflow page.
• Adds rendering tests and a malformed CWL fixture.

File	Description
test/​functional/​workflows_controller_test.rb	Tests SVG, non-SVG, and failed-generation displays.
test/​fixtures/​files/​workflows/​rp2/​workflows/​broken_cwl.cwl	Adds malformed CWL input.
test/​factories/​workflows.rb	Adds a workflow factory for diagram failures.
test/​factories/​content_blobs.rb	Adds a content-blob factory using malformed CWL.
lib/​seek/​workflow_extractors/​rolike.rb	Delegates error checks to the applicable extractor.
lib/​seek/​workflow_extractors/​rocrate.rb	Wraps error checks in crate access.
lib/​seek/​workflow_extractors/​cwl.rb	Separates diagram extraction and adds error detection.
lib/​seek/​workflow_extractors/​base.rb	Defines the default diagram-error predicate.
app/​views/​workflows/​show.html.erb	Shows warnings when no diagram is available.
app/​models/​concerns/​workflow_extraction.rb	Exposes the extractor’s error check to the view.

_{Review effort: Balanced}