Summary

Mashlib attempts to PATCH container URLs (ending in /), which JSS correctly rejects with 409. This causes console errors during normal mashlib operation.

Observed Behavior

Console shows repeated errors:

PATCH http://jss:4000/mel/ 409 (Conflict)
followOrCreateLink: Error making link in <http://jss:4000/mel/> to <http://jss:4000/publicTypeIndex.ttl>

Server Response

{"error": "Cannot PATCH containers"}

Analysis

JSS behavior is correct. Per Solid spec, containers cannot be PATCHed directly. The 409 response is appropriate.

Mashlib behavior appears incorrect. It's trying to:

1. PATCH the container /mel/ to add type index links
2. This should instead PATCH the profile document /mel/index.html or /mel/card

Code Location

JSS handler at src/handlers/resource.js:466:

if (isContainer(urlPath)) {
  return reply.code(409).send({ error: 'Cannot PATCH containers' });
}

Impact

• Console noise (multiple 409 errors)
• Type index links may not be created properly
• No data loss (correctly rejected)

Potential Solutions

1. Upstream fix in mashlib/solid-ui - PATCH profile document, not container
2. JSS could return more helpful error - Include suggestion to PATCH profile document instead

Related URLs

• Container: http://jss:4000/mel/
• Profile document: http://jss:4000/mel/index.html
• Type indexes: http://jss:4000/mel/settings/publicTypeIndex

Questions

• Is mashlib expecting the container URL to resolve to a profile document?
• Should JSS content-negotiate container requests to return profile RDF?

Status

• Issue identified
• Root cause in mashlib needs investigation
• Determine if JSS should handle this differently