add tests for ordered Multiple/Collection issue#737

[bourgeoa]

Ordered Multiple/Collection field does not serialize as proper RDF list issue #737
Should be resolved with rdflib v2.3.8

[Copilot]

Pull request overview

Adds a workaround in src/widgets/forms.js for issue #737, where ordered ui:Multiple fields were producing duplicate RDF list heads after a document re-fetch. createListIfNecessary now recovers an existing Collection from the store before allocating a new one, saveListThenRefresh rebuilds the Collection from the current list.elements and removes any stale list-head statements via statementsMatching + removeStatement to avoid rdflib's element-content indexing pitfall, and refresh re-binds list to the store's current list head. New Jest tests cover these paths, and __mocks__/rdflib.ts gains a Fetcher.putBack stub so the tests can exercise the save flow.

Changes:

• Patch createListIfNecessary, saveListThenRefresh, and refresh in forms.js to prevent duplicate ordered-list heads after re-fetch.
• Add test/unit/widgets/forms/multiple.test.ts covering recovery, refresh, add, and dedup-on-save paths.
• Mock Fetcher.putBack in __mocks__/rdflib.ts; add lit-html to dependencies in package.json (apparently unrelated to the stated PR purpose).

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 5 comments.

File	Description
src/widgets/forms.js	Recover existing list head, rebuild Collection before save, sync list in refresh.
test/unit/widgets/forms/multiple.test.ts	New unit tests for ordered Multiple-field list-head behavior.
mocks/rdflib.ts	Adds putBack stub on Fetcher so the new tests can run.
package.json	Adds lit-html as a direct dependency (unrelated to the issue).

Comments suppressed due to low confidence (2)

src/widgets/forms.js:537

• saveListThenRefresh now unconditionally removes the existing list-head triple(s) and adds a freshly-constructed Collection on every call, even when no element changed and there were no duplicate heads. If kb.fetcher.putBack(dataDoc) subsequently fails, the in-memory store has already been mutated (old statement removed, new statement added), leaving the local store out of sync with the remote document. Consider either (a) only rebuilding when duplicates are detected or list.elements has actually changed, or (b) restoring the previous statement on putBack failure.

This issue also appears on line 544 of the same file.

    const currentElements = list.elements.slice()
    const oldStatements = reverse
      ? kb.statementsMatching(null, property, subject, dataDoc)
      : kb.statementsMatching(subject, property, null, dataDoc)
    oldStatements.forEach(st => kb.removeStatement(st))
    list = new $rdf.Collection(currentElements)
    if (reverse) {
      kb.add(list, property, subject, dataDoc)
    } else {
      kb.add(subject, property, list, dataDoc)
    }

    try {
      await kb.fetcher.putBack(dataDoc)
    } catch (err) {
      box.appendChild(
        errorMessageBlock(dom, 'Error trying to put back a list: ' + err)
      )
      return
    }

src/widgets/forms.js:548

• In refresh(), kb.the(subject, property, null, dataDoc) is used to fetch the single list head. When the duplicate-head bug scenario is in effect (two Collection statements for the same subject/property), kb.the in rdflib emits a warning and arbitrarily picks one — meaning the displayed list may flip between the two collections depending on internal ordering, and the user may see stale or unexpected content prior to the next save. Consider using kb.each(...) and explicitly picking/merging, or detecting and consolidating duplicates here as well rather than only in saveListThenRefresh.

      const li = reverse ? kb.the(null, property, subject, dataDoc) : kb.the(subject, property, null, dataDoc)
      if (li) {
        list = li // Keep list in sync with the store after any external document reload
      }
      vals = li ? li.elements : []

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.