What causes "presenter not found for ${_class}" in hcengineering/platform?

Add view.mixin.CollectionPresenter with a presenter resource to the target class definition

presenter not found for ${_class}

Error message

presenter not found for ${_class}

What it means

When resolving the presenter for an association's end class, the code looks for a classHierarchyMixin implementing view.mixin.CollectionPresenter with a defined `presenter`. If the class hierarchy provides no presenter mixin, it logs and throws.

Source

Thrown at plugins/view-resources/src/utils.ts:712

        key: key.key,
        sortingKey: '',
        _class,
        label: getEmbeddedLabel(name + ' › ' + subFieldParts.join('.')),
        presenter,
        props: key.props,
        displayProps: key.displayProps,
        collectionAttr: false,
        isLookup: true
      }
    }
  }

  const presenterMixin = hierarchy.classHierarchyMixin(_class, view.mixin.CollectionPresenter)
  if (presenterMixin?.presenter === undefined) {
    console.error(
      `object presenter not found for class=${_class}, mixin=${view.mixin.ObjectPresenter}, preserve key ${JSON.stringify(key)}`
    )
    throw new Error('presenter not found for ' + _class)
  }
  const presenter = await getResource(presenterMixin.presenter)

  return {
    key: key.key,
    sortingKey: '',
    _class,
    label: getEmbeddedLabel(name),
    presenter,
    props: key.props,
    displayProps: key.displayProps,
    collectionAttr: false,
    isLookup: true
  }
}

export async function deleteObject (client: TxOperations, object: Doc): Promise<void> {
  const currentAcc = getCurrentAccount()

View on GitHub (pinned to 63e28dc964)

Solutions

Add view.mixin.CollectionPresenter with a presenter resource to the target class definition
Register the presenter resource so getResource(presenterMixin.presenter) resolves
Check the mixin is applied via classHierarchyMixin on all subclasses of the displayed class

Example fix

// before
class MyDoc extends Doc {} // no presenter mixin
// after
@Model('my::MyDoc', Doc)
export class MyDoc extends Doc {}
hierarchy.addMixin(MyDoc, view.mixin.CollectionPresenter, { presenter: myPresenterResource })

Defensive patterns

Strategy: validation

Validate before calling

const hierarchy = client.getHierarchy()
const mixin = hierarchy.classHierarchyMixin(targetClass, view.mixin.CollectionPresenter)
if (mixin?.presenter === undefined) {
  throw new Error(`register CollectionPresenter for ${targetClass} first`)
}

Type guard

function hasCollectionPresenter(h: Hierarchy, _class: Ref<Class<Doc>>): boolean {
  return h.classHierarchyMixin(_class, view.mixin.CollectionPresenter)?.presenter !== undefined
}

Try / catch

try {
  return await model(client, _class, keys)
} catch (err) {
  if (String(err.message).startsWith('presenter not found')) {
    console.error('add view.mixin.CollectionPresenter to', _class)
    return []
  }
  throw err
}

Prevention

Register CollectionPresenter mixin whenever you introduce a new domain class
Lint/verify class definitions include presenter mixins
Test view building for every custom class in CI

When it happens

Trigger: Building a model for an $associations relation whose target class does not register a CollectionPresenter mixin (or the mixin exists but presenter is undefined).

Common situations: Custom domain class added without declaring view.mixin.CollectionPresenter in its class definition; typo in mixin resource id; class hierarchy not loaded for the target class.

Related errors

AI-assisted analysis of hcengineering/platform@63e28dc964 (2026-08-29). Data as JSON: /api/errors/bd81d4ea2673a857. Report an issue: GitHub.