hyperledger/fabric · error

unexpected collection type

Error message

unexpected collection type

What it means

While iterating stored collection configs to trim private collection entries, each CollectionConfig payload is type-switched. Only *CollectionConfig_StaticCollectionConfig is supported; any other payload variant causes this error, since the transient store only understands static collections.

Source

Thrown at core/transientstore/store_helper.go:234

func trimPvtCollectionConfigs(configs map[string]*peer.CollectionConfigPackage,
	filter ledger.PvtNsCollFilter,
) (map[string]*peer.CollectionConfigPackage, error) {
	if filter == nil {
		return configs, nil
	}
	result := make(map[string]*peer.CollectionConfigPackage)

	for ns, pkg := range configs {
		result[ns] = &peer.CollectionConfigPackage{}
		for _, colConf := range pkg.GetConfig() {
			switch cconf := colConf.Payload.(type) {
			case *peer.CollectionConfig_StaticCollectionConfig:
				if filter.Has(ns, cconf.StaticCollectionConfig.Name) {
					result[ns].Config = append(result[ns].Config, colConf)
				}
			default:
				return nil, errors.New("unexpected collection type")
			}
		}
	}
	return result, nil
}

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Regenerate/rebuild the transient store data (drop and recreate the store directory)
2. Align Fabric versions/protobuf definitions between peers writing and reading the store
3. Clear stale transient store files after a Fabric upgrade

// before reading the store, confirm all collection configs are static
cconf := rawConf.GetCollectionConfig()
if _, ok := cconf.Payload.(*peer.CollectionConfig_StaticCollectionConfig); !ok {
    return errors.New("unsupported collection config type")
}

func isStaticCollectionConfig(c *peer.CollectionConfig) bool {
    _, ok := c.GetPayload().(*peer.CollectionConfig_StaticCollectionConfig)
    return ok
}

iter, err := store.GetTxPvtRWSetByTxid(txid, filter)
if err != nil {
    if strings.Contains(err.Error(), "unexpected collection type") {
        // data written by incompatible Fabric version: rebuild transient store
    }
    return err
}

When it happens

Trigger: Reading entries from the transient store (via Next()/retrieval with a filter) when a stored collection config message contains a payload type other than StaticCollectionConfig.

Common situations: Protobuf version mismatch between writer and reader (a collection config variant written by a newer/different Fabric version); corrupted transient store data.

Related errors

• collection-name: %s -- cannot unmarshal identity bytes into
• collection-name: %s -- cannot unmarshal identity bytes into
• error unmarshalling
• error encoding output
• error unmarshalling original config

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/3f600884c029b56a. Report an issue: GitHub.