doc.Unmarshal does not play well with json tag

[semolex]

Hello Clover DB team,

I've encountered an issue while integrating Clover DB with the Wails framework. It seems that when using struct tags for JSON unmarshaling alongside Clover's own tags, the unmarshaled struct ends up with default values for certain fields, rather than the values stored in the database.

Environment:

• Clover DB version: v2.0.0-alpha.3
• Wails version: v2.7.1
• Go version: 1.20.6
• Operating System: macOS Sonoma 14.1.1

Steps to Reproduce

1. Create a struct with both json and clover tags.
2. Store a document in Clover DB with non-default values for all fields.
3. Unmarshal the document into the struct using Clover DB's unmarshaling logic.

func (f *WorkersCollection) GetAllWorkers() ([]Worker, error) {
	workerModel := &Worker{}
	docs, err := f.manager.getAll(workerMode) // just a call to db.FindAll(query.NewQuery(collectionName))

	if err != nil {
		return nil, err
	}
	var workers []Worker

	for _, doc := range docs {
		log.Infof("", doc)
		var worker Worker
		err := doc.Unmarshal(&worker)
		if err != nil {
			return nil, NewCustomError(err.Error(), failedToUnmarshal)
		}
		log.Printf("Unmarshalled worker: %+v\n", worker)
		workers = append(workers, worker)
	}

	return workers, nil
}

Expected Behavior

The struct fields should reflect the values stored in the database.

Actual Behavior

Some fields in the struct are set to their default Go values, despite having different values stored in the database.

Example

• Document stored in Clover DB:

{
    "_id": "124b0a50-a6ce-4297-8718-69553f9c4222",
    "is_worker": true,
    "balance_actual": 91,
    "balance_by_account": 100,
    "name": "Test if marshalling works",
    "manager_id": "5560100f-52a3-483d-a8c6-3059397d1197"
}

• Corresponding Go struct:

type Worker struct {
	Id               string `json:"id" clover:"_id"`
	Name             string `json:"name" clover:"name"`
	BalanceActual    int    `json:"balance_actual" clover:"balance_actual"`
	ManagerId        string `json:"manager_id" clover:"manager_id"`
	IsWorker         bool   `json:"is_worker" clover:"is_worker"`
	BalanceByAccount int    `json:"balance_by_account" clover:"balance_by_account"`
}

• Result after unmarshaling (struct):
  {Id:124b0a50-a6ce-4297-8718-69553f9c4222 Name:Test if marshalling works BalanceActual:0 ManagerId:"" BalanceByAccount:0 IsWorker:false}
  I receive this unmarshaled result on frontend (with json-specified fields e.g. snake_case).

Is there is some undocumented way to use both tags or some designed way to specify those fields?
I could definitely use are maps but in a certain way I am using type validations, possible method calls etc.
Thank you for looking into this issue. I am looking forward to your response or guidance on how to address this problem.

[univac490]

I made a local copy of clover/internal/encoding.go and updated createRenameMap as follows:

func createRenameMap(rv reflect.Value) map[string]string {
	renameMap := make(map[string]string)
	for i := 0; i < rv.NumField(); i++ {
		fieldType := rv.Type().Field(i)

		tagStr, found := fieldType.Tag.Lookup("clover")
		if found {
			name, _ := processStructTag(tagStr)
			jsonTagStr, found := fieldType.Tag.Lookup("json")
			if found {
				jsonName, _ := processStructTag(jsonTagStr)
				if jsonName != name {
					renameMap[name] = jsonName
				}
			} else {
				renameMap[name] = fieldType.Name
			}
		}
	}
	return renameMap
}

[univac490]

actually, the json tag should be always be checked, not just when the clover tag is found.

[ostafen]

@semolex: thank you for reporting the issue.

@univac490: could you submit a PR?

[ostafen]

@semolex: please check if still have the issue.
@univac490: thank you very much for fix :=)

[semolex]

@ostafen Thanks. Confirmed. Waiting for a next release