lib/go-tc/tovalidate/validate.go

package tovalidate

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

// http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import (
	"errors"
	"fmt"
	"strings"
)

// ToErrors converts a map of strings to errors into an array of errors.
//
// This is accomplished using `fmt.Errorf("'%v' %v", key, value)` where 'key'
// is the map key and 'value' is the error value to which it points - this
// means that error identity is NOT preserved. For example:
//
//	errMap := map[string]error{
//	    "sql.ErrNoRows": sql.ErrNoRows,
//	}
//	errs := ToErrors(errMap)
//	if errors.Is(errs[0], sql.ErrNoRows) {
//	    fmt.Println("true")
//	} else {
//	    fmt.Println("false")
//	}
//
// ... will output 'false'.
func ToErrors(err map[string]error) []error {
	vErrors := []error{}
	for key, value := range err {
		if value != nil {
			errMsg := fmt.Errorf("'%v' %w", key, value)
			vErrors = append(vErrors, errMsg)
		}
	}
	return vErrors
}

// ToError converts a map of strings to errors into a single error.
//
// Because multiple errors are collapsed, errors cannot be wrapped and therefore
// error identity cannot be preserved.
func ToError(err map[string]error) error {
	if len(err) == 0 {
		return nil
	}
	var b strings.Builder
	for key, value := range err {
		if value != nil {
			b.WriteRune('\'')
			b.WriteString(key)
			b.WriteString("' ")
			b.WriteString(value.Error())
			b.WriteString(", ")
		}
	}
	msg := strings.TrimSuffix(b.String(), ", ")
	if msg == "" {
		return nil
	}
	return errors.New(msg)
}