context   string // additional error context
	pos       errPos
	atChar    byte
	readerErr error // underlying reader error, if any
}

// ReaderErr returns the underlying error.
func (e DecoderError) ReaderErr() error { return e.readerErr }

// Error returns a string representation of the error.
func (e DecoderError) Error() string {
	loc := fmt.Sprintf("%s [%d,%d]", quoteChar(e.atChar), e.pos[0], e.pos[1])

type ChecksumMismatch struct {
	Want string
	Got  string
}

func (e ChecksumMismatch) Error() string {
	return "Bad checksum: Want " + e.Want + " does not match calculated " + e.Got
}

// IsChecksumMismatch matches if 'err' is hash.ChecksumMismatch
func IsChecksumMismatch(err error) bool {
	var herr ChecksumMismatch
	return errors.As(err, &herr)

	return errors.Is(err, syscall.EXDEV)
}

// Check if given error corresponds to too many open files
func isSysErrTooManyFiles(err error) bool {
	return errors.Is(err, syscall.ENFILE) || errors.Is(err, syscall.EMFILE)
}

func osIsNotExist(err error) bool {
	return errors.Is(err, os.ErrNotExist)
}

func osIsPermission(err error) bool {

// error returned when temporary account is not found
var errNoSuchTempAccount = errors.New("Specified temporary account does not exist")

// error returned in IAM subsystem when an account doesn't exist.
var errNoSuchAccount = errors.New("Specified account does not exist")

// error returned in IAM subsystem when groups doesn't exist.

func Errorf(format string, a ...interface{}) error {
	e := fmt.Errorf(format, a...)
	ee := Error{}
	ee.msg = e.Error()
	ee.cause = errors.Unwrap(e)
	return ee
}

// Unwrap the internal error.
func (e Error) Unwrap() error { return e.cause }

// Error 'error' compatible method.
func (e Error) Error() string {
	if e.msg == "" {
		return "crypto: cause <nil>"
	}
	return e.msg
}

package s3select

import "strings"

// SelectError - represents s3 select error specified in
// https://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectSELECTContent.html#RESTObjectSELECTContent-responses-special-errors.
type SelectError interface {
	Cause() error
	ErrorCode() string
	ErrorMessage() string
	HTTPStatusCode() int
	Error() string
}

type s3Error struct {
	code       string
	message    string

package nodeagent

import (
	"errors"
	"fmt"
)

var ErrPartialAdd = errors.New("partial add error")

type PartialAddError struct {
	inner error
}

func (e *PartialAddError) Error() string {
	return fmt.Sprintf("%s: %v", ErrPartialAdd.Error(), e.inner)
}

func (e *PartialAddError) Unwrap() []error {
	return []error{ErrPartialAdd, e.inner}
}

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package csv

import "errors"

type s3Error struct {
	code       string
	message    string
	statusCode int
	cause      error
}

func (err *s3Error) Cause() error {
	return err.cause
}

func (err *s3Error) ErrorCode() string {
	return err.code
}

func (err *s3Error) ErrorMessage() string {

package grid

import (
	"errors"
	"fmt"
)

var (
	// ErrUnknownHandler is returned when an unknown handler is requested.
	ErrUnknownHandler = errors.New("unknown mux handler")

	// ErrHandlerAlreadyExists is returned when a handler is already registered.
	ErrHandlerAlreadyExists = errors.New("mux handler already exists")

**FastAPI** uses it so that, if you use a Pydantic model in `response_model`, and your data has an error, you will see the error in your log.

But the client/user will not see it. Instead, the client will receive an "Internal Server Error" with an HTTP status code `500`.