fix: log panic when use nil error or stringer with Field method (#4130)

core/logx/logs.go

@@ -6,6 +6,7 @@ import (
 	"log"
 	"os"
 	"path"
+	"reflect"
 	"runtime/debug"
 	"sync"
 	"sync/atomic"
@@ -153,11 +154,11 @@ func Errorw(msg string, fields ...LogField) {
 func Field(key string, value any) LogField {
 	switch val := value.(type) {
 	case error:
-		return LogField{Key: key, Value: val.Error()}
+		return LogField{Key: key, Value: encodeError(val)}
 	case []error:
 		var errs []string
 		for _, err := range val {
-			errs = append(errs, err.Error())
+			errs = append(errs, encodeError(err))
 		}
 		return LogField{Key: key, Value: errs}
 	case time.Duration:
@@ -175,11 +176,11 @@ func Field(key string, value any) LogField {
 		}
 		return LogField{Key: key, Value: times}
 	case fmt.Stringer:
-		return LogField{Key: key, Value: val.String()}
+		return LogField{Key: key, Value: encodeStringer(val)}
 	case []fmt.Stringer:
 		var strs []string
 		for _, str := range val {
-			strs = append(strs, str.String())
+			strs = append(strs, encodeStringer(str))
 		}
 		return LogField{Key: key, Value: strs}
 	default:
@@ -414,6 +415,32 @@ func createOutput(path string) (io.WriteCloser, error) {
 	return NewLogger(path, rule, options.gzipEnabled)
 }
 
+func encodeError(err error) (ret string) {
+	return encodeWithRecover(err, func() string {
+		return err.Error()
+	})
+}
+
+func encodeStringer(v fmt.Stringer) (ret string) {
+	return encodeWithRecover(v, func() string {
+		return v.String()
+	})
+}
+
+func encodeWithRecover(arg any, fn func() string) (ret string) {
+	defer func() {
+		if err := recover(); err != nil {
+			if v := reflect.ValueOf(arg); v.Kind() == reflect.Ptr && v.IsNil() {
+				ret = nilAngleString
+			} else {
+				panic(err)
+			}
+		}
+	}()
+
+	return fn()
+}
+
 func getWriter() Writer {
 	w := writer.Load()
 	if w == nil {

core/logx/logs_test.go

@@ -348,6 +348,25 @@ func TestStructedLogInfow(t *testing.T) {
 	})
 }
 
+func TestStructedLogInfowNil(t *testing.T) {
+	w := new(mockWriter)
+	old := writer.Swap(w)
+	defer writer.Store(old)
+
+	assert.Panics(t, func() {
+		var ps panicStringer
+		Infow("test", Field("bb", ps))
+	})
+	assert.NotPanics(t, func() {
+		var s *string
+		Infow("test", Field("bb", s))
+		var d *nilStringer
+		Infow("test", Field("bb", d))
+		var e *nilError
+		Errorw("test", Field("bb", e))
+	})
+}
+
 func TestStructedLogInfoConsoleAny(t *testing.T) {
 	w := new(mockWriter)
 	old := writer.Swap(w)
@@ -859,3 +878,25 @@ func validateFields(t *testing.T, content string, fields map[string]any) {
 		}
 	}
 }
+
+type nilError struct {
+	Name string
+}
+
+func (e *nilError) Error() string {
+	return e.Name
+}
+
+type nilStringer struct {
+	Name string
+}
+
+func (s *nilStringer) String() string {
+	return s.Name
+}
+
+type panicStringer struct{}
+
+func (s panicStringer) String() string {
+	panic("panic")
+}

core/logx/vars.go

@@ -48,6 +48,7 @@ const (
 	levelDebug  = "debug"
 
 	backupFileDelimiter = "-"
+	nilAngleString      = "<nil>"
 	flags               = 0x0
 )
 

core/logx/writer.go

@@ -277,6 +277,20 @@ func combineGlobalFields(fields []LogField) []LogField {
 	return ret
 }
 
+func marshalJson(t interface{}) ([]byte, error) {
+	var buf bytes.Buffer
+	encoder := json.NewEncoder(&buf)
+	encoder.SetEscapeHTML(false)
+	err := encoder.Encode(t)
+	// go 1.5+ will append a newline to the end of the json string
+	// https://github.com/golang/go/issues/13520
+	if l := buf.Len(); l > 0 && buf.Bytes()[l-1] == '\n' {
+		buf.Truncate(l - 1)
+	}
+
+	return buf.Bytes(), err
+}
+
 func output(writer io.Writer, level string, val any, fields ...LogField) {
 	// only truncate string content, don't know how to truncate the values of other types.
 	if v, ok := val.(string); ok {
@@ -333,7 +347,7 @@ func wrapLevelWithColor(level string) string {
 }
 
 func writeJson(writer io.Writer, info any) {
-	if content, err := json.Marshal(info); err != nil {
+	if content, err := marshalJson(info); err != nil {
 		log.Printf("err: %s\n\n%s", err.Error(), debug.Stack())
 	} else if writer == nil {
 		log.Println(string(content))