From 6cf7d92904e2eec21958fa26256c7d169db2af30 Mon Sep 17 00:00:00 2001
From: Vasiliy Tolstov <v.tolstov@unistack.org>
Date: Tue, 22 Feb 2022 14:17:16 +0300
Subject: [PATCH] fix panic

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>
---
 zerolog.go      | 13 ++++++-------
 zerolog_test.go |  9 ++++++++-
 2 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/zerolog.go b/zerolog.go
index c164b09..02b3c81 100644
--- a/zerolog.go
+++ b/zerolog.go
@@ -126,7 +126,11 @@ func (l *zeroLogger) Init(opts ...logger.Option) error {
 	if l.opts.Fields != nil {
 		data := make(map[string]interface{}, len(l.opts.Fields)/2)
 		for i := 0; i < len(l.opts.Fields); i += 2 {
-			data[l.opts.Fields[i].(string)] = l.opts.Fields[i+1]
+			fld, ok := l.opts.Fields[i].(string)
+			if !ok {
+				return fmt.Errorf("field type invalid %T not string", l.opts.Fields[i])
+			}
+			data[fld] = l.opts.Fields[i+1]
 		}
 		l.zLog = l.zLog.With().Fields(data).Logger()
 	}
@@ -140,12 +144,7 @@ func (l *zeroLogger) Init(opts ...logger.Option) error {
 }
 
 func (l *zeroLogger) Fields(fields ...interface{}) logger.Logger {
-	data := make(map[string]interface{}, len(fields)/2)
-	for i := 0; i < len(fields); i += 2 {
-		data[fields[i].(string)] = fields[i+1]
-	}
-	l.zLog = l.zLog.With().Fields(data).Logger()
-	return l
+	return l.Clone(logger.WithFields(fields...))
 }
 
 func (l *zeroLogger) V(level logger.Level) bool {
diff --git a/zerolog_test.go b/zerolog_test.go
index b897709..6b295c7 100644
--- a/zerolog_test.go
+++ b/zerolog_test.go
@@ -19,10 +19,17 @@ func TestFields(t *testing.T) {
 	if err := l.Init(); err != nil {
 		t.Fatal(err)
 	}
-	l.Fields("key", "val").Infof(ctx, "message")
+	nl := l.Fields("key", "val")
+	nl.Infof(ctx, "message")
 	if !bytes.Contains(buf.Bytes(), []byte(`"key":"val"`)) {
 		t.Fatalf("logger fields not works, buf contains: %s", buf.Bytes())
 	}
+	buf.Reset()
+	mnl := l.Fields(map[string]interface{}{"key": "val"})
+	mnl.Infof(ctx, "message")
+	if bytes.Contains(buf.Bytes(), []byte(`"key":"val"`)) {
+		t.Fatalf("logger fields not works, buf contains: %s", buf.Bytes())
+	}
 }
 
 func TestOutput(t *testing.T) {