From d10c2f9e3c9bf2debfd370a038ca8520f73bd405 Mon Sep 17 00:00:00 2001
From: David Bariod <davidriod@googlemail.com>
Date: Wed, 31 Oct 2018 07:01:35 +0100
Subject: [PATCH] fix panic in text formatter

The panic was caused to a nil pointer access when report
caller was activated with output coloring disabled

Fixes #852
---
 logrus_test.go    | 12 ++++++++++++
 text_formatter.go | 14 +++++++-------
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/logrus_test.go b/logrus_test.go
index f6a0f44..b12d71c 100644
--- a/logrus_test.go
+++ b/logrus_test.go
@@ -702,3 +702,15 @@ func TestLogLevelEnabled(t *testing.T) {
 	assert.Equal(t, true, log.IsLevelEnabled(DebugLevel))
 	assert.Equal(t, true, log.IsLevelEnabled(TraceLevel))
 }
+
+func TestReportCallerOnTextFormatter(t *testing.T) {
+	l := New()
+
+	l.Formatter.(*TextFormatter).ForceColors = true
+	l.Formatter.(*TextFormatter).DisableColors = false
+	l.WithFields(Fields{"func": "func", "file": "file"}).Info("test")
+
+	l.Formatter.(*TextFormatter).ForceColors = false
+	l.Formatter.(*TextFormatter).DisableColors = true
+	l.WithFields(Fields{"func": "func", "file": "file"}).Info("test")
+}
diff --git a/text_formatter.go b/text_formatter.go
index c5f9ca3..49ec92f 100644
--- a/text_formatter.go
+++ b/text_formatter.go
@@ -164,18 +164,18 @@ func (f *TextFormatter) Format(entry *Entry) ([]byte, error) {
 	} else {
 		for _, key := range fixedKeys {
 			var value interface{}
-			switch key {
-			case f.FieldMap.resolve(FieldKeyTime):
+			switch {
+			case key == f.FieldMap.resolve(FieldKeyTime):
 				value = entry.Time.Format(timestampFormat)
-			case f.FieldMap.resolve(FieldKeyLevel):
+			case key == f.FieldMap.resolve(FieldKeyLevel):
 				value = entry.Level.String()
-			case f.FieldMap.resolve(FieldKeyMsg):
+			case key == f.FieldMap.resolve(FieldKeyMsg):
 				value = entry.Message
-			case f.FieldMap.resolve(FieldKeyLogrusError):
+			case key == f.FieldMap.resolve(FieldKeyLogrusError):
 				value = entry.err
-			case f.FieldMap.resolve(FieldKeyFunc):
+			case key == f.FieldMap.resolve(FieldKeyFunc) && entry.HasCaller():
 				value = entry.Caller.Function
-			case f.FieldMap.resolve(FieldKeyFile):
+			case key == f.FieldMap.resolve(FieldKeyFile) && entry.HasCaller():
 				value = fmt.Sprintf("%s:%d", entry.Caller.File, entry.Caller.Line)
 			default:
 				value = entry.Data[key]