Fix nil pointer on watch function

.gitignore

@@ -21,9 +21,4 @@ _testmain.go
 
 *.exe
 *.test
-*.bench
-
-.vscode
-
-# exclude dependencies in the `/vendor` folder
-vendor
+*.bench

viper.go

@@ -30,7 +30,6 @@ import (
 	"path/filepath"
 	"reflect"
 	"strings"
-	"sync"
 	"time"
 
 	yaml "gopkg.in/yaml.v2"
@@ -277,73 +276,50 @@ func (v *Viper) OnConfigChange(run func(in fsnotify.Event)) {
 }
 
 func WatchConfig() { v.WatchConfig() }
-
 func (v *Viper) WatchConfig() {
-	initWG := sync.WaitGroup{}
-	initWG.Add(1)
 	go func() {
 		watcher, err := fsnotify.NewWatcher()
 		if err != nil {
 			log.Fatal(err)
 		}
 		defer watcher.Close()
+
 		// we have to watch the entire directory to pick up renames/atomic saves in a cross-platform way
 		filename, err := v.getConfigFile()
 		if err != nil {
-			log.Printf("error: %v\n", err)
+			log.Println("error:", err)
 			return
 		}
 
 		configFile := filepath.Clean(filename)
 		configDir, _ := filepath.Split(configFile)
-		realConfigFile, _ := filepath.EvalSymlinks(filename)
 
-		eventsWG := sync.WaitGroup{}
-		eventsWG.Add(1)
+		done := make(chan bool)
 		go func() {
 			for {
 				select {
-				case event, ok := <-watcher.Events:
-					if !ok { // 'Events' channel is closed
-						eventsWG.Done()
-						return
-					}
-					currentConfigFile, _ := filepath.EvalSymlinks(filename)
-					// we only care about the config file with the following cases:
-					// 1 - if the config file was modified or created
-					// 2 - if the real path to the config file changed (eg: k8s ConfigMap replacement)
-					const writeOrCreateMask = fsnotify.Write | fsnotify.Create
-					if (filepath.Clean(event.Name) == configFile &&
-						event.Op&writeOrCreateMask != 0) ||
-						(currentConfigFile != "" && currentConfigFile != realConfigFile) {
-						realConfigFile = currentConfigFile
-						err := v.ReadInConfig()
-						if err != nil {
-							log.Printf("error reading config file: %v\n", err)
+				case event := <-watcher.Events:
+					// we only care about the config file
+					if filepath.Clean(event.Name) == configFile {
+						if event.Op&fsnotify.Write == fsnotify.Write || event.Op&fsnotify.Create == fsnotify.Create {
+							err := v.ReadInConfig()
+							if err != nil {
+								log.Println("error:", err)
+							}
+							if v.onConfigChange != nil {
+								v.onConfigChange(event)
+							}
 						}
-						if v.onConfigChange != nil {
-							v.onConfigChange(event)
-						}
-					} else if filepath.Clean(event.Name) == configFile &&
-						event.Op&fsnotify.Remove&fsnotify.Remove != 0 {
-						eventsWG.Done()
-						return
 					}
-
-				case err, ok := <-watcher.Errors:
-					if ok { // 'Errors' channel is not closed
-						log.Printf("watcher error: %v\n", err)
-					}
-					eventsWG.Done()
-					return
+				case err := <-watcher.Errors:
+					log.Println("error:", err)
 				}
 			}
 		}()
+
 		watcher.Add(configDir)
-		initWG.Done()   // done initalizing the watch in this go routine, so the parent routine can move on...
-		eventsWG.Wait() // now, wait for event loop to end in this go-routine...
+		<-done
 	}()
-	initWG.Wait() // make sure that the go routine above fully ended before returning
 }
 
 // SetConfigFile explicitly defines the path, name and extension of the config file.

viper_test.go

@@ -12,24 +12,19 @@ import (
 	"io"
 	"io/ioutil"
 	"os"
-	"os/exec"
 	"path"
 	"reflect"
-	"runtime"
 	"sort"
 	"strings"
-	"sync"
 	"testing"
 	"time"
 
-	"github.com/fsnotify/fsnotify"
 	"github.com/mitchellh/mapstructure"
 	"github.com/spf13/afero"
 	"github.com/spf13/cast"
 
 	"github.com/spf13/pflag"
 	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
 )
 
 var yamlExample = []byte(`Hacker: true
@@ -1411,107 +1406,6 @@ func doTestCaseInsensitive(t *testing.T, typ, config string) {
 
 }
 
-func newViperWithConfigFile(t *testing.T) (*Viper, string, func()) {
-	watchDir, err := ioutil.TempDir("", "")
-	require.Nil(t, err)
-	configFile := path.Join(watchDir, "config.yaml")
-	err = ioutil.WriteFile(configFile, []byte("foo: bar\n"), 0640)
-	require.Nil(t, err)
-	cleanup := func() {
-		os.RemoveAll(watchDir)
-	}
-	v := New()
-	v.SetConfigFile(configFile)
-	err = v.ReadInConfig()
-	require.Nil(t, err)
-	require.Equal(t, "bar", v.Get("foo"))
-	return v, configFile, cleanup
-}
-
-func newViperWithSymlinkedConfigFile(t *testing.T) (*Viper, string, string, func()) {
-	watchDir, err := ioutil.TempDir("", "")
-	require.Nil(t, err)
-	dataDir1 := path.Join(watchDir, "data1")
-	err = os.Mkdir(dataDir1, 0777)
-	require.Nil(t, err)
-	realConfigFile := path.Join(dataDir1, "config.yaml")
-	t.Logf("Real config file location: %s\n", realConfigFile)
-	err = ioutil.WriteFile(realConfigFile, []byte("foo: bar\n"), 0640)
-	require.Nil(t, err)
-	cleanup := func() {
-		os.RemoveAll(watchDir)
-	}
-	// now, symlink the tm `data1` dir to `data` in the baseDir
-	os.Symlink(dataDir1, path.Join(watchDir, "data"))
-	// and link the `<watchdir>/datadir1/config.yaml` to `<watchdir>/config.yaml`
-	configFile := path.Join(watchDir, "config.yaml")
-	os.Symlink(path.Join(watchDir, "data", "config.yaml"), configFile)
-	t.Logf("Config file location: %s\n", path.Join(watchDir, "config.yaml"))
-	// init Viper
-	v := New()
-	v.SetConfigFile(configFile)
-	err = v.ReadInConfig()
-	require.Nil(t, err)
-	require.Equal(t, "bar", v.Get("foo"))
-	return v, watchDir, configFile, cleanup
-}
-
-func TestWatchFile(t *testing.T) {
-
-	t.Run("file content changed", func(t *testing.T) {
-		// given a `config.yaml` file being watched
-		v, configFile, cleanup := newViperWithConfigFile(t)
-		defer cleanup()
-		_, err := os.Stat(configFile)
-		require.NoError(t, err)
-		t.Logf("test config file: %s\n", configFile)
-		wg := sync.WaitGroup{}
-		wg.Add(1)
-		v.OnConfigChange(func(in fsnotify.Event) {
-			t.Logf("config file changed")
-			wg.Done()
-		})
-		v.WatchConfig()
-		// when overwriting the file and waiting for the custom change notification handler to be triggered
-		err = ioutil.WriteFile(configFile, []byte("foo: baz\n"), 0640)
-		wg.Wait()
-		// then the config value should have changed
-		require.Nil(t, err)
-		assert.Equal(t, "baz", v.Get("foo"))
-	})
-
-	t.Run("link to real file changed (à la Kubernetes)", func(t *testing.T) {
-		// skip if not executed on Linux
-		if runtime.GOOS != "linux" {
-			t.Skipf("Skipping test as symlink replacements don't work on non-linux environment...")
-		}
-		v, watchDir, _, _ := newViperWithSymlinkedConfigFile(t)
-		// defer cleanup()
-		wg := sync.WaitGroup{}
-		v.WatchConfig()
-		v.OnConfigChange(func(in fsnotify.Event) {
-			t.Logf("config file changed")
-			wg.Done()
-		})
-		wg.Add(1)
-		// when link to another `config.yaml` file
-		dataDir2 := path.Join(watchDir, "data2")
-		err := os.Mkdir(dataDir2, 0777)
-		require.Nil(t, err)
-		configFile2 := path.Join(dataDir2, "config.yaml")
-		err = ioutil.WriteFile(configFile2, []byte("foo: baz\n"), 0640)
-		require.Nil(t, err)
-		// change the symlink using the `ln -sfn` command
-		err = exec.Command("ln", "-sfn", dataDir2, path.Join(watchDir, "data")).Run()
-		require.Nil(t, err)
-		wg.Wait()
-		// then
-		require.Nil(t, err)
-		assert.Equal(t, "baz", v.Get("foo"))
-	})
-
-}
-
 func BenchmarkGetBool(b *testing.B) {
 	key := "BenchmarkGetBool"
 	v = New()