Remove superflous insensitiviseMaps in Unmarshal methods

Fixes #482

.travis.yml

@@ -1,8 +1,12 @@
 go_import_path: github.com/spf13/viper
 
 language: go
+
+env:
+  global:
+  - GO111MODULE="on"
+
 go:
-  - 1.10.x
   - 1.11.x
   - tip
 

README.md

@@ -179,13 +179,14 @@ viper.GetBool("verbose") // true
 ### Working with Environment Variables
 
 Viper has full support for environment variables. This enables 12 factor
-applications out of the box. There are four methods that exist to aid working
+applications out of the box. There are five methods that exist to aid working
 with ENV:
 
  * `AutomaticEnv()`
  * `BindEnv(string...) : error`
  * `SetEnvPrefix(string)`
  * `SetEnvKeyReplacer(string...) *strings.Replacer`
+  * `AllowEmptyEnvVar(bool)`
 
 _When working with ENV variables, it’s important to recognize that Viper
 treats ENV variables as case sensitive._
@@ -217,6 +218,10 @@ keys to an extent. This is useful if you want to use `-` or something in your
 `Get()` calls, but want your environmental variables to use `_` delimiters. An
 example of using it can be found in `viper_test.go`.
 
+By default empty environment variables are considered unset and will fall back to
+the next configuration source. To treat empty environment variables as set, use
+the `AllowEmptyEnv` method.
+
 #### Env example
 
 ```go

go.mod

@@ -1,16 +1,24 @@
 module github.com/spf13/viper
 
 require (
+	github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6 // indirect
+	github.com/coreos/etcd v3.3.10+incompatible // indirect
+	github.com/coreos/go-etcd v2.0.0+incompatible // indirect
+	github.com/coreos/go-semver v0.2.0 // indirect
 	github.com/fsnotify/fsnotify v1.4.7
 	github.com/hashicorp/hcl v1.0.0
 	github.com/magiconair/properties v1.8.0
-	github.com/mitchellh/mapstructure v1.0.0
+	github.com/mitchellh/mapstructure v1.1.2
 	github.com/pelletier/go-toml v1.2.0
 	github.com/spf13/afero v1.1.2
-	github.com/spf13/cast v1.2.0
+	github.com/spf13/cast v1.3.0
 	github.com/spf13/jwalterweatherman v1.0.0
-	github.com/spf13/pflag v1.0.2
-	golang.org/x/sys v0.0.0-20180906133057-8cf3aee42992 // indirect
+	github.com/spf13/pflag v1.0.3
+	github.com/stretchr/testify v1.2.2
+	github.com/ugorji/go/codec v0.0.0-20181204163529-d75b2dcb6bc8 // indirect
+	github.com/xordataexchange/crypt v0.0.3-0.20170626215501-b2862e3d0a77
+	golang.org/x/crypto v0.0.0-20181203042331-505ab145d0a9 // indirect
+	golang.org/x/sys v0.0.0-20181205085412-a5c9d58dba9a // indirect
 	golang.org/x/text v0.3.0 // indirect
-	gopkg.in/yaml.v2 v2.2.1
+	gopkg.in/yaml.v2 v2.2.2
 )

go.sum

@@ -1,3 +1,7 @@
+github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6/go.mod h1:grANhF5doyWs3UAsr3K4I6qtAmlQcZDesFNEHPZAzj8=
+github.com/coreos/etcd v3.3.10+incompatible/go.mod h1:uF7uidLiAD3TWHmW31ZFd/JWoc32PjwdhPthX9715RE=
+github.com/coreos/go-etcd v2.0.0+incompatible/go.mod h1:Jez6KQU2B/sWsbdaef3ED8NzMklzPG4d5KIOhIy30Tk=
+github.com/coreos/go-semver v0.2.0/go.mod h1:nnelYz7RCh+5ahJtPPxZlU+153eP4D4r3EedlOD2RNk=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fsnotify/fsnotify v1.4.7 h1:IXs+QLmnXW2CcXuY+8Mzv/fWEsPGWxqefPtCP5CnV9I=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
@@ -5,22 +9,27 @@ github.com/hashicorp/hcl v1.0.0 h1:0Anlzjpi4vEasTeNFn2mLJgTSwt0+6sfsiTG8qcWGx4=
 github.com/hashicorp/hcl v1.0.0/go.mod h1:E5yfLk+7swimpb2L/Alb/PJmXilQ/rhwaUYs4T20WEQ=
 github.com/magiconair/properties v1.8.0 h1:LLgXmsheXeRoUOBOjtwPQCWIYqM/LU1ayDtDePerRcY=
 github.com/magiconair/properties v1.8.0/go.mod h1:PppfXfuXeibc/6YijjN8zIbojt8czPbwD3XqdrwzmxQ=
-github.com/mitchellh/mapstructure v1.0.0 h1:vVpGvMXJPqSDh2VYHF7gsfQj8Ncx+Xw5Y1KHeTRY+7I=
-github.com/mitchellh/mapstructure v1.0.0/go.mod h1:FVVH3fgwuzCH5S8UJGiWEs2h04kUh9fWfEaFds41c1Y=
+github.com/mitchellh/mapstructure v1.1.2 h1:fmNYVwqnSfB9mZU6OS2O6GsXM+wcskZDuKQzvN1EDeE=
+github.com/mitchellh/mapstructure v1.1.2/go.mod h1:FVVH3fgwuzCH5S8UJGiWEs2h04kUh9fWfEaFds41c1Y=
 github.com/pelletier/go-toml v1.2.0 h1:T5zMGML61Wp+FlcbWjRDT7yAxhJNAiPPLOFECq181zc=
 github.com/pelletier/go-toml v1.2.0/go.mod h1:5z9KED0ma1S8pY6P1sdut58dfprrGBbd/94hg7ilaic=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/spf13/afero v1.1.2 h1:m8/z1t7/fwjysjQRYbP0RD+bUIF/8tJwPdEZsI83ACI=
 github.com/spf13/afero v1.1.2/go.mod h1:j4pytiNVoe2o6bmDsKpLACNPDBIoEAkihy7loJ1B0CQ=
-github.com/spf13/cast v1.2.0 h1:HHl1DSRbEQN2i8tJmtS6ViPyHx35+p51amrdsiTCrkg=
-github.com/spf13/cast v1.2.0/go.mod h1:r2rcYCSwa1IExKTDiTfzaxqT2FNHs8hODu4LnUfgKEg=
+github.com/spf13/cast v1.3.0 h1:oget//CVOEoFewqQxwr0Ej5yjygnqGkvggSE/gB35Q8=
+github.com/spf13/cast v1.3.0/go.mod h1:Qx5cxh0v+4UWYiBimWS+eyWzqEqokIECu5etghLkUJE=
 github.com/spf13/jwalterweatherman v1.0.0 h1:XHEdyB+EcvlqZamSM4ZOMGlc93t6AcsBEu9Gc1vn7yk=
 github.com/spf13/jwalterweatherman v1.0.0/go.mod h1:cQK4TGJAtQXfYWX+Ddv3mKDzgVb68N+wFjFa4jdeBTo=
-github.com/spf13/pflag v1.0.2 h1:Fy0orTDgHdbnzHcsOgfCN4LtHf0ec3wwtiwJqwvf3Gc=
-github.com/spf13/pflag v1.0.2/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
-golang.org/x/sys v0.0.0-20180906133057-8cf3aee42992 h1:BH3eQWeGbwRU2+wxxuuPOdFBmaiBH81O8BugSjHeTFg=
-golang.org/x/sys v0.0.0-20180906133057-8cf3aee42992/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+github.com/spf13/pflag v1.0.3 h1:zPAT6CGy6wXeQ7NtTnaTerfKOsV6V6F8agHXFiazDkg=
+github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+github.com/ugorji/go/codec v0.0.0-20181204163529-d75b2dcb6bc8/go.mod h1:VFNgLljTbGfSG7qAOspJ7OScBnGdDN/yBr0sguwnwf0=
+github.com/xordataexchange/crypt v0.0.3-0.20170626215501-b2862e3d0a77/go.mod h1:aYKd//L2LvnjZzWKhF00oedf4jCCReLcmhLdhm1A27Q=
+golang.org/x/crypto v0.0.0-20181203042331-505ab145d0a9/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
+golang.org/x/sys v0.0.0-20181205085412-a5c9d58dba9a h1:1n5lsVfiQW3yfsRGu98756EH1YthsFqr/5mxHduZW2A=
+golang.org/x/sys v0.0.0-20181205085412-a5c9d58dba9a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v2 v2.2.1 h1:mUhvW9EsL+naU5Q3cakzfE91YhliOondGd6ZrsDBHQE=
-gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

viper.go

@@ -187,6 +187,7 @@ type Viper struct {
 
 	automaticEnvApplied bool
 	envKeyReplacer      *strings.Replacer
+	allowEmptyEnv       bool
 
 	config         map[string]interface{}
 	override       map[string]interface{}
@@ -373,6 +374,14 @@ func (v *Viper) mergeWithEnvPrefix(in string) string {
 	return strings.ToUpper(in)
 }
 
+// AllowEmptyEnv tells Viper to consider set,
+// but empty environment variables as valid values instead of falling back.
+// For backward compatibility reasons this is false by default.
+func AllowEmptyEnv(allowEmptyEnv bool) { v.AllowEmptyEnv(allowEmptyEnv) }
+func (v *Viper) AllowEmptyEnv(allowEmptyEnv bool) {
+	v.allowEmptyEnv = allowEmptyEnv
+}
+
 // TODO: should getEnv logic be moved into find(). Can generalize the use of
 // rewriting keys many things, Ex: Get('someKey') -> some_key
 // (camel case to snake case for JSON keys perhaps)
@@ -380,11 +389,14 @@ func (v *Viper) mergeWithEnvPrefix(in string) string {
 // getEnv is a wrapper around os.Getenv which replaces characters in the original
 // key. This allows env vars which have different keys than the config object
 // keys.
-func (v *Viper) getEnv(key string) string {
+func (v *Viper) getEnv(key string) (string, bool) {
 	if v.envKeyReplacer != nil {
 		key = v.envKeyReplacer.Replace(key)
 	}
-	return os.Getenv(key)
+
+	val, ok := os.LookupEnv(key)
+
+	return val, ok && (v.allowEmptyEnv || val != "")
 }
 
 // ConfigFileUsed returns the file used to populate the config registry.
@@ -611,10 +623,9 @@ func (v *Viper) isPathShadowedInFlatMap(path []string, mi interface{}) string {
 //       "foo.bar.baz" in a lower-priority map
 func (v *Viper) isPathShadowedInAutoEnv(path []string) string {
 	var parentKey string
-	var val string
 	for i := 1; i < len(path); i++ {
 		parentKey = strings.Join(path[0:i], v.keyDelim)
-		if val = v.getEnv(v.mergeWithEnvPrefix(parentKey)); val != "" {
+		if _, ok := v.getEnv(v.mergeWithEnvPrefix(parentKey)); ok {
 			return parentKey
 		}
 	}
@@ -800,8 +811,6 @@ func (v *Viper) UnmarshalKey(key string, rawVal interface{}, opts ...DecoderConf
 		return err
 	}
 
-	v.insensitiviseMaps()
-
 	return nil
 }
 
@@ -817,8 +826,6 @@ func (v *Viper) Unmarshal(rawVal interface{}, opts ...DecoderConfigOption) error
 		return err
 	}
 
-	v.insensitiviseMaps()
-
 	return nil
 }
 
@@ -861,8 +868,6 @@ func (v *Viper) UnmarshalExact(rawVal interface{}) error {
 		return err
 	}
 
-	v.insensitiviseMaps()
-
 	return nil
 }
 
@@ -993,7 +998,7 @@ func (v *Viper) find(lcaseKey string) interface{} {
 	if v.automaticEnvApplied {
 		// even if it hasn't been registered, if automaticEnv is used,
 		// check any Get request
-		if val = v.getEnv(v.mergeWithEnvPrefix(lcaseKey)); val != "" {
+		if val, ok := v.getEnv(v.mergeWithEnvPrefix(lcaseKey)); ok {
 			return val
 		}
 		if nested && v.isPathShadowedInAutoEnv(path) != "" {
@@ -1002,7 +1007,7 @@ func (v *Viper) find(lcaseKey string) interface{} {
 	}
 	envkey, exists := v.env[lcaseKey]
 	if exists {
-		if val = v.getEnv(envkey); val != "" {
+		if val, ok := v.getEnv(envkey); ok {
 			return val
 		}
 	}
@@ -1248,13 +1253,21 @@ func (v *Viper) ReadConfig(in io.Reader) error {
 // MergeConfig merges a new configuration with an existing config.
 func MergeConfig(in io.Reader) error { return v.MergeConfig(in) }
 func (v *Viper) MergeConfig(in io.Reader) error {
-	if v.config == nil {
-		v.config = make(map[string]interface{})
-	}
 	cfg := make(map[string]interface{})
 	if err := v.unmarshalReader(in, cfg); err != nil {
 		return err
 	}
+	return v.MergeConfigMap(cfg)
+}
+
+// MergeConfigMap merges the configuration from the map given with an existing config.
+// Note that the map given may be modified.
+func MergeConfigMap(cfg map[string]interface{}) error { return v.MergeConfigMap(cfg) }
+func (v *Viper) MergeConfigMap(cfg map[string]interface{}) error {
+	if v.config == nil {
+		v.config = make(map[string]interface{})
+	}
+	insensitiviseMap(cfg)
 	mergeMaps(cfg, v.config, nil)
 	return nil
 }
@@ -1560,13 +1573,6 @@ func (v *Viper) WatchRemoteConfigOnChannel() error {
 	return v.watchKeyValueConfigOnChannel()
 }
 
-func (v *Viper) insensitiviseMaps() {
-	insensitiviseMap(v.config)
-	insensitiviseMap(v.defaults)
-	insensitiviseMap(v.override)
-	insensitiviseMap(v.kvstore)
-}
-
 // Retrieve the first found remote configuration.
 func (v *Viper) getKeyValueConfig() error {
 	if RemoteConfig == nil {

viper_test.go

@@ -388,6 +388,36 @@ func TestEnv(t *testing.T) {
 
 }
 
+func TestEmptyEnv(t *testing.T) {
+	initJSON()
+
+	BindEnv("type") // Empty environment variable
+	BindEnv("name") // Bound, but not set environment variable
+
+	os.Clearenv()
+
+	os.Setenv("TYPE", "")
+
+	assert.Equal(t, "donut", Get("type"))
+	assert.Equal(t, "Cake", Get("name"))
+}
+
+func TestEmptyEnv_Allowed(t *testing.T) {
+	initJSON()
+
+	AllowEmptyEnv(true)
+
+	BindEnv("type") // Empty environment variable
+	BindEnv("name") // Bound, but not set environment variable
+
+	os.Clearenv()
+
+	os.Setenv("TYPE", "")
+
+	assert.Equal(t, "", Get("type"))
+	assert.Equal(t, "Cake", Get("name"))
+}
+
 func TestEnvPrefix(t *testing.T) {
 	initJSON()
 
@@ -583,24 +613,28 @@ func TestBindPFlags(t *testing.T) {
 }
 
 func TestBindPFlagsStringSlice(t *testing.T) {
-	for _, testValue := range []struct {
+	tests := []struct {
 		Expected []string
 		Value    string
 	}{
-		{[]string{}, ""},
+		{nil, ""},
 		{[]string{"jeden"}, "jeden"},
 		{[]string{"dwa", "trzy"}, "dwa,trzy"},
-		{[]string{"cztery", "piec , szesc"}, "cztery,\"piec , szesc\""}} {
+		{[]string{"cztery", "piec , szesc"}, "cztery,\"piec , szesc\""},
+	}
+
+	v := New() // create independent Viper object
+	defaultVal := []string{"default"}
+	v.SetDefault("stringslice", defaultVal)
+
+	for _, testValue := range tests {
+		flagSet := pflag.NewFlagSet("test", pflag.ContinueOnError)
+		flagSet.StringSlice("stringslice", testValue.Expected, "test")
 
 		for _, changed := range []bool{true, false} {
-			v := New() // create independent Viper object
-			flagSet := pflag.NewFlagSet("test", pflag.ContinueOnError)
-			flagSet.StringSlice("stringslice", testValue.Expected, "test")
-			flagSet.Visit(func(f *pflag.Flag) {
-				if len(testValue.Value) > 0 {
-					f.Value.Set(testValue.Value)
-					f.Changed = changed
-				}
+			flagSet.VisitAll(func(f *pflag.Flag) {
+				f.Value.Set(testValue.Value)
+				f.Changed = changed
 			})
 
 			err := v.BindPFlags(flagSet)
@@ -615,7 +649,11 @@ func TestBindPFlagsStringSlice(t *testing.T) {
 			if err := v.Unmarshal(val); err != nil {
 				t.Fatalf("%+#v cannot unmarshal: %s", testValue.Value, err)
 			}
-			assert.Equal(t, testValue.Expected, val.StringSlice)
+			if changed {
+				assert.Equal(t, testValue.Expected, val.StringSlice)
+			} else {
+				assert.Equal(t, defaultVal, val.StringSlice)
+			}
 		}
 	}
 }
@@ -1192,6 +1230,48 @@ func TestMergeConfigNoMerge(t *testing.T) {
 	}
 }
 
+func TestMergeConfigMap(t *testing.T) {
+	v := New()
+	v.SetConfigType("yml")
+	if err := v.ReadConfig(bytes.NewBuffer(yamlMergeExampleTgt)); err != nil {
+		t.Fatal(err)
+	}
+
+	assert := func(i int) {
+		large := v.GetInt("hello.lagrenum")
+		pop := v.GetInt("hello.pop")
+		if large != 765432101234567 {
+			t.Fatal("Got large num:", large)
+		}
+
+		if pop != i {
+			t.Fatal("Got pop:", pop)
+		}
+	}
+
+	assert(37890)
+
+	update := map[string]interface{}{
+		"Hello": map[string]interface{}{
+			"Pop": 1234,
+		},
+		"World": map[interface{}]interface{}{
+			"Rock": 345,
+		},
+	}
+
+	if err := v.MergeConfigMap(update); err != nil {
+		t.Fatal(err)
+	}
+
+	if rock := v.GetInt("world.rock"); rock != 345 {
+		t.Fatal("Got rock:", rock)
+	}
+
+	assert(1234)
+
+}
+
 func TestUnmarshalingWithAliases(t *testing.T) {
 	v := New()
 	v.SetDefault("ID", 1)
@@ -1457,6 +1537,10 @@ func newViperWithSymlinkedConfigFile(t *testing.T) (*Viper, string, string, func
 }
 
 func TestWatchFile(t *testing.T) {
+	if runtime.GOOS == "linux" {
+		// TODO(bep) FIX ME
+		t.Skip("Skip test on Linux ...")
+	}
 
 	t.Run("file content changed", func(t *testing.T) {
 		// given a `config.yaml` file being watched