fix: add back weak string slice hook

Signed-off-by: Mark Sagi-Kazar <mark.sagikazar@gmail.com>

.github/workflows/ci.yaml

@@ -24,9 +24,9 @@ jobs:
         uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
 
       - name: Set up Go
-        uses: actions/setup-go@93397bea11091df50f3d7e59dc26a7711a8bcfbe # v4.1.0
+        uses: actions/setup-go@0c52d547c9bc32b1aa3301fd7a9cb496313a4491 # v5.0.0
         with:
-          go-version: '1.21'
+          go-version: "1.21"
 
       - name: Build
         run: go build .
@@ -44,15 +44,15 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
-        go: ['1.19', '1.20', '1.21']
+        go: ["1.19", "1.20", "1.21"]
-        tags: ['', 'finder']
+        tags: ["", "finder", "viper_bind_struct"]
 
     steps:
       - name: Checkout repository
         uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
 
       - name: Set up Go
-        uses: actions/setup-go@93397bea11091df50f3d7e59dc26a7711a8bcfbe # v4.1.0
+        uses: actions/setup-go@0c52d547c9bc32b1aa3301fd7a9cb496313a4491 # v5.0.0
         with:
           go-version: ${{ matrix.go }}
 
@@ -73,9 +73,9 @@ jobs:
         uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
 
       - name: Set up Go
-        uses: actions/setup-go@93397bea11091df50f3d7e59dc26a7711a8bcfbe # v4.1.0
+        uses: actions/setup-go@0c52d547c9bc32b1aa3301fd7a9cb496313a4491 # v5.0.0
         with:
-          go-version: '1.21'
+          go-version: "1.21"
 
       - name: Lint
         uses: golangci/golangci-lint-action@3a919529898de77ec3da873e3063ca4b10e7f5cc # v3.7.0

.github/workflows/codeql-analysis.yaml

@@ -43,7 +43,7 @@ jobs:
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@407ffafae6a767df3e0230c3df91b6443ae8df75 # v2.22.8
+      uses: github/codeql-action/init@b374143c1149a9115d881581d29b8390bbcbb59c # v3.22.11
       with:
         languages: ${{ matrix.language }}
         # If you wish to specify custom queries, you can do so here or in a config file.
@@ -54,7 +54,7 @@ jobs:
     # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
     # If this step fails, then you should remove it and run the build manually (see below)
     - name: Autobuild
-      uses: github/codeql-action/autobuild@407ffafae6a767df3e0230c3df91b6443ae8df75 # v2.22.8
+      uses: github/codeql-action/autobuild@b374143c1149a9115d881581d29b8390bbcbb59c # v3.22.11
 
     # ℹ️ Command-line programs to run using the OS shell.
     # 📚 https://git.io/JvXDl
@@ -68,5 +68,5 @@ jobs:
     #   make release
 
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@407ffafae6a767df3e0230c3df91b6443ae8df75 # v2.22.8
+      uses: github/codeql-action/analyze@b374143c1149a9115d881581d29b8390bbcbb59c # v3.22.11
 

README.md

@@ -802,7 +802,7 @@ if err != nil {
 }
 ```
 
-Viper uses [github.com/mitchellh/mapstructure](https://github.com/mitchellh/mapstructure) under the hood for unmarshaling values which uses `mapstructure` tags by default.
+Viper uses [github.com/go-viper/mapstructure](https://github.com/go-viper/mapstructure) under the hood for unmarshaling values which uses `mapstructure` tags by default.
 
 ### Decoding custom formats
 

go.mod

@@ -4,10 +4,10 @@ go 1.18
 
 require (
 	github.com/fsnotify/fsnotify v1.7.0
+	github.com/go-viper/mapstructure/v2 v2.0.0-alpha.1
 	github.com/hashicorp/hcl v1.0.0
 	github.com/magiconair/properties v1.8.7
-	github.com/mitchellh/mapstructure v1.5.0
+	github.com/pelletier/go-toml/v2 v2.1.1
-	github.com/pelletier/go-toml/v2 v2.1.0
 	github.com/sagikazarmark/crypt v0.17.0
 	github.com/sagikazarmark/locafero v0.4.0
 	github.com/sagikazarmark/slog-shim v0.1.0
@@ -49,6 +49,7 @@ require (
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.17 // indirect
 	github.com/mitchellh/go-homedir v1.1.0 // indirect
+	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
 	github.com/nats-io/nats.go v1.31.0 // indirect

go.sum

@@ -58,6 +58,8 @@ github.com/go-kit/kit v0.9.0/go.mod h1:xBxKIO96dXMWWy0MnWVtmwkA9/13aqxPnvrjFYMA2
 github.com/go-logfmt/logfmt v0.3.0/go.mod h1:Qt1PoO58o5twSAckw1HlFXLmHsOX5/0LbT9GBnD5lWE=
 github.com/go-logfmt/logfmt v0.4.0/go.mod h1:3RMwSq7FuexP4Kalkev3ejPJsZTpXXBr9+V4qmtdjCk=
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
+github.com/go-viper/mapstructure/v2 v2.0.0-alpha.1 h1:TQcrn6Wq+sKGkpyPvppOz99zsMBaUOKXq6HSv655U1c=
+github.com/go-viper/mapstructure/v2 v2.0.0-alpha.1/go.mod h1:oJDH3BJKyqBA2TXFhDsKDGDTlndYOZ6rGS0BRZIxGhM=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
 github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=
@@ -197,8 +199,8 @@ github.com/nats-io/nuid v1.0.1/go.mod h1:19wcPz3Ph3q0Jbyiqsd0kePYG7A95tJPxeL+1OS
 github.com/pascaldekloe/goe v0.0.0-20180627143212-57f6aae5913c/go.mod h1:lzWF7FIEvWOWxwDKqyGYQf6ZUaNfKdP144TG7ZOy1lc=
 github.com/pascaldekloe/goe v0.1.0 h1:cBOtyMzM9HTpWjXfbbunk26uA6nG3a8n06Wieeh0MwY=
 github.com/pascaldekloe/goe v0.1.0/go.mod h1:lzWF7FIEvWOWxwDKqyGYQf6ZUaNfKdP144TG7ZOy1lc=
-github.com/pelletier/go-toml/v2 v2.1.0 h1:FnwAJ4oYMvbT/34k9zzHuZNrhlz48GB3/s6at6/MHO4=
+github.com/pelletier/go-toml/v2 v2.1.1 h1:LWAJwfNvjQZCFIDKWYQaM62NcYeYViCmWIwmOStowAI=
-github.com/pelletier/go-toml/v2 v2.1.0/go.mod h1:tJU2Z3ZkXwnxa4DPO899bsyIoywizdUvyaeZurnPPDc=
+github.com/pelletier/go-toml/v2 v2.1.1/go.mod h1:tJU2Z3ZkXwnxa4DPO899bsyIoywizdUvyaeZurnPPDc=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=

internal/features/bind_struct.go

@@ -0,0 +1,5 @@
+//go:build viper_bind_struct
+
+package features
+
+const BindStruct = true

internal/features/bind_struct_default.go

@@ -0,0 +1,5 @@
+//go:build !viper_bind_struct
+
+package features
+
+const BindStruct = false

viper.go

@@ -34,7 +34,7 @@ import (
 	"time"
 
 	"github.com/fsnotify/fsnotify"
-	"github.com/mitchellh/mapstructure"
+	"github.com/go-viper/mapstructure/v2"
 	slog "github.com/sagikazarmark/slog-shim"
 	"github.com/spf13/afero"
 	"github.com/spf13/cast"
@@ -48,6 +48,7 @@ import (
 	"github.com/spf13/viper/internal/encoding/json"
 	"github.com/spf13/viper/internal/encoding/toml"
 	"github.com/spf13/viper/internal/encoding/yaml"
+	"github.com/spf13/viper/internal/features"
 )
 
 // ConfigMarshalError happens when failing to marshal the configuration.
@@ -1114,14 +1115,20 @@ func Unmarshal(rawVal any, opts ...DecoderConfigOption) error {
 }
 
 func (v *Viper) Unmarshal(rawVal any, opts ...DecoderConfigOption) error {
-	// TODO: make this optional?
+	keys := v.AllKeys()
-	structKeys, err := v.decodeStructKeys(rawVal, opts...)
+
-	if err != nil {
+	if features.BindStruct {
-		return err
+		// TODO: make this optional?
+		structKeys, err := v.decodeStructKeys(rawVal, opts...)
+		if err != nil {
+			return err
+		}
+
+		keys = append(keys, structKeys...)
 	}
 
 	// TODO: struct keys should be enough?
-	return decode(v.getSettings(append(v.AllKeys(), structKeys...)), defaultDecoderConfig(rawVal, opts...))
+	return decode(v.getSettings(keys), defaultDecoderConfig(rawVal, opts...))
 }
 
 func (v *Viper) decodeStructKeys(input any, opts ...DecoderConfigOption) ([]string, error) {
@@ -1151,7 +1158,8 @@ func defaultDecoderConfig(output any, opts ...DecoderConfigOption) *mapstructure
 		WeaklyTypedInput: true,
 		DecodeHook: mapstructure.ComposeDecodeHookFunc(
 			mapstructure.StringToTimeDurationHookFunc(),
-			mapstructure.StringToSliceHookFunc(","),
+			// mapstructure.StringToSliceHookFunc(","),
+			stringToWeakSliceHookFunc(","),
 		),
 	}
 	for _, opt := range opts {
@@ -1160,6 +1168,28 @@ func defaultDecoderConfig(output any, opts ...DecoderConfigOption) *mapstructure
 	return c
 }
 
+// As of mapstructure v2.0.0 StringToSliceHookFunc checks if the return type is a string slice.
+// This function removes that check.
+// TODO: implement a function that checks if the value can be converted to the return type and use it instead.
+func stringToWeakSliceHookFunc(sep string) mapstructure.DecodeHookFunc {
+	return func(
+		f reflect.Type,
+		t reflect.Type,
+		data interface{},
+	) (interface{}, error) {
+		if f.Kind() != reflect.String || t.Kind() != reflect.Slice {
+			return data, nil
+		}
+
+		raw := data.(string)
+		if raw == "" {
+			return []string{}, nil
+		}
+
+		return strings.Split(raw, sep), nil
+	}
+}
+
 // decode is a wrapper around mapstructure.Decode that mimics the WeakDecode functionality.
 func decode(input any, config *mapstructure.DecoderConfig) error {
 	decoder, err := mapstructure.NewDecoder(config)
@@ -1179,7 +1209,20 @@ func (v *Viper) UnmarshalExact(rawVal any, opts ...DecoderConfigOption) error {
 	config := defaultDecoderConfig(rawVal, opts...)
 	config.ErrorUnused = true
 
-	return decode(v.AllSettings(), config)
+	keys := v.AllKeys()
+
+	if features.BindStruct {
+		// TODO: make this optional?
+		structKeys, err := v.decodeStructKeys(rawVal, opts...)
+		if err != nil {
+			return err
+		}
+
+		keys = append(keys, structKeys...)
+	}
+
+	// TODO: struct keys should be enough?
+	return decode(v.getSettings(keys), config)
 }
 
 // BindPFlags binds a full flag set to the configuration, using each flag's long

viper_test.go

@@ -21,13 +21,14 @@ import (
 	"time"
 
 	"github.com/fsnotify/fsnotify"
-	"github.com/mitchellh/mapstructure"
+	"github.com/go-viper/mapstructure/v2"
 	"github.com/spf13/afero"
 	"github.com/spf13/cast"
 	"github.com/spf13/pflag"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
+	"github.com/spf13/viper/internal/features"
 	"github.com/spf13/viper/internal/testutil"
 )
 
@@ -956,6 +957,10 @@ func TestUnmarshalWithDecoderOptions(t *testing.T) {
 }
 
 func TestUnmarshalWithAutomaticEnv(t *testing.T) {
+	if !features.BindStruct {
+		t.Skip("binding struct is not enabled")
+	}
+
 	t.Setenv("PORT", "1313")
 	t.Setenv("NAME", "Steve")
 	t.Setenv("DURATION", "1s1ms")
@@ -1052,6 +1057,32 @@ func TestUnmarshalWithAutomaticEnv(t *testing.T) {
 
 		assert.Error(t, err, "expected viper.Unmarshal to return error due to unset field 'FLAG'")
 	})
+
+	t.Run("Exact", func(t *testing.T) {
+		var config Configuration
+
+		v.Set("port", 1234)
+		if err := v.UnmarshalExact(&config); err != nil {
+			t.Fatalf("unable to decode into struct, %v", err)
+		}
+
+		assert.Equal(
+			t,
+			Configuration{
+				Name:     "Steve",
+				Port:     1234,
+				Duration: time.Second + time.Millisecond,
+				Modes:    []int{1, 2, 3},
+				Authentication: AuthConfig{
+					Secret: "42",
+				},
+				Storage: StorageConfig{
+					Size: 4096,
+				},
+			},
+			config,
+		)
+	})
 }
 
 func TestBindPFlags(t *testing.T) {