fix: Unmarshal struct decoding when passing in a pointer to a pointer

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

.github/workflows/ci.yaml

@@ -24,7 +24,7 @@ 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'
 
@@ -52,7 +52,7 @@ 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: ${{ matrix.go }}
 
@@ -73,7 +73,7 @@ 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'
 

.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@c0d1daa7f7e14667747d73a7dbbe8c074bc8bfe2 # v2.22.9
       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@c0d1daa7f7e14667747d73a7dbbe8c074bc8bfe2 # v2.22.9
 
     # 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@c0d1daa7f7e14667747d73a7dbbe8c074bc8bfe2 # v2.22.9
 

viper.go

@@ -1127,6 +1127,13 @@ func (v *Viper) Unmarshal(rawVal any, opts ...DecoderConfigOption) error {
 func (v *Viper) decodeStructKeys(input any, opts ...DecoderConfigOption) ([]string, error) {
 	var structKeyMap map[string]any
 
+	rv := reflect.ValueOf(input)
+	for rv.Kind() == reflect.Ptr {
+		rv = reflect.Indirect(rv)
+	}
+
+	input = rv.Interface()
+
 	err := decode(input, defaultDecoderConfig(&structKeyMap, opts...))
 	if err != nil {
 		return nil, err
@@ -1179,7 +1186,14 @@ func (v *Viper) UnmarshalExact(rawVal any, opts ...DecoderConfigOption) error {
 	config := defaultDecoderConfig(rawVal, opts...)
 	config.ErrorUnused = true
 
-	return decode(v.AllSettings(), config)
+	// TODO: make this optional?
+	structKeys, err := v.decodeStructKeys(rawVal, opts...)
+	if err != nil {
+		return err
+	}
+
+	// TODO: struct keys should be enough?
+	return decode(v.getSettings(append(v.AllKeys(), structKeys...)), config)
 }
 
 // BindPFlags binds a full flag set to the configuration, using each flag's long

viper_test.go

@@ -1052,6 +1052,74 @@ 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 TestUnmarshalIndirection(t *testing.T) {
+	v := New()
+
+	v.Set("foo", "bar")
+
+	type config struct {
+		Foo string
+	}
+
+	var C config
+
+	CC := &C
+	CCC := &CC
+
+	err := v.Unmarshal(&CCC)
+	require.NoError(t, err)
+
+	assert.Equal(t, config{"bar"}, C)
+}
+
+func TestUnmarshalInterface(t *testing.T) {
+	v := New()
+
+	v.Set("foo", "bar")
+
+	type someInterface interface {
+		Foo() string
+	}
+
+	type config struct {
+		Foo   string
+		Fooer someInterface
+	}
+
+	var C config
+
+	err := v.Unmarshal(&C)
+	require.NoError(t, err)
+
+	assert.Equal(t, config{Foo: "bar"}, C)
 }
 
 func TestBindPFlags(t *testing.T) {