chore: replace interface{} with any (Go 1.18+ alias) and fix reflect type checks

- modules/* and internal/lib/formatting/format.go: switch to any alias
- modules/terraform/var-file.go: replace reflect.TypeOf string check with type assertion

Linear: OSS-3296

Author: james00012

internal/lib/formatting/format.go

@@ -10,7 +10,7 @@ import (
 
 // FormatBackendConfigAsArgs formats backend configuration as Terraform CLI args.
 // Example: {"bucket": "my-bucket"} -> ["-backend-config=bucket=my-bucket"]
-func FormatBackendConfigAsArgs(vars map[string]interface{}) []string {
+func FormatBackendConfigAsArgs(vars map[string]any) []string {
 	return formatTerraformArgs(vars, "-backend-config", false, true)
 }
 
@@ -25,7 +25,7 @@ func FormatPluginDirAsArgs(pluginDir string) []string {
 }
 
 // formatTerraformArgs formats vars as CLI args with the given prefix.
-func formatTerraformArgs(vars map[string]interface{}, prefix string, useSpaceAsSeparator bool, omitNil bool) []string {
+func formatTerraformArgs(vars map[string]any, prefix string, useSpaceAsSeparator bool, omitNil bool) []string {
 	var args []string
 
 	for key, value := range vars {
@@ -49,7 +49,7 @@ func formatTerraformArgs(vars map[string]interface{}, prefix string, useSpaceAsS
 
 // ToHCLString converts Go values to HCL-formatted strings for Terraform CLI arguments.
 // Handles primitives, slices, and maps. Example: []int{1,2,3} -> "[1, 2, 3]"
-func ToHCLString(value interface{}, isNested bool) string {
+func ToHCLString(value any, isNested bool) string {
 	if slice, isSlice := tryToConvertToGenericSlice(value); isSlice {
 		return sliceToHclString(slice)
 	} else if m, isMap := tryToConvertToGenericMap(value); isMap {
@@ -59,14 +59,14 @@ func ToHCLString(value interface{}, isNested bool) string {
 	}
 }
 
-// tryToConvertToGenericSlice converts any slice type to []interface{} using reflection.
-func tryToConvertToGenericSlice(value interface{}) ([]interface{}, bool) {
+// tryToConvertToGenericSlice converts any slice type to []any using reflection.
+func tryToConvertToGenericSlice(value any) ([]any, bool) {
 	reflectValue := reflect.ValueOf(value)
 	if reflectValue.Kind() != reflect.Slice {
-		return []interface{}{}, false
+		return []any{}, false
 	}
 
-	genericSlice := make([]interface{}, reflectValue.Len())
+	genericSlice := make([]any, reflectValue.Len())
 
 	for i := 0; i < reflectValue.Len(); i++ {
 		genericSlice[i] = reflectValue.Index(i).Interface()
@@ -75,19 +75,19 @@ func tryToConvertToGenericSlice(value interface{}) ([]interface{}, bool) {
 	return genericSlice, true
 }
 
-// tryToConvertToGenericMap converts any map[string]T to map[string]interface{} using reflection.
-func tryToConvertToGenericMap(value interface{}) (map[string]interface{}, bool) {
+// tryToConvertToGenericMap converts any map[string]T to map[string]any using reflection.
+func tryToConvertToGenericMap(value any) (map[string]any, bool) {
 	reflectValue := reflect.ValueOf(value)
 	if reflectValue.Kind() != reflect.Map {
-		return map[string]interface{}{}, false
+		return map[string]any{}, false
 	}
 
 	reflectType := reflect.TypeOf(value)
 	if reflectType.Key().Kind() != reflect.String {
-		return map[string]interface{}{}, false
+		return map[string]any{}, false
 	}
 
-	genericMap := make(map[string]interface{}, reflectValue.Len())
+	genericMap := make(map[string]any, reflectValue.Len())
 
 	mapKeys := reflectValue.MapKeys()
 	for _, key := range mapKeys {
@@ -97,7 +97,7 @@ func tryToConvertToGenericMap(value interface{}) (map[string]interface{}, bool)
 	return genericMap, true
 }
 
-func sliceToHclString(slice []interface{}) string {
+func sliceToHclString(slice []any) string {
 	hclValues := make([]string, 0, len(slice))
 
 	for _, value := range slice {
@@ -108,7 +108,7 @@ func sliceToHclString(slice []interface{}) string {
 	return fmt.Sprintf("[%s]", strings.Join(hclValues, ", "))
 }
 
-func mapToHclString(m map[string]interface{}) string {
+func mapToHclString(m map[string]any) string {
 	keyValuePairs := make([]string, 0, len(m))
 
 	for key, value := range m {
@@ -119,7 +119,7 @@ func mapToHclString(m map[string]interface{}) string {
 	return fmt.Sprintf("{%s}", strings.Join(keyValuePairs, ", "))
 }
 
-func primitiveToHclString(value interface{}, isNested bool) string {
+func primitiveToHclString(value any, isNested bool) string {
 	if value == nil {
 		return "null"
 	}

internal/lib/formatting/format_test.go

@@ -12,27 +12,27 @@ func TestFormatBackendConfigAsArgs(t *testing.T) {
 
 	tests := []struct {
 		name   string
-		input  map[string]interface{}
+		input  map[string]any
 		expect []string
 	}{
 		{
 			name:   "empty config",
-			input:  map[string]interface{}{},
+			input:  map[string]any{},
 			expect: []string{},
 		},
 		{
 			name:   "string value",
-			input:  map[string]interface{}{"bucket": "my-bucket"},
+			input:  map[string]any{"bucket": "my-bucket"},
 			expect: []string{"-backend-config=bucket=my-bucket"},
 		},
 		{
 			name:   "nil value omitted",
-			input:  map[string]interface{}{"key": nil},
+			input:  map[string]any{"key": nil},
 			expect: []string{"-backend-config=key"},
 		},
 		{
 			name:   "multiple values",
-			input:  map[string]interface{}{"region": "us-east-1", "bucket": "state"},
+			input:  map[string]any{"region": "us-east-1", "bucket": "state"},
 			expect: []string{"-backend-config=bucket=state", "-backend-config=region=us-east-1"},
 		},
 	}
@@ -82,7 +82,7 @@ func TestToHclString(t *testing.T) {
 
 	tests := []struct {
 		name   string
-		input  interface{}
+		input  any
 		expect string
 	}{
 		{"nil", nil, "null"},
@@ -93,7 +93,7 @@ func TestToHclString(t *testing.T) {
 		{"list of strings", []string{"a", "b"}, `["a", "b"]`},
 		{"list of ints", []int{1, 2, 3}, "[1, 2, 3]"},
 		{"map", map[string]string{"key": "value"}, `{"key" = "value"}`},
-		{"nested list", []interface{}{[]int{1, 2}}, "[[1, 2]]"},
+		{"nested list", []any{[]int{1, 2}}, "[[1, 2]]"},
 	}
 
 	for _, tt := range tests {

modules/aws/lambda.go

@@ -50,7 +50,7 @@ type LambdaOptions struct {
 	InvocationType *InvocationTypeOption
 
 	// Lambda function input; will be converted to JSON.
-	Payload interface{}
+	Payload any
 }
 
 // LambdaOutput contains the output from InvokeFunctionWithParams().  The
@@ -68,7 +68,7 @@ type LambdaOutput struct {
 
 // InvokeFunctionContextE invokes a lambda function.
 // The ctx parameter supports cancellation and timeouts.
-func InvokeFunctionContextE(t testing.TestingT, ctx context.Context, region, functionName string, payload interface{}) ([]byte, error) {
+func InvokeFunctionContextE(t testing.TestingT, ctx context.Context, region, functionName string, payload any) ([]byte, error) {
 	lambdaClient, err := NewLambdaClientContextE(t, ctx, region)
 	if err != nil {
 		return nil, err
@@ -102,7 +102,7 @@ func InvokeFunctionContextE(t testing.TestingT, ctx context.Context, region, fun
 // InvokeFunctionContext invokes a lambda function.
 // This function will fail the test if there is an error.
 // The ctx parameter supports cancellation and timeouts.
-func InvokeFunctionContext(t testing.TestingT, ctx context.Context, region, functionName string, payload interface{}) []byte {
+func InvokeFunctionContext(t testing.TestingT, ctx context.Context, region, functionName string, payload any) []byte {
 	t.Helper()
 	out, err := InvokeFunctionContextE(t, ctx, region, functionName, payload)
 	require.NoError(t, err)
@@ -113,15 +113,15 @@ func InvokeFunctionContext(t testing.TestingT, ctx context.Context, region, func
 // InvokeFunction invokes a lambda function.
 //
 // Deprecated: Use [InvokeFunctionContext] instead.
-func InvokeFunction(t testing.TestingT, region, functionName string, payload interface{}) []byte {
+func InvokeFunction(t testing.TestingT, region, functionName string, payload any) []byte {
 	t.Helper()
 	return InvokeFunctionContext(t, context.Background(), region, functionName, payload)
 }
 
 // InvokeFunctionE invokes a lambda function.
 //
 // Deprecated: Use [InvokeFunctionContextE] instead.
-func InvokeFunctionE(t testing.TestingT, region, functionName string, payload interface{}) ([]byte, error) {
+func InvokeFunctionE(t testing.TestingT, region, functionName string, payload any) ([]byte, error) {
 	return InvokeFunctionContextE(t, context.Background(), region, functionName, payload)
 }
 

modules/helm/template.go

@@ -233,7 +233,7 @@ func UnmarshalK8SYamlsE[T any](t testing.TestingT, yamlData string, destinationO
 }
 
 // UnmarshalK8SYaml is the same as UnmarshalK8SYamlE, but will fail the test if there is an error.
-func UnmarshalK8SYaml(t testing.TestingT, yamlData string, destinationObj interface{}) {
+func UnmarshalK8SYaml(t testing.TestingT, yamlData string, destinationObj any) {
 	require.NoError(t, UnmarshalK8SYamlE(t, yamlData, destinationObj))
 }
 
@@ -244,7 +244,7 @@ func UnmarshalK8SYaml(t testing.TestingT, yamlData string, destinationObj interf
 //	UnmarshalK8SYamlE(t, renderedOutput, &deployment)
 //
 // At the end of this, the deployment variable will be populated.
-func UnmarshalK8SYamlE(t testing.TestingT, yamlData string, destinationObj interface{}) error {
+func UnmarshalK8SYamlE(t testing.TestingT, yamlData string, destinationObj any) error {
 	decoder := goyaml.NewDecoder(strings.NewReader(yamlData))
 
 	// Ensure destinationObj is a pointer
@@ -258,7 +258,7 @@ func UnmarshalK8SYamlE(t testing.TestingT, yamlData string, destinationObj inter
 	// Handle single object or list as root
 	if destElem.Kind() != reflect.Slice {
 		// Decode only the first document
-		var rawYaml interface{}
+		var rawYaml any
 		if err := decoder.Decode(&rawYaml); err != nil {
 			return goerrors.WithStackTrace(err)
 		}
@@ -285,7 +285,7 @@ func UnmarshalK8SYamlE(t testing.TestingT, yamlData string, destinationObj inter
 	sliceVal := slicePtr.Elem()
 
 	for {
-		var rawYaml interface{}
+		var rawYaml any
 		if err := decoder.Decode(&rawYaml); err != nil {
 			if errors.Is(err, io.EOF) {
 				break // No more documents

modules/packer/packer.go

@@ -367,7 +367,7 @@ type packerManifestBuild struct {
 	BuilderType   string                    `json:"builder_type"`
 	ArtifactID    string                    `json:"artifact_id"`
 	PackerRunUUID string                    `json:"packer_run_uuid"`
-	CustomData    map[string]interface{}    `json:"custom_data"`
+	CustomData    map[string]any            `json:"custom_data"`
 	Files         []packerManifestBuildFile `json:"files"`
 	BuildTime     int64                     `json:"build_time"`
 }

modules/ssh/session.go

@@ -114,6 +114,6 @@ func Close(t testing.TestingT, closeable Closeable, ignoreErrors ...string) {
 // interfaceIsNil checks whether the given interface value is nil. A direct nil comparison does not work for interface
 // values that wrap a typed nil pointer, so reflection is used.
 // See https://go.dev/doc/faq#nil_error for details.
-func interfaceIsNil(i interface{}) bool {
+func interfaceIsNil(i any) bool {
 	return i == nil || reflect.ValueOf(i).IsNil()
 }

modules/terraform/var-file.go

@@ -72,12 +72,13 @@ func GetVariableAsMapFromVarFileE(t testing.TestingT, fileName string, key strin
 		return nil, InputFileKeyNotFound{FilePath: fileName, Key: key}
 	}
 
-	if reflect.TypeOf(variable).String() != "map[string]interface {}" {
-		return nil, UnexpectedOutputType{Key: key, ExpectedType: "map[string]interface {}", ActualType: reflect.TypeOf(variable).String()}
+	mapVariable, ok := variable.(map[string]any)
+	if !ok {
+		return nil, UnexpectedOutputType{Key: key, ExpectedType: "map[string]any", ActualType: reflect.TypeOf(variable).String()}
 	}
 
 	resultMap := make(map[string]string)
-	for mapKey, mapVal := range variable.(map[string]any) {
+	for mapKey, mapVal := range mapVariable {
 		resultMap[mapKey] = fmt.Sprintf("%v", mapVal)
 	}
 
@@ -109,12 +110,13 @@ func GetVariableAsListFromVarFileE(t testing.TestingT, fileName string, key stri
 		return nil, InputFileKeyNotFound{FilePath: fileName, Key: key}
 	}
 
-	if reflect.TypeOf(variable).String() != "[]interface {}" {
-		return nil, UnexpectedOutputType{Key: key, ExpectedType: "[]interface {}", ActualType: reflect.TypeOf(variable).String()}
+	listVariable, ok := variable.([]any)
+	if !ok {
+		return nil, UnexpectedOutputType{Key: key, ExpectedType: "[]any", ActualType: reflect.TypeOf(variable).String()}
 	}
 
 	resultArray := []string{}
-	for _, item := range variable.([]any) {
+	for _, item := range listVariable {
 		resultArray = append(resultArray, fmt.Sprintf("%v", item))
 	}
 

modules/terragrunt/json_helpers.go

@@ -161,7 +161,7 @@ func CleanTerragruntJSON(input string) (string, error) {
 	}
 
 	// Parse JSON
-	var jsonObj interface{}
+	var jsonObj any
 	if err := json.Unmarshal([]byte(cleaned), &jsonObj); err != nil {
 		return "", err
 	}

modules/terragrunt/options.go

@@ -71,7 +71,7 @@ type Options struct {
 	Logger *logger.Logger // Logger for command output
 
 	// Complex configuration that requires special formatting (NOT raw command-line args)
-	BackendConfig map[string]interface{} // Backend configuration (formatted specially)
+	BackendConfig map[string]any // Backend configuration (formatted specially)
 
 	// Test framework configuration (NOT passed to tg command line)
 	TerragruntBinary string // The tg binary to use (should be "terragrunt")

modules/terragrunt/render_test.go

@@ -40,7 +40,7 @@ func TestRenderJSON(t *testing.T) {
 		TerragruntBinary: "terragrunt",
 	})
 
-	var parsed map[string]interface{}
+	var parsed map[string]any
 	require.NoError(t, json.Unmarshal([]byte(output), &parsed), "output should be valid JSON")
 	require.Contains(t, parsed, "terraform")
 }