chore: Improve TF schema attribute name generation

go.mod

@@ -19,7 +19,6 @@ require (
 	github.com/hashicorp/terraform-plugin-mux v0.21.0
 	github.com/hashicorp/terraform-plugin-sdk/v2 v2.38.1
 	github.com/hashicorp/terraform-plugin-testing v1.13.3
-	github.com/huandu/xstrings v1.5.0
 	github.com/jarcoal/httpmock v1.4.1
 	github.com/mongodb-forks/digest v1.1.0
 	github.com/mongodb/atlas-sdk-go v1.0.1-0.20251103084024-4a19449c6541

go.sum

@@ -345,8 +345,6 @@ github.com/hashicorp/yamux v0.1.2 h1:XtB8kyFOyHXYVFnwT5C3+Bdo8gArse7j2AQ0DA0Uey8
 github.com/hashicorp/yamux v0.1.2/go.mod h1:C+zze2n6e/7wshOZep2A70/aQU6QBRWJO/G6FT1wIns=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=
 github.com/huandu/xstrings v1.3.2/go.mod h1:y5/lhBue+AyNmUVz9RLU9xbLR0o4KIIExikq4ovT0aE=
-github.com/huandu/xstrings v1.5.0 h1:2ag3IFq9ZDANvthTwTiqSSZLjDc+BedvHPAp5tJy2TI=
-github.com/huandu/xstrings v1.5.0/go.mod h1:y5/lhBue+AyNmUVz9RLU9xbLR0o4KIIExikq4ovT0aE=
 github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 github.com/imdario/mergo v0.3.11/go.mod h1:jmQim1M+e3UYxmgPu/WyfjB3N3VflVyUjjjwH0dnCYA=

internal/common/autogen/stringcase/string_case.go

@@ -1,60 +1,49 @@
 package stringcase
 
 import (
-	"fmt"
 	"regexp"
 	"strings"
 	"unicode"
 	"unicode/utf8"
-
-	"github.com/huandu/xstrings"
-)
-
-var (
-	camelCase             = regexp.MustCompile(`([a-z])[A-Z]`)
-	unsupportedCharacters = regexp.MustCompile(`[^a-zA-Z0-9_]+`)
 )
 
-type SnakeCaseString string
-
-func (snake SnakeCaseString) SnakeCase() string {
-	return string(snake)
-}
-
-func (snake SnakeCaseString) PascalCase() string {
-	return xstrings.ToPascalCase(string(snake))
-}
-
-func (snake SnakeCaseString) CamelCase() string {
-	return xstrings.ToCamelCase(string(snake))
-}
-
-func (snake SnakeCaseString) LowerCaseNoUnderscore() string {
-	return strings.ReplaceAll(string(snake), "_", "")
-}
+var unsupportedCharacters = regexp.MustCompile(`[^a-zA-Z0-9_]+`)
 
-func FromCamelCase(input string) SnakeCaseString {
-	if input == "" {
-		return SnakeCaseString(input)
+// ToSnakeCase Multiple consecutive uppercase letters are treated as part of the same word except for the last one.
+// Example: "MongoDBMajorVersion" -> "mongo_db_major_version"
+func ToSnakeCase(str string) string {
+	if str == "" {
+		return str
 	}
 
-	removedUnsupported := unsupportedCharacters.ReplaceAllString(input, "")
-
-	insertedUnderscores := camelCase.ReplaceAllStringFunc(removedUnsupported, func(s string) string {
-		firstChar := s[0]
-		restOfString := s[1:]
-		return fmt.Sprintf("%c_%s", firstChar, strings.ToLower(restOfString))
-	})
-
-	return SnakeCaseString(strings.ToLower(insertedUnderscores))
-}
+	str = unsupportedCharacters.ReplaceAllString(str, "")
 
-func ToCamelCase(str string) string {
-	return xstrings.ToCamelCase(str)
-}
+	builder := &strings.Builder{}
+	runes := []rune(str)
+	length := len(runes)
+
+	prevIsUpper := unicode.IsUpper(runes[0])
+	builder.WriteRune(unicode.ToLower(runes[0]))
+
+	for i := 1; i < length; i++ {
+		current := runes[i]
+		currentIsUpper := unicode.IsUpper(runes[i])
+
+		// Write an underscore before uppercase letter if:
+		// - Previous char was lowercase, so this is the first uppercase.
+		// - Next char is lowercase, so this is the last uppercase in a sequence.
+		if currentIsUpper {
+			if !prevIsUpper || (i+1 != length && unicode.IsLower(runes[i+1])) {
+				builder.WriteByte('_')
+			}
+			current = unicode.ToLower(current)
+		}
+
+		builder.WriteRune(current)
+		prevIsUpper = currentIsUpper
+	}
 
-func ToSnakeCase(str string) string {
-	return xstrings.ToSnakeCase(str)
+	return builder.String()
 }
 
 func Capitalize(str string) string {

internal/common/autogen/stringcase/string_case_test.go

@@ -46,7 +46,7 @@ func TestCapitalize(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			if actual := stringcase.Capitalize(tt.input); actual != tt.expected {
-				t.Errorf("Capitalize() returned %v, expected %v", actual, tt.expected)
+				t.Errorf("Capitalize(%q) returned %q, expected %q", tt.input, actual, tt.expected)
 			}
 		})
 	}
@@ -92,7 +92,78 @@ func TestUncapitalize(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			if actual := stringcase.Uncapitalize(tt.input); actual != tt.expected {
-				t.Errorf("Uncapitalize() returned %v, expected %v", actual, tt.expected)
+				t.Errorf("Uncapitalize(%q) returned %q, expected %q", tt.input, actual, tt.expected)
+			}
+		})
+	}
+}
+
+func TestToSnakeCase(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "Empty string",
+			input:    "",
+			expected: "",
+		},
+		{
+			name:     "Single letter",
+			input:    "a",
+			expected: "a",
+		},
+		{
+			name:     "Single uppercase letter",
+			input:    "A",
+			expected: "a",
+		},
+		{
+			name:     "Simple camelCase",
+			input:    "camelCase",
+			expected: "camel_case",
+		},
+		{
+			name:     "Simple PascalCase",
+			input:    "PascalCase",
+			expected: "pascal_case",
+		},
+		{
+			name:     "All lowercase",
+			input:    "word",
+			expected: "word",
+		},
+		{
+			name:     "All uppercase",
+			input:    "WORD",
+			expected: "word",
+		},
+		{
+			name:     "Consecutive uppercase at start, middle and end",
+			input:    "THISIsANExampleWORD",
+			expected: "this_is_an_example_word",
+		},
+		{
+			name:     "Numbers do not split words",
+			input:    "Example123Word456WithNUMBERS789",
+			expected: "example123_word456_with_numbers789",
+		},
+		{
+			name:     "Already snake_case",
+			input:    "already_snake_case",
+			expected: "already_snake_case",
+		},
+		{
+			name:     "Unsupported characters are removed",
+			input:    "Example#!Unsup-.ported%&Chars",
+			expected: "example_unsupported_chars",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if actual := stringcase.ToSnakeCase(tt.input); actual != tt.expected {
+				t.Errorf("ToSnakeCase(%q) returned %q, expected %q", tt.input, actual, tt.expected)
 			}
 		})
 	}

internal/serviceapi/clusterapi/resource_test.go

@@ -43,7 +43,7 @@ func TestAccClusterAPI_basic(t *testing.T) {
 				ImportStateVerifyIdentifierAttribute: "name",
 				ImportStateVerifyIgnore: []string{
 					"retain_backups_enabled",   // This field is TF specific and not returned by Atlas, so Import can't fill it in.
-					"mongo_dbmajor_version",    // Risks plan change of 8 --> 8.0 (always normalized to `major.minor`)
+					"mongo_db_major_version",   // Risks plan change of 8 --> 8.0 (always normalized to `major.minor`)
 					"state_name",               // Cluster state can change from IDLE to UPDATING and risks making the test flaky
 					"delete_on_create_timeout", // This field is TF specific and not returned by Atlas, so Import can't fill it in.
 				},

tools/codegen/codespec/api_to_provider_spec_mapper.go

@@ -6,7 +6,6 @@ import (
 	"log"
 	"strings"
 
-	"github.com/mongodb/terraform-provider-mongodbatlas/internal/common/autogen/stringcase"
 	high "github.com/pb33f/libopenapi/datamodel/high/v3"
 	low "github.com/pb33f/libopenapi/datamodel/low/v3"
 	"github.com/pb33f/libopenapi/orderedmap"
@@ -47,12 +46,12 @@ func ToCodeSpecModel(atlasAdminAPISpecFilePath, configPath string, resourceName
 	for name, resourceConfig := range resourceConfigsToIterate {
 		log.Printf("[INFO] Generating resource model: %s", name)
 		// find resource operations, schemas, etc from OAS
-		oasResource, err := getAPISpecResource(&apiSpec.Model, &resourceConfig, stringcase.SnakeCaseString(name))
+		oasResource, err := getAPISpecResource(&apiSpec.Model, &resourceConfig, name)
 		if err != nil {
 			return nil, fmt.Errorf("unable to get APISpecResource schema: %v", err)
 		}
 		// map OAS resource model to CodeSpecModel
-		resource, err := apiSpecResourceToCodeSpecModel(oasResource, &resourceConfig, stringcase.SnakeCaseString(name))
+		resource, err := apiSpecResourceToCodeSpecModel(oasResource, &resourceConfig, name)
 		if err != nil {
 			return nil, fmt.Errorf("unable to map to code spec model for %s: %w", name, err)
 		}
@@ -81,7 +80,7 @@ func validateRequiredOperations(resourceConfigs map[string]config.Resource) erro
 	return nil
 }
 
-func apiSpecResourceToCodeSpecModel(oasResource APISpecResource, resourceConfig *config.Resource, name stringcase.SnakeCaseString) (*Resource, error) {
+func apiSpecResourceToCodeSpecModel(oasResource APISpecResource, resourceConfig *config.Resource, name string) (*Resource, error) {
 	createOp := oasResource.CreateOp
 	updateOp := oasResource.UpdateOp
 	readOp := oasResource.ReadOp
@@ -117,9 +116,10 @@ func apiSpecResourceToCodeSpecModel(oasResource APISpecResource, resourceConfig
 		operations.VersionHeader = getLatestVersionFromAPISpec(readOp)
 	}
 	resource := &Resource{
-		Name:       name,
-		Schema:     schema,
-		Operations: operations,
+		Name:        name,
+		PackageName: strings.ReplaceAll(name, "_", ""),
+		Schema:      schema,
+		Operations:  operations,
 	}
 
 	applyTransformationsWithConfigOpts(resourceConfig, resource)
@@ -234,7 +234,7 @@ func opResponseToAttributes(op *high.Operation) Attributes {
 	return responseAttributes
 }
 
-func getAPISpecResource(spec *high.Document, resourceConfig *config.Resource, name stringcase.SnakeCaseString) (APISpecResource, error) {
+func getAPISpecResource(spec *high.Document, resourceConfig *config.Resource, name string) (APISpecResource, error) {
 	var errResult error
 	var resourceDeprecationMsg *string