fix CreateString function to create valid utf8 strings

Signed-off-by: kstiehl <[email protected]>

Author: kstiehl

go.mod

@@ -12,6 +12,7 @@ require (
 	github.com/hashicorp/terraform-plugin-framework-validators v0.19.0
 	github.com/hashicorp/terraform-plugin-go v0.29.0
 	github.com/hashicorp/terraform-plugin-testing v1.14.0
+	github.com/stretchr/testify v1.10.0
 	golang.org/x/crypto v0.45.0
 )
 
@@ -20,6 +21,7 @@ require (
 	github.com/agext/levenshtein v1.2.2 // indirect
 	github.com/apparentlymart/go-textseg/v15 v15.0.0 // indirect
 	github.com/cloudflare/circl v1.6.1 // indirect
+	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
 	github.com/fatih/color v1.16.0 // indirect
 	github.com/golang/protobuf v1.5.4 // indirect
 	github.com/hashicorp/errwrap v1.1.0 // indirect
@@ -49,6 +51,7 @@ require (
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/mitchellh/reflectwalk v1.0.2 // indirect
 	github.com/oklog/run v1.1.0 // indirect
+	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/vmihailenco/msgpack v4.0.4+incompatible // indirect
 	github.com/vmihailenco/msgpack/v5 v5.4.1 // indirect
 	github.com/vmihailenco/tagparser/v2 v2.0.0 // indirect
@@ -63,4 +66,5 @@ require (
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20250707201910-8d1bb00bc6a7 // indirect
 	google.golang.org/grpc v1.75.1 // indirect
 	google.golang.org/protobuf v1.36.9 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

internal/provider/resource_password.go

@@ -523,7 +523,6 @@ func upgradePasswordStateV2toV3(ctx context.Context, req resource.UpgradeStateRe
 
 	// Regenerate the BcryptHash value.
 	newBcryptHash, err := bcrypt.GenerateFromPassword([]byte(passwordDataV2.Result.ValueString()), bcrypt.DefaultCost)
-
 	if err != nil {
 		resp.Diagnostics.AddError(
 			"Version 3 State Upgrade Error",
@@ -613,7 +612,8 @@ func passwordSchemaV3() schema.Schema {
 				Default:     booldefault.StaticBool(true),
 				PlanModifiers: []planmodifier.Bool{
 					boolplanmodifier.RequiresReplace(),
-				}},
+				},
+			},
 
 			"lower": schema.BoolAttribute{
 				Description: "Include lowercase alphabet characters in the result. Default value is `true`.",

internal/random/string.go

@@ -27,14 +27,14 @@ func CreateString(input StringParams) ([]byte, error) {
 	const numChars = "0123456789"
 	const lowerChars = "abcdefghijklmnopqrstuvwxyz"
 	const upperChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
-	var specialChars = "!@#$%&*()-_=+[]{}<>:?"
-	var result []byte
+	specialChars := "!@#$%&*()-_=+[]{}<>:?"
+	var result []rune
 
 	if input.OverrideSpecial != "" {
 		specialChars = input.OverrideSpecial
 	}
 
-	var chars = ""
+	chars := ""
 	if input.Upper {
 		chars += upperChars
 	}
@@ -59,7 +59,7 @@ func CreateString(input StringParams) ([]byte, error) {
 		specialChars: input.MinSpecial,
 	}
 
-	result = make([]byte, 0, input.Length)
+	result = make([]rune, 0, input.Length)
 
 	for k, v := range minMapping {
 		s, err := generateRandomBytes(&k, v)
@@ -85,10 +85,10 @@ func CreateString(input StringParams) ([]byte, error) {
 		return order[i] < order[j]
 	})
 
-	return result, nil
+	return []byte(string(result)), nil
 }
 
-func generateRandomBytes(charSet *string, length int64) ([]byte, error) {
+func generateRandomBytes(charSet *string, length int64) ([]rune, error) {
 	if charSet == nil {
 		return nil, errors.New("charSet is nil")
 	}
@@ -97,14 +97,17 @@ func generateRandomBytes(charSet *string, length int64) ([]byte, error) {
 		return nil, errors.New("charSet is empty")
 	}
 
-	bytes := make([]byte, length)
-	setLen := big.NewInt(int64(len(*charSet)))
+	runeSet := []rune(*charSet)
+
+	bytes := make([]rune, length)
+	setLen := big.NewInt(int64(len(runeSet)))
 	for i := range bytes {
 		idx, err := rand.Int(rand.Reader, setLen)
 		if err != nil {
 			return nil, err
 		}
-		bytes[i] = (*charSet)[idx.Int64()]
+		character := runeSet[idx.Int64()]
+		bytes[i] = character
 	}
 	return bytes, nil
 }

internal/random/string_test.go

@@ -0,0 +1,25 @@
+package random_test
+
+import (
+	"testing"
+	"unicode/utf8"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"github.com/terraform-providers/terraform-provider-random/internal/random"
+)
+
+func TestCreateString(t *testing.T) {
+	input := random.StringParams{
+		MinSpecial:      5,
+		Special:         true,
+		Length:          10,
+		OverrideSpecial: "°",
+	}
+	result, err := random.CreateString(input)
+	stringResult := string(result)
+
+	assert.True(t, utf8.ValidString(stringResult), "a valid string is expected here")
+	assert.Equal(t, 10, utf8.RuneCountInString(stringResult))
+	require.NoError(t, err)
+}