Update UpdateUserOpts to allow nil values to remove metadata fields (#453)

* Update UpdateUserOpts to allow for nil values so developers can remove metadata fields

* Remove changelog file

Author: awolfden

pkg/usermanagement/README.md

@@ -13,3 +13,18 @@ go get -u github.com/workos/workos-go/v4/pkg/usermanagement
 ## How it works
 
 See the [User Management integration guide](https://workos.com/docs/user-management/).
+
+### Update user metadata and remove a key by sending JSON null
+
+To set a metadata value to null (and remove it server-side), pass a `nil` pointer for that key. The `Metadata` field accepts `map[string]*string`.
+
+```go
+lang := "en"
+user, err := usermanagement.UpdateUser(ctx, usermanagement.UpdateUserOpts{
+  User: "user_123",
+  Metadata: map[string]*string{
+    "language": &lang,
+    "legacy_code": nil, // serializes as JSON null
+  },
+})
+```

pkg/usermanagement/client.go

@@ -213,15 +213,15 @@ const (
 
 type UpdateUserOpts struct {
 	User             string
-	Email            string            `json:"email,omitempty"`
-	FirstName        string            `json:"first_name,omitempty"`
-	LastName         string            `json:"last_name,omitempty"`
-	EmailVerified    bool              `json:"email_verified,omitempty"`
-	Password         string            `json:"password,omitempty"`
-	PasswordHash     string            `json:"password_hash,omitempty"`
-	PasswordHashType PasswordHashType  `json:"password_hash_type,omitempty"`
-	ExternalID       string            `json:"external_id,omitempty"`
-	Metadata         map[string]string `json:"metadata,omitempty"`
+	Email            string             `json:"email,omitempty"`
+	FirstName        string             `json:"first_name,omitempty"`
+	LastName         string             `json:"last_name,omitempty"`
+	EmailVerified    bool               `json:"email_verified,omitempty"`
+	Password         string             `json:"password,omitempty"`
+	PasswordHash     string             `json:"password_hash,omitempty"`
+	PasswordHashType PasswordHashType   `json:"password_hash_type,omitempty"`
+	ExternalID       string             `json:"external_id,omitempty"`
+	Metadata         map[string]*string `json:"metadata,omitempty"`
 }
 
 type DeleteUserOpts struct {

pkg/usermanagement/client_test.go

@@ -526,6 +526,64 @@ func updateUserTestHandler(w http.ResponseWriter, r *http.Request) {
 	w.Write(body)
 }
 
+func TestUpdateUser_MetadataJSONSerialization_StringValues(t *testing.T) {
+	lang := "en"
+	opts := UpdateUserOpts{
+		Metadata: map[string]*string{
+			"language": &lang,
+		},
+	}
+
+	b, err := json.Marshal(opts)
+	require.NoError(t, err)
+
+	var got map[string]interface{}
+	require.NoError(t, json.Unmarshal(b, &got))
+
+	meta, ok := got["metadata"].(map[string]interface{})
+	require.True(t, ok)
+	require.Equal(t, "en", meta["language"])
+}
+
+func TestUpdateUser_MetadataJSONSerialization_NilValueAsNull(t *testing.T) {
+	opts := UpdateUserOpts{
+		Metadata: map[string]*string{
+			"legacy_code": nil,
+		},
+	}
+
+	b, err := json.Marshal(opts)
+	require.NoError(t, err)
+
+	// Check raw contains null for the key
+	require.Contains(t, string(b), "\"legacy_code\":null")
+
+	var got map[string]interface{}
+	require.NoError(t, json.Unmarshal(b, &got))
+
+	meta, ok := got["metadata"].(map[string]interface{})
+	require.True(t, ok)
+	// JSON null becomes a nil interface value when decoding into map[string]any
+	_, present := meta["legacy_code"]
+	require.True(t, present)
+	require.Nil(t, meta["legacy_code"])
+}
+
+func TestUpdateUser_MetadataJSONSerialization_EmptyMapOmitted(t *testing.T) {
+	opts := UpdateUserOpts{
+		Metadata: map[string]*string{},
+	}
+
+	b, err := json.Marshal(opts)
+	require.NoError(t, err)
+
+	var got map[string]interface{}
+	require.NoError(t, json.Unmarshal(b, &got))
+
+	_, present := got["metadata"]
+	require.False(t, present)
+}
+
 func TestDeleteUser(t *testing.T) {
 	tests := []struct {
 		scenario string