Prototype: replace WpErrorCode fallback with WpErrorCodeValue record

native/kotlin/api/kotlin/src/integrationTest/kotlin/AuthProviderTest.kt

@@ -57,7 +57,7 @@ class AuthProviderTest {
         // Assert that initial unauthorized request fails
         assert(client.request { requestBuilder ->
             requestBuilder.users().retrieveMeWithEditContext()
-        }.wpErrorCode() is WpErrorCode.Unauthorized)
+        }.wpErrorCode() == WpErrorCode.UNAUTHORIZED)
 
         // Assert that request succeeds after setting `is_authorized = true`
         dynamicAuthProvider.isAuthorized = true
@@ -80,7 +80,7 @@ class AuthProviderTest {
         // Assert that request fails without authentication
         assert(client.request { requestBuilder ->
             requestBuilder.users().retrieveMeWithEditContext()
-        }.wpErrorCode() is WpErrorCode.Unauthorized)
+        }.wpErrorCode() == WpErrorCode.UNAUTHORIZED)
 
         // Assert that request succeeds after authentication is modified
         modifiableAuthenticationProvider.setAuthentication(

native/kotlin/api/kotlin/src/integrationTest/kotlin/BlockAutosavesEndpointTest.kt

@@ -56,6 +56,6 @@ class BlockAutosavesEndpointTest {
         val result = client.request { requestBuilder ->
             requestBuilder.blockAutosaves().listWithEditContext(99999999L)
         }
-        assert(result.wpErrorCode() is WpErrorCode.PostInvalidParent)
+        assertEquals(WpErrorCode.POST_INVALID_PARENT, result.wpErrorCode())
     }
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/BlockRendererEndpointTest.kt

@@ -1,11 +1,12 @@
 package rs.wordpress.api.kotlin
 
+import kotlin.test.assertEquals
+
 import kotlinx.coroutines.test.runTest
 import org.junit.jupiter.api.Test
 import uniffi.wp_api.BlockRendererPostParams
 import uniffi.wp_api.WpErrorCode
 import kotlin.test.assertTrue
-
 class BlockRendererEndpointTest {
     private val client = defaultApiClient()
 
@@ -41,7 +42,7 @@ class BlockRendererEndpointTest {
                 params = BlockRendererPostParams()
             )
         }
-        assert(result.wpErrorCode() is WpErrorCode.BlockInvalid)
+        assertEquals(WpErrorCode.BLOCK_INVALID, result.wpErrorCode())
     }
 
     @Test
@@ -52,6 +53,6 @@ class BlockRendererEndpointTest {
                 params = BlockRendererPostParams()
             )
         }
-        assert(result.wpErrorCode() is WpErrorCode.BlockInvalid)
+        assertEquals(WpErrorCode.BLOCK_INVALID, result.wpErrorCode())
     }
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/BlockRevisionsEndpointTest.kt

@@ -77,6 +77,6 @@ class BlockRevisionsEndpointTest {
                 BlockRevisionListParams()
             )
         }
-        assert(result.wpErrorCode() is WpErrorCode.PostInvalidParent)
+        assertEquals(WpErrorCode.POST_INVALID_PARENT, result.wpErrorCode())
     }
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/BlockTypesEndpointTest.kt

@@ -37,6 +37,6 @@ class BlockTypesEndpointTest {
         val result = client.request { requestBuilder ->
             requestBuilder.blockTypes().retrieveWithEditContext("nonexistent", "nonexistent")
         }
-        assert(result.wpErrorCode() is WpErrorCode.BlockTypeInvalid)
+        assertEquals(WpErrorCode.BLOCK_TYPE_INVALID, result.wpErrorCode())
     }
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/BlocksEndpointTest.kt

@@ -73,6 +73,6 @@ class BlocksEndpointTest {
                 BlockListParams(page = 99999999u)
             )
         }
-        assert(result.wpErrorCode() is WpErrorCode.PostInvalidPageNumber)
+        assertEquals(WpErrorCode.POST_INVALID_PAGE_NUMBER, result.wpErrorCode())
     }
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/CategoriesEndpointTest.kt

@@ -123,7 +123,7 @@ class CategoriesEndpointTest {
                         termId = 9999999,
                     )
             }
-        assert(result.wpErrorCode() is WpErrorCode.TermInvalid)
+        assertEquals(WpErrorCode.TERM_INVALID, result.wpErrorCode())
     }
 
     @Test
@@ -136,6 +136,6 @@ class CategoriesEndpointTest {
                         TermCreateParams(name = "foo", parent = 9999999)
                     )
             }
-        assert(result.wpErrorCode() is WpErrorCode.TermInvalid)
+        assertEquals(WpErrorCode.TERM_INVALID, result.wpErrorCode())
     }
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/ErrorCodeForwardCompatTest.kt

@@ -0,0 +1,52 @@
+package rs.wordpress.api.kotlin
+
+import kotlinx.coroutines.test.runTest
+import org.junit.jupiter.api.Test
+import uniffi.wp_api.PostType
+import uniffi.wp_api.WpErrorCode
+import kotlin.test.assertEquals
+import kotlin.test.assertNotNull
+
+class ErrorCodeForwardCompatTest {
+    private val client = defaultApiClient()
+
+    @Test
+    fun testKnownErrorCodeHasValueAndRaw() = runTest {
+        // Trigger a known error: retrieving a non-existent post type
+        val result = client.request { requestBuilder ->
+            requestBuilder.postTypes().retrieveWithEditContext(PostType.Custom("nonexistent_type"))
+        }
+
+        val errorCodeValue = result.wpErrorCodeValue()
+        // `value` should be the known enum variant
+        assertEquals(WpErrorCode.TYPE_INVALID, errorCodeValue.value)
+        // `raw` should always contain the original API string
+        assertEquals("rest_type_invalid", errorCodeValue.raw)
+    }
+
+    @Test
+    fun testWpErrorCodeHelperReturnsKnownVariant() = runTest {
+        // The wpErrorCode() helper extracts .value for convenience
+        val result = client.request { requestBuilder ->
+            requestBuilder.postTypes().retrieveWithEditContext(PostType.Custom("nonexistent_type"))
+        }
+
+        // This is the migration path: use == instead of `is` for enum comparison
+        assertEquals(WpErrorCode.TYPE_INVALID, result.wpErrorCode())
+    }
+
+    @Test
+    fun testRawStringIsAlwaysAvailable() = runTest {
+        // Even for known error codes, the raw string is preserved.
+        // This is the forward-compat guarantee: if a client was written before
+        // a variant existed, they could check the raw string. After the variant
+        // is added, their raw string check still works.
+        val result = client.request { requestBuilder ->
+            requestBuilder.postTypes().retrieveWithEditContext(PostType.Custom("nonexistent_type"))
+        }
+
+        val errorCodeValue = result.wpErrorCodeValue()
+        assertNotNull(errorCodeValue.value, "Known error codes should have a value")
+        assertEquals("rest_type_invalid", errorCodeValue.raw)
+    }
+}

native/kotlin/api/kotlin/src/integrationTest/kotlin/IntegrationTestHelpers.kt

@@ -7,6 +7,7 @@ import uniffi.wp_api.WpApiClientDelegate
 import uniffi.wp_api.WpApiMiddlewarePipeline
 import uniffi.wp_api.WpAuthenticationProvider
 import uniffi.wp_api.WpErrorCode
+import uniffi.wp_api.WpErrorCodeValue
 import uniffi.wp_api.ParsedUrl
 import uniffi.wp_mobile.MockPostService
 import uniffi.wp_mobile.SiteInfo
@@ -94,7 +95,12 @@ fun <T> WpRequestResult<T>.assertSuccessAndRetrieveData(): T {
     return (this as WpRequestResult.Success).response
 }
 
-fun <T> WpRequestResult<T>.wpErrorCode(): WpErrorCode {
+fun <T> WpRequestResult<T>.wpErrorCode(): WpErrorCode? {
+    assert(this is WpRequestResult.WpError)
+    return (this as WpRequestResult.WpError).errorCode.value
+}
+
+fun <T> WpRequestResult<T>.wpErrorCodeValue(): WpErrorCodeValue {
     assert(this is WpRequestResult.WpError)
     return (this as WpRequestResult.WpError).errorCode
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/MenuLocationsEndpointTest.kt

@@ -1,11 +1,12 @@
 package rs.wordpress.api.kotlin
 
+import kotlin.test.assertEquals
+
 import kotlinx.coroutines.test.runTest
 import org.junit.jupiter.api.Test
 import uniffi.wp_api.WpErrorCode
 import kotlin.test.assertNotNull
 import kotlin.test.assertTrue
-
 class MenuLocationsEndpointTest {
     private val client = defaultApiClient()
 
@@ -33,6 +34,6 @@ class MenuLocationsEndpointTest {
             requestBuilder.menuLocations()
                 .retrieveWithViewContext("invalid_location_that_does_not_exist")
         }
-        assert(result.wpErrorCode() is WpErrorCode.MenuLocationInvalid)
+        assertEquals(WpErrorCode.MENU_LOCATION_INVALID, result.wpErrorCode())
     }
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/NavMenuItemsEndpointTest.kt

@@ -1,13 +1,14 @@
 package rs.wordpress.api.kotlin
 
+import kotlin.test.assertEquals
+
 import kotlinx.coroutines.test.runTest
 import org.junit.jupiter.api.Assertions.assertNull
 import org.junit.jupiter.api.Test
 import uniffi.wp_api.NavMenuItemListParams
 import uniffi.wp_api.SparseNavMenuItemFieldWithEditContext
 import uniffi.wp_api.WpErrorCode
 import kotlin.test.assertNotNull
-
 class NavMenuItemsEndpointTest {
     private val testCredentials = TestCredentials.INSTANCE
     private val client = defaultApiClient()
@@ -66,6 +67,6 @@ class NavMenuItemsEndpointTest {
             client.request { requestBuilder ->
                 requestBuilder.navMenuItems().listWithEditContext(params)
             }
-        assert(result.wpErrorCode() is WpErrorCode.PostInvalidPageNumber)
+        assertEquals(WpErrorCode.POST_INVALID_PAGE_NUMBER, result.wpErrorCode())
     }
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/PagesEndpointTest.kt

@@ -72,7 +72,7 @@ class PagesEndpointTest {
             client.request { requestBuilder ->
                 requestBuilder.posts().listWithEditContext(PostEndpointType.Pages, params)
             }
-        assert(result.wpErrorCode() is WpErrorCode.PostInvalidPageNumber)
+        assertEquals(WpErrorCode.POST_INVALID_PAGE_NUMBER, result.wpErrorCode())
     }
 
     @Test

native/kotlin/api/kotlin/src/integrationTest/kotlin/PluginsEndpointTest.kt

@@ -92,14 +92,14 @@ class PluginsEndpointTest {
                 )
             )
         }
-        assert(result.wpErrorCode() is WpErrorCode.CannotInstallPlugin)
+        assertEquals(WpErrorCode.CANNOT_INSTALL_PLUGIN, result.wpErrorCode())
     }
 
     @Test
     fun testDeletePluginErrCannotDeleteActivePlugin() = runTest {
         val result = client.request { requestBuilder ->
             requestBuilder.plugins().delete(PluginSlug(HELLO_DOLLY_PLUGIN_SLUG))
         }
-        assert(result.wpErrorCode() is WpErrorCode.CannotDeleteActivePlugin)
+        assertEquals(WpErrorCode.CANNOT_DELETE_ACTIVE_PLUGIN, result.wpErrorCode())
     }
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/PostStatusesEndpointTest.kt

@@ -63,15 +63,15 @@ class PostStatusesEndpointTest {
             requestBuilder.postStatuses()
                 .retrieveWithViewContext(PostStatusSlug("non_existent_status"))
         }
-        assert(result.wpErrorCode() is WpErrorCode.StatusInvalid)
+        assertEquals(WpErrorCode.STATUS_INVALID, result.wpErrorCode())
     }
 
     @Test
     fun testPostStatusesErrCannotReadStatus() = runTest {
         val result = client.request { requestBuilder ->
             requestBuilder.postStatuses().retrieveWithViewContext(PostStatusSlug("auto-draft"))
         }
-        assert(result.wpErrorCode() is WpErrorCode.CannotReadStatus)
+        assertEquals(WpErrorCode.CANNOT_READ_STATUS, result.wpErrorCode())
     }
 
     @Test

native/kotlin/api/kotlin/src/integrationTest/kotlin/PostTypesEndpointTest.kt

@@ -43,6 +43,6 @@ class PostTypesEndpointTest {
         val result = client.request { requestBuilder ->
             requestBuilder.postTypes().retrieveWithEditContext(PostType.Custom("does_not_exist"))
         }
-        assert(result.wpErrorCode() is WpErrorCode.TypeInvalid)
+        assertEquals(WpErrorCode.TYPE_INVALID, result.wpErrorCode())
     }
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/PostsEndpointTest.kt

@@ -72,7 +72,7 @@ class PostsEndpointTest {
             client.request { requestBuilder ->
                 requestBuilder.posts().listWithEditContext(PostEndpointType.Posts, params)
             }
-        assert(result.wpErrorCode() is WpErrorCode.PostInvalidPageNumber)
+        assertEquals(WpErrorCode.POST_INVALID_PAGE_NUMBER, result.wpErrorCode())
     }
 
     @Test

native/kotlin/api/kotlin/src/integrationTest/kotlin/SidebarsEndpointTest.kt

@@ -1,12 +1,13 @@
 package rs.wordpress.api.kotlin
 
+import kotlin.test.assertEquals
+
 import kotlinx.coroutines.test.runTest
 import org.junit.jupiter.api.Test
 import uniffi.wp_api.SidebarUpdateParams
 import uniffi.wp_api.WpAuthenticationProvider
 import uniffi.wp_api.WpErrorCode
 import kotlin.test.assertTrue
-
 class SidebarsEndpointTest {
     private val testCredentials = TestCredentials.INSTANCE
     private val client = defaultApiClient()
@@ -54,14 +55,14 @@ class SidebarsEndpointTest {
             requestBuilder.sidebars()
                 .retrieveWithViewContext("nonexistent_sidebar_that_does_not_exist")
         }
-        assert(result.wpErrorCode() is WpErrorCode.SidebarNotFound)
+        assertEquals(WpErrorCode.SIDEBAR_NOT_FOUND, result.wpErrorCode())
     }
 
     @Test
     fun testSidebarsErrCannotManageWidgets() = runTest {
         val result = clientAsSubscriber.request { requestBuilder ->
             requestBuilder.sidebars().listWithEditContext()
         }
-        assert(result.wpErrorCode() is WpErrorCode.CannotManageWidgets)
+        assertEquals(WpErrorCode.CANNOT_MANAGE_WIDGETS, result.wpErrorCode())
     }
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/TagsEndpointTest.kt

@@ -115,6 +115,6 @@ class TagsEndpointTest {
                 requestBuilder.terms()
                     .retrieveWithEditContext(TermEndpointType.Tags, 9999999)
             }
-        assert(result.wpErrorCode() is WpErrorCode.TermInvalid)
+        assertEquals(WpErrorCode.TERM_INVALID, result.wpErrorCode())
     }
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/TemplatePartsEndpointTest.kt

@@ -116,6 +116,6 @@ class TemplatePartsEndpointTest {
                 requestBuilder.templateParts()
                     .delete(TEMPLATE_PART_TWENTY_TWENTY_FOUR_HEADER)
             }
-        assert(result.wpErrorCode() is WpErrorCode.InvalidTemplate)
+        assertEquals(WpErrorCode.INVALID_TEMPLATE, result.wpErrorCode())
     }
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/TemplatesEndpointTest.kt

@@ -115,6 +115,6 @@ class TemplatesEndpointTest {
             client.request { requestBuilder ->
                 requestBuilder.templates().delete(TEMPLATE_TWENTY_TWENTY_FOUR_SINGLE)
             }
-        assert(result.wpErrorCode() is WpErrorCode.InvalidTemplate)
+        assertEquals(WpErrorCode.INVALID_TEMPLATE, result.wpErrorCode())
     }
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/ThemesEndpointTest.kt

@@ -1,5 +1,7 @@
 package rs.wordpress.api.kotlin
 
+import kotlin.test.assertEquals
+
 import kotlinx.coroutines.test.runTest
 import org.junit.jupiter.api.Test
 import uniffi.wp_api.SparseThemeFieldWithEditContext
@@ -8,7 +10,6 @@ import uniffi.wp_api.ThemeStylesheet
 import uniffi.wp_api.WpErrorCode
 import kotlin.test.assertNotNull
 import kotlin.test.assertNull
-
 private const val THEME_TWENTY_TWENTY_FIVE: String = "twentytwentyfive"
 
 class ThemesEndpointTest {
@@ -67,6 +68,6 @@ class ThemesEndpointTest {
                 requestBuilder.themes()
                     .retrieveWithEditContext(ThemeStylesheet("invalid_stylesheet"))
             }
-        assert(result.wpErrorCode() is WpErrorCode.ThemeNotFound)
+        assertEquals(WpErrorCode.THEME_NOT_FOUND, result.wpErrorCode())
     }
 }

native/kotlin/api/kotlin/src/integrationTest/kotlin/UsersEndpointTest.kt

@@ -82,7 +82,7 @@ class UsersEndpointTest {
         )
         val result =
             client.request { requestBuilder -> requestBuilder.users().listWithEditContext(params) }
-        assert(result.wpErrorCode() is WpErrorCode.InvalidParam)
+        assertEquals(WpErrorCode.INVALID_PARAM, result.wpErrorCode())
     }
 
     @Test

native/kotlin/api/kotlin/src/main/kotlin/rs/wordpress/api/kotlin/WpRequestResult.kt

@@ -2,13 +2,13 @@ package rs.wordpress.api.kotlin
 
 import uniffi.wp_api.RequestExecutionErrorReason
 import uniffi.wp_api.RequestMethod
-import uniffi.wp_api.WpErrorCode
+import uniffi.wp_api.WpErrorCodeValue
 import uniffi.wp_api.WpRedirect
 
 sealed class WpRequestResult<T> {
     data class Success<T>(val response: T) : WpRequestResult<T>()
     data class WpError<T>(
-        val errorCode: WpErrorCode,
+        val errorCode: WpErrorCodeValue,
         val errorMessage: String,
         val statusCode: UInt,
         val response: String,