breaking: drop fully preserve modifier codes on v-t directive (#1828)

Author: kazupon

docs/guide/migration/breaking.md

@@ -314,7 +314,6 @@ console.log(VueI18n.availability)
 
 > [!CAUTION]
 > `preserveDirectiveContent` option implementation code is be going to fully remove in v10.
-> As an alternative.
 
 The `v-t` directive for Vue 3 now preserves the default content. Therefore, this option and its properties have been removed from the VueI18n instance.
 
@@ -420,6 +419,9 @@ const messages = {
 
 ### Remove `preserve` modifier
 
+> [!CAUTION]
+> `preserve` modifier implementation code is be going to fully remove in v10.
+
 Similar to *[Remove `preserveDirectiveContent` option](#remove-preservedirectivecontent-option)*, the `v-t` directive for Vue 3 now preserves the default content. Therefore, `preserve` modifier and it’s have been removed from `v-t` directive.
 
 Vue I18n v8.x:

packages/vue-i18n-core/src/directive.ts

@@ -1,13 +1,6 @@
 import { watch } from 'vue'
-import { I18nWarnCodes, getWarnMessage } from './warnings'
 import { createI18nError, I18nErrorCodes } from './errors'
-import {
-  isString,
-  isPlainObject,
-  isNumber,
-  warn,
-  inBrowser
-} from '@intlify/shared'
+import { isString, isPlainObject, isNumber, inBrowser } from '@intlify/shared'
 
 import type {
   DirectiveBinding,
@@ -89,16 +82,13 @@ export type TranslationDirective<T = HTMLElement> = ObjectDirective<T>
 
 export function vTDirective(i18n: I18n): TranslationDirective<HTMLElement> {
   const _process = (binding: DirectiveBinding): [string, Composer] => {
-    const { instance, modifiers, value } = binding
+    const { instance, value } = binding
     /* istanbul ignore if */
     if (!instance || !instance.$) {
       throw createI18nError(I18nErrorCodes.UNEXPECTED_ERROR)
     }
 
     const composer = getComposer(i18n, instance.$)
-    if (__DEV__ && modifiers.preserve) {
-      warn(getWarnMessage(I18nWarnCodes.NOT_SUPPORTED_PRESERVE))
-    }
 
     const parsedValue = parseValue(value)
     return [

packages/vue-i18n-core/src/warnings.ts

@@ -6,19 +6,17 @@ const inc = incrementer(code)
 
 export const I18nWarnCodes = {
   FALLBACK_TO_ROOT: code, // 8
-  NOT_SUPPORTED_PRESERVE: inc(), // 9
-  NOT_SUPPORTED_GET_CHOICE_INDEX: inc(), // 10
-  COMPONENT_NAME_LEGACY_COMPATIBLE: inc(), // 11
-  NOT_FOUND_PARENT_SCOPE: inc(), // 12
-  IGNORE_OBJ_FLATTEN: inc(), // 13
-  NOTICE_DROP_TRANSLATE_EXIST_COMPATIBLE_FLAG: inc() // 14
+  NOT_SUPPORTED_GET_CHOICE_INDEX: inc(), // 9
+  COMPONENT_NAME_LEGACY_COMPATIBLE: inc(), // 10
+  NOT_FOUND_PARENT_SCOPE: inc(), // 11
+  IGNORE_OBJ_FLATTEN: inc(), // 12
+  NOTICE_DROP_TRANSLATE_EXIST_COMPATIBLE_FLAG: inc() // 13
 } as const
 
 type I18nWarnCodes = (typeof I18nWarnCodes)[keyof typeof I18nWarnCodes]
 
 export const warnMessages: { [code: number]: string } = {
   [I18nWarnCodes.FALLBACK_TO_ROOT]: `Fall back to {type} '{key}' with root locale.`,
-  [I18nWarnCodes.NOT_SUPPORTED_PRESERVE]: `Not supported 'preserve'.`,
   [I18nWarnCodes.NOT_SUPPORTED_GET_CHOICE_INDEX]: `Not supported 'getChoiceIndex'.`,
   [I18nWarnCodes.COMPONENT_NAME_LEGACY_COMPATIBLE]: `Component name legacy compatible: '{name}' -> 'i18n'`,
   [I18nWarnCodes.NOT_FOUND_PARENT_SCOPE]: `Not found parent scope. use the global scope.`,

packages/vue-i18n-core/test/diretive.test.ts

@@ -141,36 +141,6 @@ test('plural', async () => {
   expect(wrapper.html()).toEqual('<p>2 bananas</p>')
 })
 
-test('preserve modifier', async () => {
-  const mockWarn = vi.spyOn(shared, 'warn')
-  mockWarn.mockImplementation(() => {})
-
-  const i18n = createI18n({
-    locale: 'en',
-    messages: {
-      en: {
-        hello: 'hello!'
-      }
-    }
-  })
-
-  const App = defineComponent({
-    setup() {
-      // <p v-t.preserve="'hello'"></p>
-      const t = resolveDirective('t')
-      return () => {
-        return withDirectives(h('p'), [[t!, 'hello', '', { preserve: true }]])
-      }
-    }
-  })
-  await mount(App, i18n)
-
-  expect(mockWarn).toHaveBeenCalledTimes(1)
-  expect(mockWarn.mock.calls[0][0]).toEqual(
-    getWarnMessage(I18nWarnCodes.NOT_SUPPORTED_PRESERVE)
-  )
-})
-
 test('legacy mode', async () => {
   const i18n = createI18n({
     legacy: true,