fix: redirect loop on initial load (static mode & route with no locale)

On initial load, if:
  - the Nuxt target was set to "static"
  - the loaded route had locales disabled

Then we've attempted to redirect even when redirect path equaled the
current path. That has triggered an infinite redirect loop.

Fix by not setting a redirect when it matches the current path.

Resolves #798

src/templates/plugin.main.js

@@ -118,9 +118,10 @@ export default async (context) => {
     if (!redirectPath) {
       // Current route could be 404 in which case attempt to find matching route for given locale.
       redirectPath = app.localePath(route.fullPath, locale)
-      if (redirectPath === route.fullPath) {
-        return ''
-      }
+    }
+
+    if (redirectPath === route.fullPath) {
+      return ''
     }
 
     return redirectPath

test/browser.test.js

@@ -136,6 +136,48 @@ describe(browserString, () => {
   })
 })
 
+describe(`${browserString}, target: static, trailingSlash: true`, () => {
+  /** @type {Nuxt} */
+  let nuxt
+  /** @type {import('playwright-chromium').ChromiumBrowser} */
+  let browser
+  /** @type {import('playwright-chromium').Page} */
+  let page
+
+  beforeAll(async () => {
+    const overrides = {
+      target: 'static',
+      router: {
+        trailingSlash: true
+      },
+      i18n: {
+        parsePages: false,
+        pages: {
+          'about-no-locale': false
+        }
+      }
+    }
+    nuxt = (await setup(loadConfig(__dirname, 'basic', overrides, { merge: true }))).nuxt
+    browser = await createBrowser()
+  })
+
+  afterAll(async () => {
+    if (browser) {
+      await browser.close()
+    }
+
+    await nuxt.close()
+  })
+
+  // Issue https://github.com/nuxt-community/i18n-module/issues/798
+  // Not specific to trailingSlash === true
+  test('does not trigger redirect loop on route with disabled locale', async () => {
+    page = await browser.newPage()
+    await page.goto(url('/about-no-locale/'), { waitUntil: 'load', timeout: 2000 })
+    expect(await (await page.$('body'))?.textContent()).toContain('page: About us')
+  })
+})
+
 describe(`${browserString} (generate)`, () => {
   /** @type {import('playwright-chromium').ChromiumBrowser} */
   let browser
@@ -208,9 +250,9 @@ describe(`${browserString} (generate)`, () => {
     page = await browser.newPage()
     await page.goto(server.getUrl('/'))
     /**
-       * @param {string} route
-       * @param {string | undefined} [locale]
-       */
+     * @param {string} route
+     * @param {string | undefined} [locale]
+     */
     const localePath = async (route, locale) => {
       // @ts-ignore
       return await page.evaluate(args => window.$nuxt.localePath(...args), [route, locale])
@@ -221,7 +263,7 @@ describe(`${browserString} (generate)`, () => {
   })
 })
 
-describe(`${browserString} (generate, no subFolders, no trailingSlash)`, () => {
+describe(`${browserString} (generate, no subFolders, trailingSlash === false)`, () => {
   /** @type {import('playwright-chromium').ChromiumBrowser} */
   let browser
   /** @type {import('playwright-chromium').Page} */

test/fixture/basic/pages/about-no-locale.vue

@@ -0,0 +1,17 @@
+<template>
+  <div>
+    <LangSwitcher />
+    <div id="current-page">page: {{ $t('about') }}</div>
+    <nuxt-link id="link-home" exact :to="localePath('index')">{{ $t('home') }}</nuxt-link>
+  </div>
+</template>
+
+<script>
+import LangSwitcher from '../components/LangSwitcher'
+
+export default {
+  components: {
+    LangSwitcher
+  }
+}
+</script>

test/module.test.js

@@ -1265,7 +1265,7 @@ describe('parsePages disabled', () => {
       i18n: {
         parsePages: false,
         pages: {
-          about: false,
+          'about-no-locale': false,
           simple: {
             en: '/simple-en',
             fr: '/simple-fr'
@@ -1290,8 +1290,18 @@ describe('parsePages disabled', () => {
   })
 
   test('navigates to route with paths disabled in pages option', async () => {
-    await expect(get('/about')).resolves.toBeDefined()
-    await expect(get('/fr/about')).rejects.toBeDefined()
+    await expect(get('/about-no-locale')).resolves.toBeDefined()
+    await expect(get('/fr/about-no-locale')).rejects.toBeDefined()
+  })
+
+  test('does not trigger redirect loop on route with disabled locale', async () => {
+    const requestOptions = {
+      followRedirect: false,
+      resolveWithFullResponse: true,
+      simple: false // Don't reject on non-2xx response
+    }
+    const response = await get('/about-no-locale', requestOptions)
+    expect(response.statusCode).toBe(200)
   })
 })