Handle more translation errors (#10160)

src/env/index.ts

@@ -10,6 +10,10 @@ const iOSMajorVersion =
   Platform.OS === 'ios' && typeof Platform.Version === 'string'
     ? parseInt(Platform.Version.split('.')[0], 10)
     : 0
+const androidPlatformVersion =
+  Platform.OS === 'android' && typeof Platform.Version === 'number'
+    ? Platform.Version
+    : 0
 
 /**
  * The semver version of the app, specified in our `package.json`.file. On
@@ -49,3 +53,7 @@ export const IS_WEB_FIREFOX: boolean = false
 export const IS_HIGH_DPI: boolean = true
 // ideally we'd use isLiquidGlassAvailable() from expo-glass-effect but checking iOS version is good enough for now
 export const IS_LIQUID_GLASS: boolean = iOSMajorVersion >= 26
+// So we can avoid attempting on-device translation when we know it's unsupported.
+export const IS_TRANSLATION_SUPPORTED: boolean =
+  (IS_IOS && iOSMajorVersion >= 18) ||
+  (IS_ANDROID && androidPlatformVersion > 22)

src/env/index.web.ts

@@ -48,3 +48,4 @@ export const IS_HIGH_DPI: boolean = window.matchMedia(
   '(min-resolution: 2dppx)',
 ).matches
 export const IS_LIQUID_GLASS: boolean = false
+export const IS_TRANSLATION_SUPPORTED: boolean = false

src/lib/translation/index.tsx

@@ -1,18 +1,17 @@
 import {useCallback, useContext, useEffect, useMemo, useState} from 'react'
 import {LayoutAnimation, Platform} from 'react-native'
 import {getLocales} from 'expo-localization'
-import {
-  isTranslationSupported,
-  onTranslateTask,
-} from '@bsky.app/expo-translate-text'
+import {onTranslateTask} from '@bsky.app/expo-translate-text'
 import {type TranslationTaskResult} from '@bsky.app/expo-translate-text/build/ExpoTranslateText.types'
 import {useLingui} from '@lingui/react/macro'
 import {useFocusEffect} from '@react-navigation/native'
 
 import {useGoogleTranslate} from '#/lib/hooks/useGoogleTranslate'
+import {codeToLanguageName} from '#/locale/helpers'
 import {logger} from '#/logger'
+import {useLanguagePrefs} from '#/state/preferences'
 import {useAnalytics} from '#/analytics'
-import {IS_ANDROID, IS_IOS} from '#/env'
+import {IS_ANDROID, IS_IOS, IS_TRANSLATION_SUPPORTED} from '#/env'
 import {Context} from './context'
 import {
   type ContextType,
@@ -25,6 +24,11 @@ import {guessLanguage} from './utils'
 export * from './types'
 export * from './utils'
 
+const E_SAME_AS_SOURCE_LANGUAGE =
+  'Translation result is the same as the source text.'
+const E_EMPTY_RESULT = 'Translation result is empty.'
+const E_INVALID_SOURCE_LANGUAGE = 'Invalid source language'
+
 /**
  * Attempts on-device translation via @bsky.app/expo-translate-text.
  * Uses a lazy import to avoid crashing if the native module isn't linked into
@@ -80,11 +84,11 @@ async function attemptTranslation(
     typeof result.translatedTexts === 'string' ? result.translatedTexts : ''
 
   if (translatedText === input) {
-    throw new Error('Translation result is the same as the source text.')
+    throw new Error(E_SAME_AS_SOURCE_LANGUAGE)
   }
 
   if (translatedText === '') {
-    throw new Error('Translation result is empty.')
+    throw new Error(E_EMPTY_RESULT)
   }
 
   return {
@@ -159,6 +163,7 @@ export function Provider({children}: React.PropsWithChildren<unknown>) {
   >({})
   const [refCounts, setRefCounts] = useState<Record<string, number>>({})
   const ax = useAnalytics()
+  const langPrefs = useLanguagePrefs()
   const {t: l} = useLingui()
   const googleTranslate = useGoogleTranslate()
 
@@ -235,7 +240,7 @@ export function Provider({children}: React.PropsWithChildren<unknown>) {
         googleTranslate: shouldForceGoogleTranslate,
       })
 
-      if (shouldForceGoogleTranslate || !isTranslationSupported()) {
+      if (shouldForceGoogleTranslate || !IS_TRANSLATION_SUPPORTED) {
         await googleTranslate(
           text,
           expectedTargetLanguage,
@@ -280,7 +285,8 @@ export function Provider({children}: React.PropsWithChildren<unknown>) {
             postLanguages: possibleSourceLanguages,
           },
         }))
-      } catch (e) {
+      } catch (err) {
+        const e = err as Error
         logger.error('Failed to translate text on device', {safeMessage: e})
         // On-device translation failed (language pack missing or user
         // dismissed the download prompt).
@@ -295,6 +301,21 @@ export function Provider({children}: React.PropsWithChildren<unknown>) {
           textLength: text.length,
         })
         let errorMessage = l`Device failed to translate :(`
+        if (e.message === E_SAME_AS_SOURCE_LANGUAGE) {
+          errorMessage = l`Translation to the same language is unavailable on your device.`
+        }
+        if (e.message === E_EMPTY_RESULT) {
+          errorMessage = l`No translation received from your device.`
+        }
+        if (
+          expectedSourceLanguage &&
+          e.message.includes(E_INVALID_SOURCE_LANGUAGE)
+        ) {
+          errorMessage = l`${codeToLanguageName(
+            expectedSourceLanguage,
+            langPrefs.appLanguage,
+          )} is not supported by your device.`
+        }
         if (!IS_ANDROID) {
           LayoutAnimation.configureNext(LayoutAnimation.Presets.easeInEaseOut)
         }
@@ -304,7 +325,7 @@ export function Provider({children}: React.PropsWithChildren<unknown>) {
         }))
       }
     },
-    [ax, googleTranslate, l],
+    [ax, googleTranslate, l, langPrefs.appLanguage],
   )
 
   const ctx = useMemo(