feat(compiler): move translation service initialization to see the logs #1705

AleksandrSl · 2025-12-23T22:42:26Z

Summary

We don't really need to initialize it inside the server, since server is only a way to use the service in the dev mode.

Logs of the server are written to a file due to it being started from process which doesn't have access to console. But we want to see TranslationService initialization logs in the console, and the clearest way is to start it early, rather than extracting validation into a separate function.

Changes

Shows TranslationService logs in the console instead of log file
Sets up e2e tests for compiler

Checklist

Changeset added (if version bump needed)
Tests cover business logic (not just happy path)
No breaking changes (or documented below)

AleksandrSl · 2025-12-23T22:43:42Z

packages/new-compiler/src/plugin/next.ts

    `Initializing Lingo.dev compiler. Is dev mode: ${isDev}. Is main runner: ${isMainRunner()}`,
  );

-  // TODO (AleksandrSl 12/12/2025): Add API keys validation too, so we can log it nicely.


That's what is solved in the PR (beside e2e tests and logs clenaup)

AleksandrSl · 2025-12-23T22:46:27Z

packages/new-compiler/src/translation-server/translation-server.ts

-      if (!this.translationService) {
-        throw new Error("Translation service not initialized");
-      }


Quite dumb check, we make sure TranslationService is never null in constructor, since it's not something heavy we should delay creating

AleksandrSl · 2025-12-23T22:56:34Z

packages/new-compiler/src/translators/pseudotranslator/index.ts

    const delay = this.config?.delayMedian ?? 0;
    const actualDelay = this.getRandomDelay(delay);

-    this.logger.debug(


These were mostly added by LLM for debugging, we can add them back with LLM if needed

We don't really need to initialize it inside the server, since server is only a way to use the service in the dev mode. Logs of the server are written to a file due to it being started from process which doesn't have access to console. But we want to see TranslationService initialization logs in the console, and the clearest way is to start it early, rather than extracting validation into a separate function.

AleksandrSl · 2025-12-24T22:37:52Z

.github/workflows/pr-check.yml

        if: github.event.pull_request.user.login != 'dependabot[bot]'
        run: pnpm changeset status --since origin/main
+
+  compiler-e2e:


Why this is a separate job:

this test should probably be optional for now

it's easier to see which tests failed exactly, e2e or the usual ones

It needs the previous check to pass because if usual tests fail, I don't think it makes a lot of sense to run e2e.

AleksandrSl · 2025-12-24T22:39:31Z

packages/new-compiler/package.json

-    "test:e2e:vite": "playwright test --grep vite --reporter=list",
-    "test:e2e:shared": "playwright test tests/e2e/shared --reporter=list",
+    "test:e2e:prepare": "tsx tests/helpers/prepare-fixtures.ts",
+    "test:e2e": "playwright test",


Reporter is set in the config

AleksandrSl · 2025-12-24T22:39:46Z

packages/new-compiler/package.json

-    "test:e2e:next": "playwright test --grep next --reporter=list",
-    "test:e2e:vite": "playwright test --grep vite --reporter=list",
-    "test:e2e:shared": "playwright test tests/e2e/shared --reporter=list",
+    "test:e2e:prepare": "tsx tests/helpers/prepare-fixtures.ts",


Build is required on turbo side

AleksandrSl · 2025-12-24T22:40:46Z

.github/workflows/pr-check.yml

+      - name: Install dependencies
+        run: pnpm install
+
+      - name: Install Playwright Browsers


Playwright says caching browsers isn't worth it - https://playwright.dev/docs/ci#caching-browsers (and we use only one)

AleksandrSl · 2025-12-24T23:56:05Z

packages/new-compiler/src/plugin/build-translator.ts


  logger.info(`🌍 Build mode: ${buildMode}`);

-  if (metadataFilePath) {


This was internal info

Copilot

Pull request overview

This PR refactors the translation service initialization to display logs in the console instead of a log file, and adds e2e test infrastructure for the compiler package. The key motivation is to make TranslationService initialization errors visible during development since the server process doesn't have console access.

Key Changes:

Moved translator initialization logic from translator-factory.ts into the TranslationService constructor
Renamed Service class to LingoTranslator for clarity
Updated test script naming from test:prepare to test:e2e:prepare throughout the codebase
Added CI workflow for running e2e tests with Playwright
Changed many logging calls from info to debug level to reduce console noise

Reviewed changes

Copilot reviewed 26 out of 27 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
`packages/new-compiler/src/translators/translation-service.ts`	Integrated translator and cache creation directly into TranslationService constructor; removed factory dependency
`packages/new-compiler/src/translators/translator-factory.ts`	Removed entire file as its logic was moved into TranslationService
`packages/new-compiler/src/translators/memory-cache.ts`	New in-memory cache implementation for use with pseudotranslator
`packages/new-compiler/src/translators/lingo/translator.ts`	Renamed Service class to LingoTranslator; reformatted imports
`packages/new-compiler/src/translators/lingo/provider-details.ts`	Removed unused helper functions; simplified error messages
`packages/new-compiler/src/translators/lingo/model-factory.ts`	Updated to use new error formatting; added TODO comment
`packages/new-compiler/src/translators/pluralization/service.ts`	Changed logging levels from info to debug; refactored cache check logic; removed unused methods
`packages/new-compiler/src/translators/pseudotranslator/index.ts`	Removed verbose trace-level debug logs
`packages/new-compiler/src/translation-server/translation-server.ts`	Accept optional TranslationService in constructor; read startPort from config instead of separate parameter
`packages/new-compiler/src/plugin/unplugin.ts`	Create TranslationService before passing to server
`packages/new-compiler/src/plugin/next.ts`	Create TranslationService before passing to server; improved error logging
`packages/new-compiler/src/plugin/build-translator.ts`	Create TranslationService before passing to server; improved error logging
`packages/new-compiler/package.json`	Renamed test scripts from `test:prepare` to `test:e2e:prepare`; removed `--reporter=list` flags
`turbo.json`	Added `test:e2e:prepare` and `test:e2e` tasks with proper dependencies
`.github/workflows/pr-check.yml`	Added new `compiler-e2e` job to run Playwright tests in CI
`packages/new-compiler/tests/*/.md`	Updated documentation to use new `test:e2e:prepare` script name
`packages/new-compiler/tests/helpers/*/.ts`	Updated error messages to reference new script name
`demo/new-compiler-next16/package.json`	Changed workspace dependency specifier from `^1.0.0-beta` to `*`
`pnpm-lock.yaml`	Lockfile updates reflecting dependency changes
`.changeset/sharp-yaks-cough.md`	Added changeset documenting the patch

Files not reviewed (1)

pnpm-lock.yaml: Language not supported

Comments suppressed due to low confidence (1)

packages/new-compiler/src/translators/lingo/translator.ts:7

The import formatting change that combines multiple imports into a single line reduces code readability. The original multi-line format was more readable and easier to maintain. Consider reverting to the multi-line import format for better code clarity.

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

Copilot · 2025-12-25T00:01:37Z

packages/new-compiler/src/translators/memory-cache.ts

+      return hashes.reduce(
+        (acc, hash) => ({ ...acc, [hash]: localeCache.get(hash) }),
+        {},
+      );


The reduce operation on line 21-23 has a potential bug. When a hash is not found in localeCache, localeCache.get(hash) returns undefined, which will be set as the value for that hash in the accumulator. This means the returned object will contain entries with undefined values for missing hashes. Consider filtering out undefined values or only including hashes that exist in the cache.

Suggested change

return hashes.reduce(

(acc, hash) => ({ ...acc, [hash]: localeCache.get(hash) }),

{},

);

return hashes.reduce((acc, hash) => {

const value = localeCache.get(hash);

if (value !== undefined) {

acc[hash] = value;

}

return acc;

}, {} as Record<string, string>);

Copilot · 2025-12-25T00:01:37Z

packages/new-compiler/src/translators/memory-cache.ts

+  constructor() {}
+


The empty constructor serves no purpose and can be removed. TypeScript doesn't require an explicit constructor if there's no initialization logic.

Suggested change

constructor() {}

Copilot · 2025-12-25T00:01:37Z

packages/new-compiler/src/translators/translation-service.ts

+          this.logger.warn(`⚠️ Translation setup error: \n${errorMsg}\n
+⚠️ Auto-fallback to pseudotranslator in development mode.
+Set the required API keys for real translations.`);


The multi-line string literal uses a backtick template with embedded newlines, but this creates a string with leading whitespace on lines 121-122. The indentation in the source code will be included in the output message, which may look incorrect when logged. Consider using a dedented template literal or joining separate strings.

Suggested change

this.logger.warn(`⚠️ Translation setup error: \n${errorMsg}\n

⚠️ Auto-fallback to pseudotranslator in development mode.

Set the required API keys for real translations.`);

this.logger.warn(

`⚠️ Translation setup error: \n${errorMsg}\n` +

"⚠️ Auto-fallback to pseudotranslator in development mode.\n" +

"Set the required API keys for real translations.",

);

AleksandrSl commented Dec 23, 2025

View reviewed changes

AleksandrSl force-pushed the feat/compiler-show-translation-service-logs-in-console branch 3 times, most recently from 91c0bef to 85ceb48 Compare December 23, 2025 23:35

AleksandrSl added 3 commits December 24, 2025 00:51

fix: new ai sdk api compatibility

861ca01

chore: add changeset

bed9c1f

AleksandrSl force-pushed the feat/compiler-show-translation-service-logs-in-console branch from 85ceb48 to bed9c1f Compare December 23, 2025 23:51

AleksandrSl added 4 commits December 24, 2025 22:46

feat: add compiler e2e tests

6aa0e9a

fix: run tests preparation through turbo

fce5c3a

fix: limit installed browsers to chromium and fix trubo config

790182e

fix: run build before tests

55431fe

AleksandrSl commented Dec 24, 2025

View reviewed changes

AleksandrSl added 3 commits December 24, 2025 23:52

fix: get rid of noisy logs

fb8ca8c

fix: cleanup logs and unused functions

196b8f8

fix: compiler version in next demo

688a1c5

AleksandrSl commented Dec 24, 2025

View reviewed changes

AleksandrSl requested review from Copilot and maxprilutskiy December 24, 2025 23:57

Copilot started reviewing on behalf of AleksandrSl December 24, 2025 23:58 View session

Copilot AI reviewed Dec 25, 2025

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feat(compiler): move translation service initialization to see the logs #1705

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AleksandrSl commented Dec 23, 2025 •

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		logger.info(`🌍 Build mode: ${buildMode}`);

		if (metadataFilePath) {

-      return hashes.reduce(
-        (acc, hash) => ({ ...acc, [hash]: localeCache.get(hash) }),
-        {},
-      );
+      return hashes.reduce((acc, hash) => {
+        const value = localeCache.get(hash);
+        if (value !== undefined) {
+          acc[hash] = value;
+        }
+        return acc;
+      }, {} as Record<string, string>);

feat(compiler): move translation service initialization to see the logs #1705

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AleksandrSl commented Dec 23, 2025 •

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