Speed up frontend builds: patch pofile, switch to SWC

[daveearley]

Why

Staging frontend deploys on DigitalOcean went from ~6.5 min to ~25 min starting with #1411 (6m 54s on Oct 17 06:21 → 17m 46s at 21:37 → 24m 54s today).

Phase timings from the DO build logs:

Step	Before (122ef58)	After (b30bc05)
lingui extract	13s	42s
lingui compile	23s	5m 7s
client vite build	1m 9s	6m 36s
SSR vite build	39s	5m 33s

The code barely changed (+37 modules), but each locale .po file grew from 15,926 to 16,669 lines. That crossed V8's ~16.4k-element limit for constant-time Array.prototype.shift(). pofile (used by @lingui/format-po) parses with while (lines.length > 0) { lines.shift() … }, so each parse turned quadratic: about 9ms → 55ms per catalog. Lingui parses every catalog many times per locale, in lingui compile and again in the Vite plugin for both the client and SSR builds, so every step slowed 5–10x. pofile has had no release since 2022.

What

• Patch pofile with patch-package to iterate by index. Parse time is flat again (~150ms for all 21 catalogs at every commit tested).
• Babel → SWC: @vitejs/plugin-react-swc + @lingui/swc-plugin@4.1.0 replace @vitejs/plugin-react with the Babel macros plugin. @swc/core is pinned to 1.7.42 via resolutions, the range the Lingui 4 SWC plugin supports.
• Drop lingui compile from build and Dockerfile.ssr. The app loads catalogs with import(\./locales/${locale}.po`)through@lingui/vite-plugin, so the compiled .jsoutput is never used.messages:extractstays inbuild`: it's the only guard against a string missing from the catalogs, which would render as its hashed id in production.
• Docker: copy patches/ into the install stages so the patch applies. The production-only install in Dockerfile.ssr drops the postinstall hook, because neither patch-package nor pofile is installed there.

Results (CI, Dockerfile.ssr build step on GitHub runners)

	lingui compile	client build	SSR build	total
develop before the slowdown (122ef58)	14s	33s	24s	~72s
develop now (b30bc05)	77s	2m 6s	1m 37s	~302s
this PR	(removed)	1m 6s	35s	~104s

The client build is still above the pre-slowdown figure because #1412 added the Scalar API reference (+5,900 modules). On this PR's first run, the step's total wall time also includes an uncached dependency install (the lockfile changed) and re-exporting every layer to the Actions cache.

Results (local, Node 24, Apple Silicon)

Step	Before	After
lingui compile	17.4s	8.0s (and no longer in the build)
client vite build	30.6s	19.4s
SSR vite build	22.5s	11.0s

DO's builder is roughly 5–10x slower than a laptop on these CPU-bound steps.

Behaviour checks

• Message ids in the client bundle match the Babel build, with two extra ids. Those are nested t macros (t\Sold to ${name ?? t`an attendee`}`) that Babel never expanded: the inner tshipped as a call to whatever minified variable was namedt`. SWC expands them correctly, so this also fixes that.
• Production stripping still applies (same asset size, no inline source strings).
• The production SSR server renders translated pages (de, fr) and hydrates. The Dockerfile.ssr image builds, applies the patch in deps, and serves pages.
• In the dev server, macros are transformed and Fast Refresh is wired.
• lingui extract leaves the catalogs unchanged, and lingui compile output is byte-identical.

Notes

• The dev stack needs a rebuild after pulling, because the frontend container keeps its own node_modules volume: docker compose -f docker-compose.dev.yml up -d --build -V frontend

[railway-app]

🚅 Deployed to the Hi.Events-pr-1415 environment in Hi.Events

Service	Status	Web	Updated
Hi.Events Frontend	😴 Sleeping (View Logs)	Web	Oct 18, 2026 at 12:43 pm UTC
Hi.Events API	✅ Success (View Logs)	Web	Oct 18, 2026 at 12:21 pm UTC

3 services not affected by this PR

• Hi.Events Scheduler
• Hi.Events Queue Worker
• Maildev

[github-actions]

⚠️ E2E full suite (pull request): Everything passed, but 4 tests only passed on retry.

Mode	Result	✅ Passed	❌ Failed	⚠️ Flaky	⏭️ Skipped	⏱️ Duration
Self-hosted	⚠️ Passed (some flaky)	592	0	2	4	14m 28s
SaaS	⚠️ Passed (some flaky)	580	0	2	16	13m 49s

⚠️ Flaky tests: failed first, then passed on retry (4)

• SaaS · seating/seating-flag-off.spec.ts:92 · reserved seating with the feature flag off on Hi.Events Cloud › a seated event cannot be duplicated into unseated tickets while seating is off
• SaaS · widget/widget-editor.spec.ts:104 · widget editor › organizers embed their events list from the organizer area
• Self-hosted · widget/widget-editor.spec.ts:104 · widget editor › organizers embed their events list from the organizer area
• Self-hosted · widget/widget-playground.spec.ts:29 · widget playground › the playground embeds an organizer events list as a custom element

⏭️ Why tests were skipped

Self-hosted

• 3 × Runs only against a SaaS stack (E2E_SAAS_MODE=true).
• 1 × Lifecycle emails only exist in SaaS mode.

SaaS

• 15 × Runs only against a non-SaaS stack (E2E_SAAS_MODE=false).
• 1 × The composer form is gated behind Stripe/manual account verification in SaaS mode.

Open the run