The diagnostic showed only sdk: yes/no (window.Telegram presence), not why the
SDK was absent. Capture how the dynamic telegram-web-app.js load resolved —
present / loaded / no-webapp / error / timeout — and surface it as
"sdk-load: <outcome>". error/timeout pinpoint a blocked or hanging telegram.org
(the prime suspect for an empty launch); no-webapp a loaded-but-broken script.
loadTelegramSDK records the outcome (telegramSdkOutcome); collectTelegramDiag
carries it into the screen. Unit tests cover each outcome; the blocked-script
e2e now asserts sdk-load: error.
A Mini App launch on /telegram/ without sign-in data (empty initData) used to
location.replace('/') — bouncing the visitor to the marketing landing. That
destroyed all diagnosability and, on some Android clients that reach the entry
with no initData, simply looked like the app refusing to open.
Replace the bounce with a compact, privacy-safe launch-error screen
(screens/TelegramLaunchError.svelte) that renders a one-screenshot diagnostic
snapshot captured at the moment of failure: SDK/WebApp presence, Telegram
platform/version, whether initData is empty, whether the URL fragment carried
tgWebAppData, the initData field NAMES present/missing (never the signed
values, never an IP), and OS/mobile/browser via User-Agent Client Hints plus
the full User-Agent. A Share button delivers it through the OS share sheet
(clipboard copy on desktop, reusing the GCG no-webview-strand guard); Retry
re-checks in place to recover a late initData without a reload (which would
discard the launch fragment).
This is the instrument to root-cause the Android empty-initData failure, which
is not reproducible in Playwright.
Tests: collectTelegramDiag + shareText/pickTextShare unit tests; the /telegram/
e2e now asserts the diagnostic screen, not a redirect. Docs: ARCHITECTURE.md +
UI_DESIGN.md updated.
Ilia Denisov