extension_startup_reliability

The platform spinner ends only after VS Code loads the host module, calls `activate`, the provider registers, and `resolveWebviewView` assigns HTML. Reqlan assigns the lightweight HTML / Svelte shell first. The webview installs its host message listener, mounts, waits for its first animation frame, then posts the one-shot `ready` signal from a queued task. Index discovery / sync waits for that post-paint signal so synchronous parser or database setup cannot race the first visible frame. [activation.first_paint_startup] ["../../packages/extension/webviews/activity-bar/App.svelte"] ["../../packages/extension/webviews/activity-bar/state/app.svelte.ts"] ["../../packages/extension/src/extension/startup-gate.ts"]

Required order: 1. Load the smallest practical host entry. 2. Synchronously register commands and the activity-bar provider; return from `activate`. 3. Assign the activity-bar shell and wait for the post-first-frame `ready` handshake. 4. Start index discovery / sync after `ready`; if the sidebar stays closed, start after a bounded three-second fallback so startup indexing and watchers are not lost. 5. Start the language client after `ready`, with a one-second fallback so language features work when the sidebar stays closed. 6. Report incremental index progress inside the already-painted sidebar. The ready signal and both startup paths are one-shot / idempotent. [activation.background_startup]

Base discovery must be cheap: - Constructing `WorkspaceIndex` does not construct Langium / Chevrotain services; services are memoized on first parse. - sql. js asm is not parsed as part of `main.cjs`; both index stores dynamically import the generated vendor bundle when a database first opens. - Export / physics source is generated at build time rather than read via extension-runtime URLs. The host bundle consequently fell from approximately 11. 2 MB to 2. 66 MB; sql. js occupies a separate approximately 8. 0 MB lazy vendor bundle. ["../../packages/analytical/src/index-store/workspace-index.ts"] ["../../packages/analytical/src/index-store/sqlite-store.ts"] ["../../packages/analytical/src/index-store/index-diagnostics-store.ts"] ["../../packages/extension/esbuild.mjs"]

F5 executes `package.json.main` ( `out/extension/main.cjs` ), not TypeScript source. `out/`, generated webview media, and copied syntaxes are gitignored, so launching without a build can run missing or stale artifacts even when source already contains the fix. `.vscode/launch.json` therefore uses a deterministic pre-launch task that invokes the extension build orchestrator directly; root `pnpm run build:ext` delegates to the same script. The task content-fingerprints Langium and physics generation, each webview, packaging media, and extension-host / language-server output; `tsc -b` retains project-reference incrementality. Unchanged artifacts are verified and skipped before the development host opens. Watch mode remains useful during iteration, but concurrent watchers do not restart an already-running extension host or language-server child; stop and start F5 after host / server changes. ["../../.vscode/launch.json"] ["../../.vscode/tasks.json"]

Diagnosis order: 1. Read the development extension host's `remoteexthost.log`; find `ExtensionService#_doActivateExtension reqlan.reqlan-extension`. 2. Distinguish code-loading time, activate-call time, and activate-resolved time. 3. If activation failed, use the first Reqlan stack frame rather than inferring a CPU hang. 4. If manifest UI exists but every command is missing, investigate module load / activation before indexing or webview data. 5. If the extension-owned " Loading Reqlan … " shell appears, provider resolution succeeded; subsequent delays belong to webview bootstrap or index readiness. 6. Confirm `out/extension/main.cjs` is newer than changed source and includes lazy `import("./vendor/sql-asm.cjs")`. CPU-idle profiles do not disprove activation failure: once `require()` throws, the host can remain healthy and mostly idle while Reqlan stays unregistered.