fix(push): report connect failures instead of leaving them unhandled

[frankekn]

Summary

A failed push connect takes the whole host process down on Deno, instead of reconnecting.

Conn.new starts the push stream in an async IIFE that is raced against a 300 ms fallback timer (packages/linejs/base/push/conn.ts:120-137):

await new Promise<void>((resolve) => {
	(async () => {
		const socket = await fetchFn(`https://${host}${path}`, { ... });
		if (!socket.body) {
			throw new Error("no body");
		}
		this.resStream = socket.body;
		resolve();
	})();               // not awaited, not caught
	setTimeout(resolve, 300);
});

Nothing awaits or catches that IIFE, and the outer promise is resolved by the timer regardless. When the fetch inside it rejects — a reset connection, DNS trouble, the endpoint refusing the h2 stream — the rejection has nowhere to go and becomes an unhandled rejection:

error: Uncaught (in promise) TypeError: fetch failed

which terminates the process. The no body throw two lines below has the same fate. Any network hiccup is enough, so a listener that runs for days eventually dies from a transient failure rather than reconnecting through the retry loop that already exists for exactly this.

Fix

Attach a .catch() to the IIFE: log the error through client.log("LegyPusherError", { error }) — the same channel initLegyPusher already uses for pusher failures (packages/linejs/base/polling/mod.ts:170) — and resolve().

resStream is then simply left unset, so the next read() throws no resStream and the existing reconnect loop in initLegyPusher (packages/linejs/base/polling/mod.ts:157-173) sleeps 4 s and reconnects, which is what a dropped connection should do. The 300 ms race and the success path are untouched, and reqStream is still handed back so the caller can close the conn.

Testing

New packages/linejs/base/push/conn.test.ts, 3 cases against a stub whose fetch is controlled per test:

1. fetch rejects → new() resolves, one LegyPusherError is logged carrying the original TypeError, resStream stays unset. On main the unhandled rejection is raised instead (Deno's test sanitizer reports it as a failure, the same way the runtime reports it as a crash).
2. A response with no body → same handling, so the no body path is covered too.
3. A successful connect still assigns resStream and logs nothing.

cd packages/linejs && deno test -A — 219 passed, 0 failed (216 on main @ 802f4c7). deno fmt --check and deno check clean on both touched files.

This change is independent of the other pull requests open from this fork; it touches only base/push/conn.ts.

[Copilot]

🟡 Changes recommended

The new .catch() handler can still reintroduce an unhandled rejection if client.log(...) throws (e.g., due to a user-provided log listener), undermining the crash-prevention goal.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

This PR hardens the push connection startup (packages/linejs/base/push/conn.ts) so transport/stream-init failures don’t surface as unhandled promise rejections on Deno, allowing the existing reconnect loop to keep the host process alive.

Changes:

• Catch and report errors from the floating connect IIFE in Conn.new() and resolve the connect race so the caller proceeds into the established reconnect flow.
• Add a dedicated test suite for Conn.new() covering fetch rejection, missing response body, and success behavior.

File summaries

File	Description
packages/linejs/base/push/conn.ts	Adds a .catch() to the connect IIFE to log failures and prevent unhandled rejections from terminating the process.
packages/linejs/base/push/conn.test.ts	Adds tests validating that connect failures are reported (not unhandled) and that successful connects still set resStream.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 1
• Review effort level: Lite

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.