fix(dev): --share no longer publishes a 502 link on IPv6-first hosts

[fbehrens]

Problem

On hosts where localhost resolves IPv6-first (all modern macOS), vp run dev --share published a tailnet URL that answered 502 Bad Gateway:

• The dev runner's share path called ensureTailscaleServe({ localPort }) without a host, so the package default pointed tailscale serve at http://127.0.0.1:<port>.
• But the Vite dev server binds localhost (apps/web/vite.config.ts), which resolves to ::1 first on these machines — so Vite listened on IPv6 loopback only.
• Result: curl https://<host>.ts.net:<port>/ → 502, while http://localhost:<port> worked. A bracketed [::1] target is not an option — tailscaled stores it unbracketed and answers unknown proxy destination.

Fix

Pass localHost: "localhost" in the dev-share mapping so tailscaled resolves the proxy target exactly like the dev server did — the mapping and the listener agree by construction, whatever loopback family the OS prefers.

The server's own --tailscale-serve and the pair flow already pass explicit localHost values and are untouched; the 127.0.0.1 default in @t3tools/tailscale stays as-is.

Testing

• Focused test in scripts/lib/dev-share.test.ts asserts the serve invocation is now serve --bg --https=5788 http://localhost:5788; all 8 tests in the file pass.
• vp run --filter @t3tools/scripts typecheck clean for touched scope (one pre-existing unrelated suggestion), lint clean.

Worked on by ox-alpha (opencode harness).

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Note

Low Risk
Dev-only Tailscale share mapping change with a focused unit test; no production auth or data-path impact.

Overview
Fixes vp run dev --share publishing a 502 URL on IPv6-first machines (modern macOS). shareDevServer now passes localHost: "localhost" to ensureTailscaleServe so Tailscale proxies the same host Vite binds, instead of the package default 127.0.0.1.

Adds a test that captures serve args and asserts the target is http://localhost:<port>.

^{Reviewed by Cursor Bugbot for commit afe291d. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Fix --share 502 link on IPv6-first hosts by targeting localhost in shareDevServer

Updates scripts/lib/dev-share.ts to pass localHost: "localhost" to ensureTailscaleServe, aligning the Tailscale serve mapping with the host Vite actually binds. Adds a test in scripts/lib/dev-share.test.ts that captures serve invocation args via a new onServeArgs callback and asserts the target is http://localhost:5788.

^{Macroscope summarized afe291d.}

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[macroscopeapp]

Approvability

Verdict: Skipped

Macroscope did not run approvability analysis for this PR. Macroscope could not determine whether this PR modifies its approvability configuration, so the PR was not approved automatically. A PR that may change the rules that govern approval is never approved automatically.

[t3dotgg]

Note

🤖 GPT-6 Astra (preview) responding on behalf of Theo

This was closed as part of an automated cleanup pass. If you believe it was closed in error, reply here and we will get it reopened.

Closing as superseded by merged #9324. It uses localhost for the shared dev server proxy, which handles the loopback address Vite actually binds on IPv6-first hosts. The focused proxy-argument test is on main too.