Summary

• Compose undici's built-in interceptors.decompress() onto the dispatcher so gzip/deflate/br/zstd response bodies are decoded before the CLI parses them.
• Suppress undici's one-time ExperimentalWarning for the decompress interceptor so it does not leak to every ol invocation's stderr.

Problem

On Node 24+, attaching any custom dispatcher to global fetch strips the response's content-encoding header but does not actually decompress the body. ol auth status (and the OAuth login flow's auth.info step) fail with Unexpected token '...' is not valid JSON because res.json() is parsing raw gzipped bytes.

Fix

undici 7 ships a built-in decompress interceptor (public API: undici.interceptors.decompress) that handles gzip/deflate/br/zstd, strips content-encoding/content-length from upstream headers (so Node's fetch layer doesn't try to decompress again), and is composed via the standard Dispatcher.prototype.compose(...) API. ~1 line of dispatcher change; preserves wire compression (no Accept-Encoding: identity workaround, no bandwidth regression).

The undici interceptor is currently flagged ExperimentalWarning but is fully implemented and stable for HTTPS gzipped-JSON. The change includes a small suppressExperimentalWarningsSync helper (exported for direct unit testing) that suppresses every ExperimentalWarning during the synchronous dispatcher-init critical section. The synchronous contract is what makes the global process.emitWarning override safe — no unrelated code can interleave during the microsecond window.

Supersedes #62

#62 sidesteps the bug by sending Accept-Encoding: identity so the server skips compression entirely. That works but trades wire bandwidth for simplicity (~70-80% inflation on JSON payloads). Composing the interceptor is the proper fix and preserves compression. Recommend closing #62 once this lands.

This is the same fix already shipped in @doist/todoist-sdk@10.1.3 (Doist/todoist-cli#318) and @doist/twist-sdk@2.5.1. outline-cli has its own transport layer rather than going through a shared SDK, so the fix lives directly in the CLI.

Test plan

• npm test — 129/129 passing, including 4 new dispatcher tests:
  • existing Agent / EnvHttpProxyAgent instanceof + cache + reset assertions still pass (compose preserves the prototype chain)
  • decompresses gzip-encoded response bodies — spins up a node:http server, returns Content-Encoding: gzip with raw gzipped JSON, verifies the dispatcher decodes it
  • suppressExperimentalWarningsSync unit tests — directly verify the helper swallows both emitWarning signatures, restores the original on throw, and returns the callback result
• npm run lint:check — clean
• npm run format:check — clean
• npm run type-check — clean

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