fix #258: detect text streams without Transfer-Encoding (HTTP/2)

[NeilTheFisher]

Closes #258.

Transfer-Encoding: chunked is forbidden in HTTP/2 (RFC 7540 §8.1.2.2) and stripped by reverse proxies on h1→h2. The detection added in #213 requires that header, so any plain-text streaming route hangs forever when served behind Traefik / nginx / Caddy / Cloudflare with HTTPS. Eden falls into await response.text() and a while (true) generator never resolves.

The chunked clause is also redundant — chunked and Content-Length are mutually exclusive (RFC 7230 §3.3.1), so any HTTP/1.1 chunked response already satisfies the existing !has('content-length') check. Dropping the chunked clause keeps h1 working and fixes h2.

Does not regress #213

A non-streaming text/plain response continues to be buffered because it carries Content-Length. The new test still buffers text/plain when Content-Length is present covers this.

Tests

Three new tests in Treaty2 - HTTP/2 streaming detection (#258):

1. text/plain + no Transfer-Encoding → streams (the h2 case; fails on main, passes here)
2. text/plain + Transfer-Encoding: chunked → still streams (h1 regression guard)
3. text/plain + Content-Length → buffers (Eden doesn't parse response as streamingResponse for chunked encoding #213 regression guard)

Verified: with the fix all 3 pass. Without it, test 1 fails with expected "function" Received: "undefined" (data isn't async-iterable). Full suite stays at 5 pre-existing unrelated WebSocket failures (same on main).

Possibly related

#255 / #256 fix non-SSE chunk yield semantics (chunks weren't emitting until end). Both fixes are needed for h2 plain-text streams to work end-to-end client-side, but they address different layers (parsing vs. detection) and don't conflict.

Summary by CodeRabbit

• Bug Fixes

  • Improved HTTP streaming detection for text responses. The library now correctly identifies and handles text responses without explicit Content-Length headers, enabling proper streaming support in HTTP/2 and reverse proxy scenarios.

• Tests

  • Added comprehensive tests validating streaming detection behavior for various text response configurations.

[coderabbitai]

Walkthrough

Relaxes HTTP streaming detection for text/* responses by removing the transfer-encoding: chunked requirement. Non-streaming text responses with Content-Length are still buffered normally; this fix allows HTTP/2 proxies (which strip the chunked header) to properly stream plain-text async generators. ✧

Changes

Cohort / File(s)	Summary
Streaming Detection Logic src/treaty2/index.ts	Removed transfer-encoding: chunked check from text response streaming gate. Now treats any text/* response lacking content-length as streamable, accounting for HTTP/2's prohibition on chunked headers.
Streaming Detection Tests test/treaty2.test.ts	Added comprehensive test suite covering three scenarios: streamed text/plain without Transfer-Encoding (HTTP/2 reverse proxy case), streamed text/plain with chunked header (HTTP/1.1 direct case), and buffered text/plain with explicit Content-Length.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• Fix SSE stream parser with partial chunks (closes #222) #235 — Refactors streamResponse implementation for SSE buffering and chunk handling, which directly consumes the output of the streaming detection gate modified in this PR ♡

Poem

Chunked headers vanish in the h2 haze~
Your streaming text now works through every maze ♡✧
No more hanging, teasing proxy plays!
— Eden finally caught your tricks, how dull… (´•ω•̥`)

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Linked Issues check	✅ Passed	The PR fully addresses issue #258 by removing the Transfer-Encoding: chunked check, adding three comprehensive regression tests, and preserving Content-Length buffering behavior.
Out of Scope Changes check	✅ Passed	All changes in treaty2/index.ts and the test file are directly scoped to the HTTP/2 streaming detection fix; no unrelated modifications are present.
Title check	✅ Passed	The title clearly and specifically summarizes the main change: removing the Transfer-Encoding requirement from text stream detection to support HTTP/2, which is exactly what the changeset accomplishes.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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