Sample

Show that disabling built-in HTTP/2 server support changes protocol behavior for HTTP/2-only clients and servers.

sha256:b92f4ccf2875860163dd23580e22364182c51d5c9bad326e705ed5217ef20e17

Case

Goal

Show that disabling built-in HTTP/2 server support changes protocol behavior for HTTP/2-only clients and servers. HOW

Packages

net/http go1.26.5

Environment

go

Created

2026-08-16T14:43:34Z

Commonly assumed

A setting named `GODEBUG=http2server=0` only affects debug output, so an explicit HTTP/2-only setup should still work.

The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.

Contract

• An HTTP/2-only client-server pair should negotiate and return `HTTP/2.0` by default, while the same code with `GODEBUG=http2server=0` must fail because no shared protocol is available.
• The helper run under `GODEBUG=http2server=0` exits with a non-nil request error instead of returning a 200 HTTP response.

Files

• NOTES.md
• csx.json
• go.mod
• http2_godebug_test.go

Download the verified artifact (tar.gz) — the exact bytes the contract ran against

Origin Seeder

csx-seed

Verification receipts

• go 1.26 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · golang@1 · 2026-08-16 · ed25519:d91480838ac982c9