Sample

middleware.Timeout requires cooperative ctx.Done() handling and emits 504 Gateway Timeout only when no response header or body has been written.

sha256:d703cfb3d5b1eaad2e92796d4abaacac8b1654ccfc81a32a61628602e17a6b57

PUBLISHED L3_CONTRACT_PASS MIT-0

Execution evidence

Declared environment and signed verification runs are separated so you can see exactly what this sample proves.

Evidence basisSigned contract pass

Verification receipts1

Verification levelL3_CONTRACT_PASS

Declared environment

Execution context: go
Operating system: linux
Architecture: x64
Runtime: go
Language: go
Package manager: go

Verification-run environments

Execution context: go 1.26
Operating system: linux alpine · musl
Architecture: x64
Runtime: go 1.26
Language: go
Package manager: go
Execution: container · docker

CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · golang@1 · 2026-08-17

Case

Goal: middleware.Timeout requires cooperative ctx.Done() handling and emits 504 Gateway Timeout only when no response header or body has been written. HOW
Packages: github.com/go-chi/chi/v5 5.3.1
Environment: go
Created: 2026-08-17T07:26:05Z

Commonly assumed

middleware.Timeout enforces a hard wall-clock timeout by asynchronously aborting the handler and returning 504 Gateway Timeout even if the handler blocks or writes data.

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

Contract

When a handler cooperatively returns upon ctx.Done() without writing to ResponseWriter, middleware.Timeout writes HTTP 504 StatusGatewayTimeout with an empty body.
When a handler blocks synchronously without selecting on ctx.Done(), middleware.Timeout does not interrupt execution early and blocks the client until the handler finishes.
When a handler writes headers or body before or during context expiration, middleware.Timeout cannot override the response and the client receives the handler's committed status code rather than 504.
When a fast handler completes within the timeout, middleware.Timeout does not interfere and the client receives the handler's response.
When a request context is canceled without exceeding its deadline, middleware.Timeout does not write HTTP 504.

Files

NOTES.md
csx.json
go.mod
go.sum
timeout_test.go

Download the source artifact (tar.gz)

Origin Seeder

csx-seed

Verification receipts

go 1.26 · linux alpine/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · golang@1 · 2026-08-17 · ed25519:d91480838ac982c9