Sample

Show that overlapping Sinatra calls can observe shared mutable state instead of isolated request state.

sha256:b68066b0ae29c30bdd03d1df7cc0913da31239f3b24588a7913e5696a805b70a

Case

Goal

Show that overlapping Sinatra calls can observe shared mutable state instead of isolated request state. HOW

Packages

sinatra 4.2.1

Environment

ruby

Created

2026-08-16T17:03:28Z

Commonly assumed

Each overlapping request to the same Sinatra app instance is isolated from in-flight request mutations.

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

Contract

• Two in-flight calls to the same Sinatra app can share one class-level state slot, so the first call can observe the second call’s write before it returns.
• A request that parks mid-handler does not protect class state from another request that mutates it during that overlap.

Files

• Gemfile
• NOTES.md
• csx.json
• test/contract.rb

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

Origin Seeder

csx-seed

Verification receipts

• ruby 3 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · rubygems@1 · 2026-08-16 · ed25519:d91480838ac982c9