Sample
Handle Rack::Test header HTTP_ double-prefixing, 308 redirect method mutation, query array flattening, and cookie comma truncation
sha256:6aecd2e6d9ef6825e6ce4c57fc426ae63e441fa97f883f1d312c633d86a88d25
PUBLISHED
L3_CONTRACT_PASS
MIT-0
Case
- Goal
- Handle Rack::Test header HTTP_ double-prefixing, 308 redirect method mutation, query array flattening, and cookie comma truncation HOW
- Packages
- rack-test 2.2.0 rack 3.2.7
- Environment
- ruby
- Created
- 2026-08-16T16:46:17Z
Commonly assumed
Calling header with a header name already starting with HTTP_ sets the Rack environment key directly, and follow_redirect! preserves request method and body on 308 Permanent Redirect identically to 307.
The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.
Contract
- Rack::Test::Session#header unconditionally prepends HTTP_ to all header names other than CONTENT_TYPE and CONTENT_LENGTH, mangling HTTP_AUTHORIZATION into HTTP_HTTP_AUTHORIZATION, while follow_redirect! hardcodes a check only for 307 and mutates 308 Permanent Redirect requests to GET while dropping parameters.
- Passing nil in GET params encodes as a bare key parsed back as nil, empty string encodes as key= parsed as empty string, empty array encodes as key[]= parsed as [""], and nested 2D arrays are flattened into a 1D query string
- In multipart POST requests, nil parameters are coerced to empty strings in form parts and empty arrays produce no parts at all, omitting the key from parsed parameters
- Rack::Test::Cookie splits Set-Cookie headers on commas, truncating cookie values containing commas at the first comma, and scopes paths using start_with? matching prefixes beyond directory boundaries
Files
- Gemfile
- Gemfile.lock
- NOTES.md
- csx.json
- src/app.rb
- test/contract.rb
Download the verified artifact (tar.gz) — the exact bytes the contract ran against
Origin Seeder
Verification receipts
- ruby 3 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · rubygems@1 · 2026-08-16 · ed25519:d91480838ac982c9