Sample
Compose request URLs, path parameters, query params, and body steps in Req without network side effects
sha256:44ed518e27a03b5bcb2248c4e2644a12adf18d5288dd063d62acf4e74a458ee0
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
- elixir
- Operating system
- linux
- Architecture
- x64
- Runtime
- elixir
- Language
- elixir
- Package manager
- mix
Verification-run environments
- Execution context
- elixir 1
- Operating system
- linux alpine · musl
- Architecture
- x64
- Runtime
- elixir 1
- Language
- elixir
- Package manager
- mix
- Execution
- container · docker
CONTAINER_RUN · compile:PASS · contract:PASS · load:PASS · resolve:PASS · hex@1 · 2026-08-17
Case
- Goal
- Compose request URLs, path parameters, query params, and body steps in Req without network side effects HOW
- Packages
-
req 0.7.2
- Environment
- elixir
- Created
- 2026-08-17T04:45:26Z
Commonly assumed
Merging a leading-slash path into a base_url in Req replaces the base path following RFC 3986, and setting a body on a default request sends a GET request.
The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.
Contract
- assert Req.Steps.put_base_url concatenates leading-slash paths to the base_url path instead of replacing it like RFC 3986 URI.merge
- assert put_base_url evaluates dynamic 0-arity base_url functions and ignores base_url entirely when the request URL has an explicit scheme
- assert Req.Steps.encode_body automatically changes request method from :get to :post when body, json, or form is set, but preserves explicit methods like :put
- assert Req.Steps.put_path_params URI-encodes values in :colon template style, preserves known unmapped placeholders literally, and raises on uninterned placeholders
- assert Req.Steps.put_params decodes existing URL query strings and updates matched keys in place via keystore rather than appending duplicate keys
- assert Req validates options against registered keys raising ArgumentError on unregistered options, and a request step returning {req, resp} short-circuits the pipeline
Files
- NOTES.md
- csx.json
- mix.exs
- mix.lock
- test/contract_test.exs
- test/test_helper.exs
Download the source artifact (tar.gz)
Origin Seeder
csx-seed
Verification receipts
- elixir 1 · linux alpine/x64 · docker · CONTAINER_RUN · compile:PASS · contract:PASS · load:PASS · resolve:PASS · hex@1 · 2026-08-17 · ed25519:d91480838ac982c9