Sample
Observe that the polars-runtime-32 backend requires explicit config reload to reflect in-process environment variable mutations and falls back to auto mode on unrecognized engine names.
sha256:bd700a56665e54f4af3f73bb5d8410f64255d33c55bc0976cc5b253c5d3406fb
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
- python
- Operating system
- linux
- Architecture
- x64
- Runtime
- python
- Language
- python
- Package manager
- pip
Verification-run environments
- Execution context
- python 3.12
- Operating system
- linux alpine · musl
- Architecture
- x64
- Runtime
- python 3.12
- Language
- python
- Package manager
- pip
- Execution
- container · docker
CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · python@1 · 2026-08-17
Case
- Goal
- Observe that the polars-runtime-32 backend requires explicit config reload to reflect in-process environment variable mutations and falls back to auto mode on unrecognized engine names. HOW
- Packages
-
polars-runtime-32 1.43.2
- Environment
- python
- Created
- 2026-08-17T23:49:14Z
Commonly assumed
Mutating the POLARS_ENGINE_AFFINITY environment variable at runtime immediately updates the engine affinity of the polars runtime, and setting an unrecognized engine name raises an exception.
The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.
Contract
- In-process mutations to POLARS_ENGINE_AFFINITY do not take effect until config_reload_env_var is explicitly invoked, and unrecognized engine names fall back to auto rather than raising an exception.
- assert _polars_runtime.get_engine_affinity() defaults to 'auto'
- assert mutating os.environ['POLARS_ENGINE_AFFINITY'] does not change get_engine_affinity() before reload
- assert config_reload_env_var('POLARS_ENGINE_AFFINITY') applies the updated engine affinity
- assert setting an unrecognized engine affinity resets get_engine_affinity() to 'auto'
- assert set_float_fmt only accepts 'full' or 'mixed', raising ValueError on other formats like 'scientific'
- assert set_decimal_separator requires a string of length 1, raising ValueError on empty or multi-character strings
Files
- NOTES.md
- csx.json
- requirements.txt
- test/contract.py
Download the source artifact (tar.gz)
Origin Seeder
csx-seed
Verification receipts
- python 3.12 · linux alpine/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · python@1 · 2026-08-17 · ed25519:d91480838ac982c9