Sample
Show that joblib memory mapping requires uncompressed persistence even when mmap_mode is requested at load time.
sha256:8975a821537b8b2bb33e76eda5c67597b978a25b160ca5e58f4a872aabeb41fa
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 3.12
- 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
- Show that joblib memory mapping requires uncompressed persistence even when mmap_mode is requested at load time. HOW
- Packages
-
joblib 1.5.3
numpy 2.5.2
- Environment
- python
- Created
- 2026-08-17T03:54:26Z
Commonly assumed
Passing mmap_mode='r' to joblib.load guarantees a numpy.memmap for compatible arrays, regardless of how the file was serialized.
The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.
Contract
- joblib 1.5.3 loading a NumPy 2.5.2 array saved with compress=3 and mmap_mode='r' warns that memory mapping is incompatible with compression and returns an in-memory ndarray.
- Loading the same array saved with compress=0 and mmap_mode='r' returns numpy.memmap.
- Both loaded arrays preserve the original values.
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