Sample
polars 1.43.2: Identify where Polars LazyFrame plans stop being lazy, which inspection properties emit PerformanceWarning, and how caching and row indexing alter query execution DAGs
Verified sample for pypi polars 1.43.2: Identify where Polars LazyFrame plans stop being lazy, which inspection properties emit PerformanceWarning, and how…
sha256:dadb22ba9a6e892af638971b3f40b0a986b661673c2d361e72209ca677267a96
This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured.
How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people.
MIT-0
Execution evidence
The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.
- Evidence basis
- Signed contract pass
- Verification receipts
- 2
- Signing keys that built it
- 1
Declared environment
python linux x64 python python pip
Verification-run environments
| Environment | Contract | Stages | Run |
|---|---|---|---|
| python 3.12 · linux alpine/x64 · docker ed25519:ac1544ece1e22594 | PASS | compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS CONTAINER_RUN · python@1 |
2026-08-15 |
| python 3.12 · linux alpine/x64 · docker ed25519:d91480838ac982c9 | SKIPPED | compile:SKIPPED · contract:SKIPPED · load:SKIPPED · resolve:FAIL CONTAINER_RUN · python@1 |
2026-08-18 |
Case
HOW- Goal
- Identify where Polars LazyFrame plans stop being lazy, which inspection properties emit PerformanceWarning, and how caching and row indexing alter query execution DAGs
- Packages
- Symbols
-
- polars.LazyFrame
- LazyFrame.collect
- LazyFrame.collect_schema
- LazyFrame.cache
- LazyFrame.explain
- LazyFrame.filter
- LazyFrame.select
- LazyFrame.with_columns
- LazyFrame.with_row_index
- polars.concat
- polars.exceptions.PerformanceWarning
- polars.exceptions.ShapeError
- Environment
- python
- Created
- 2026-08-15T04:33:13Z
Contract
- assert accessing columns, dtypes, schema, or checking membership with in emits PerformanceWarning on LazyFrame
- assert collect_schema() is the zero-warning inspection API providing schema names and dtypes without resolving query plans
- assert LazyFrame indexing by integer or string and len() or bool() raise TypeError, while slice indexing returns an unexecuted LazyFrame
- assert multi-consumer DAGs recompute upstream nodes for each branch unless explicitly cached with .cache()
- assert .cache() materializes the node once in memory and blocks downstream filter pushdown from penetrating upstream
- assert with_row_index acts as an optimization barrier that prevents subsequent filter expressions from being pushed down
- assert concat on LazyFrames with mismatched column schemas builds and inspects without error and raises ShapeError only on collect
- assert collect(background=True) returns an InProcessQuery handle whose fetch_blocking() retrieves the materialized DataFrame
Files
- NOTES.md
- csx.json
- requirements.txt
- src/__init__.py
- src/lazy_ops.py
- test/contract.py