Trouble with Polars input
2 posts from 2 people2d activeSteady, +1 this weekunverified
Posts per day
The posts behind it
Plugin built with `#[polars_expr(output_type=...)]` aborts the process on an input dtype its polars build lacks
...265 of 293 `#[polars_expr]` uses). As far as I could tell, from the plugin side there is no way to guard this, since the panic happens before any user code runs. > [!NOTE] > The current workaround is to enable every dtype feature on the plugin's `polars` dependency...
`diff(n, null_behavior="drop")` panics when the input is shorter than `n`
### Checks - [x] I have checked that this issue has not already been reported. - [x] I have confirmed this bug exists on the [latest version](https://pypi.org/project/polars/) of Polars. ### Reproducible example The bug does not only show up with lists directly either: ### Log...
Companies and products named
About this problem
Evidence
2 posts from 2 people in 1 place, about 1 a week over 34 days. Mostly on pola-rs/polars. Tools named alongside: PyPI.
Frustration Frustration 0 of 3· Seen on GitHub issues
How it was grouped
Posts about Polars with no known issue, sharing the word "input". First post Oct 5, 2026, latest Nov 7, 2026. Unverified: fewer than 3 posts, or one person or place only. Method
Other Polars problems
Trouble with Polars group
Top post: "Datetime out-of-range in `group_by_dynamic` streaming engine", one of 10 posts from 7 people on GitHub issues.
Trouble with Polars join
Top post: "Coalescing full join on Int32-vs-Int64 keys with `unique` incorrect", one of 8 posts from 8 people on GitHub issues.
Polars upgrades break working setups
24 posts from 17 people on GitHub issues.
Trouble with Polars column
Top post: "Compare lists in one column to the first n elements of another column in Python Polars lazyframes, where n is", one of 21 posts from 16 people on GitHub issues, Stack Overflow.
Polars users keep filing bugs
Top post: "Consider upgrading the brotli crate (CVE-2026-111497)", one of 20 posts from 14 people on GitHub issues.
Trouble with Polars parquet
Top post: "`is_in` with more than 100 values does not skip Parquet row groups between the values", one of 7 posts from 7 people on GitHub issues.
Trouble with Polars cache
Top post: "Predicate pushdown into a shared cache applies a filter below each branch's slice", one of 5 posts from 4 people on GitHub issues.
Trouble with Polars streaming
Top post: "`min_by`/`max_by`/`sort_by` with a scalar `by`: in-memory engine raises, streaming broadcasts", one of 5 posts from 3 people on GitHub issues.
Trouble with Polars instead
Top post: "Series.to_list() panics on out-of-range datetimes instead of raising an error", one of 5 posts from 5 people on GitHub issues.
Trouble with Polars iceberg
Top post: "`sink_iceberg` ignores catalog credentials", one of 5 posts from 3 people on GitHub issues.
Bad data slips through Polars unnoticed
4 posts from 4 people on GitHub issues, Reddit.
Trouble with Polars value
Top post: "polars.read_excel() value error on very large date", one of 4 posts from 4 people on GitHub issues.
History