…-config

Use new polars engine config object in cudf-polars callback

## Description
<!-- Provide a standalone description of changes in this PR. -->
<!-- Reference any issues closed by this PR with "closes rapidsai#1234". -->
<!-- Note: The pull request title will be included in the CHANGELOG. -->

Adapts to IR changes in polars 1.4 and handles nrows/skiprows a little
more correctly.

## Checklist
- [ ] I am familiar with the [Contributing
Guidelines](https://github.com/rapidsai/cudf/blob/HEAD/CONTRIBUTING.md).
- [ ] New or existing tests cover these changes.
- [ ] The documentation is up to date with these changes.

---------

Co-authored-by: Lawrence Mitchell <[email protected]>

Add support for ``pl.col.str.replace`` and ``pl.col.str.replace_many``

Authors:
  - Thomas Li (https://github.com/lithomas1)

Approvers: None

URL: rapidsai#16039

…sts (rapidsai#16441) (rapidsai#16605)

Authors:
  - Thomas Li (https://github.com/lithomas1)
  - https://github.com/brandon-b-miller

Approvers:
  - Vyas Ramasubramani (https://github.com/vyasr)

URL: rapidsai#16605

…ai#16509)

contributes to rapidsai#16478

This implements "cum_min", "cum_max", "cum_prod", "cum_sum"

"cum_count" is not implemented for now, since there's no exact libcudf match (I imagine the non-grouped case is also not used that much but haven't checked).
I suppose we could implement it by creating a column of 1s and copying the null mask over, and doing a cum_sum on that.
Let me know if you want to try that.

Authors:
  - Thomas Li (https://github.com/lithomas1)

Approvers:
  - https://github.com/brandon-b-miller

URL: rapidsai#16509

…olumn

Use a key column rather than a placeholder for count agg

## Description

- Closes rapidsai#16477

…16596)

polars.from_arrow renames empty column names (see
pola-rs/polars#11632). This causes problems
when round-tripping specially crafted dataframes. Avoid the problem by
constructing the table with fake names and then renaming.

Add support for additional unaryops through `cudf-polars`. 

Closes rapidsai#16566

---------

Co-authored-by: Lawrence Mitchell <[email protected]>

Forward-merge 24.08

Add support for string `strip` in `pylibcudf` and `cudf-polars`.

---------

Co-authored-by: Lawrence Mitchell <[email protected]>

This PR adds datetime/timestamp parsing from string columns in pylibcudf
and cudf-polars.

Closes rapidsai#16174

Support `pl.Expr.quantile` in cudf-polars.

---------

Co-authored-by: Vyas Ramasubramani <[email protected]>

Since the full-frame `Agg` handler for first and last doesn't construct
a request (because we can do it without a `from_scalar` call), we didn't
handle these in a groupby context. Fortunately it is easy to add.

We were previously not calling the superclass __post_init__ in custom
validations of IR nodes. This meant that we would sometimes fail to
raise when the schema contained an EMPTY column.

Since we can't really compute with these types, we just fall back.

To do this we need to inspect the polars datatypes, since by the time
we've converted to the pylibcudf one, the nested element types have
been lost.

We don't do this eagerly during dtype conversion because we still want
to allow scalar literals with null dtype that will then be cast to a
non-null dtype.

This way if we don't support any features of the pattern, we correctly
fall back to CPU.

…-invalid-regex

Move creation of regex program to initialisation

…ty-columns

Disallow producing dataframes with Empty columns

We are not yet exposing the actual information that the groupby is dynamic, but this catches a bunch of cases.

Authors:
  - Lawrence Mitchell (https://github.com/wence-)

Approvers:
  - Vyas Ramasubramani (https://github.com/vyasr)

URL: rapidsai#16720

…sai#16476)

We previously didn't support this case correctly, but it's not too bad.

This would be much easier if we could do it in libcudf, hence:
rapidsai#16475

Correctly handle `pow` and `log` by translating to binary expressions
when we observe the node.

Upgrade our minimum supported polars version (so that we see all these
function names from the rust IR).

Also tighten check for which groupby-aggs are supported when the
expression contains a unary function.

Add support for unpivoting a DataFrame. We raise for cases where the
concatenation of the value columns produces a cast that is not supported
by standard fixed-width unary casting.

Reject two more edge cases that we do not support.

We could easily support the case where the parquet read just needs to
read the metadata, but it is low priority, so have not done so here.

---------

Co-authored-by: brandon-b-miller <[email protected]>
Co-authored-by: Bradley Dice <[email protected]>
Co-authored-by: Lawrence Mitchell <[email protected]>

…ai#16755)

This field renaming was due to a recent refactor in (as-yet-unreleased)
polars 1.7.

## Description

We implement a small pytest plugin that defaults the polars engine to
GPU (by monkeypatching `LazyFrame.collect`, yet another reason to have a
global default somehow).

As well as this, we collate all the known failures and classify them.


## Checklist
- [x] I am familiar with the [Contributing
Guidelines](https://github.com/rapidsai/cudf/blob/HEAD/CONTRIBUTING.md).
- [x] New or existing tests cover these changes.
- [x] The documentation is up to date with these changes.