)

* fix: no panic on empty partition in register_record_batches

`register_record_batches` read the schema via unchecked `partitions.0[0][0]`,
which panics when a partition contains no record batches (e.g. the batches of
an empty pyarrow table, whose `to_batches()` returns `[]`).

Take the schema from the first available batch across all partitions and return
a clear error when there is none, mirroring the empty-table handling added for
`from_arrow_table` in apache#613. A non-empty later partition now also works instead
of panicking on an empty leading one.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* refactor: address review feedback

- Use find_map(|p| p.first()) instead of flatten().next() to make the
  "first batch in any partition" intent clearer (per @kosiew).
- Extend regression test to also assert the empty outer partition list
  case ([]) raises the same ValueError.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* fix: replace rust-toolchain action with rustup commands for toolchain setup

* fix: pin dtolnay/rust-toolchain sha

* pin dtolnay/rust-toolchain sha

* Use allowlisted Rust toolchain action revision

AI Disclosure: This code was written in part by an AI agent.:

* Set rust toolchain so developer and CI get a consistent experience

* minor clippy fixes

…afe credentials (apache#1625)

* Add object_store parameter to register/read file methods

Add an optional object_store parameter to register_parquet, read_parquet,
register_csv, read_csv, register_json, read_json, register_avro, read_avro,
register_arrow, and read_arrow methods.

When provided, the store is automatically registered for the URL scheme
and host parsed from the path, removing the need to manually call
register_object_store separately. This enables thread-safe cloud
credential handling without os.environ mutation.

Includes unit tests (mock-based) for URL parsing logic and integration
tests using LocalFileSystem for end-to-end validation.

Closes apache#1624

* Fix file:// URL handling in _register_object_store_for_path

- Allow empty netloc for file:// scheme (e.g. file:///tmp/data.parquet)
- Require netloc (host/bucket) only for non-file schemes (s3, gs, az, https)
- Add doctest +SKIP to register_parquet example referencing nonexistent file
- Use Path.as_uri() in end-to-end tests for portable file:// URL construction
- Add tests for file:// acceptance and scheme-without-host rejection

* Refactor tests to use pytest.mark.parametrize per reviewer feedback

Replace class-based test structure with flat parametrized functions
to match the repository's testing conventions.

---------

Co-authored-by: Tim Saucer <timsaucer@gmail.com>

* docs: add missing cd step in contributor guide bootstrap

* docs: fix maturin develop flag typo (-uv -> --uv)

This PR tightens the scalar UDF annotations in python/datafusion/user_defined.py:

the callable return type is bounded to pa.Array
the scalar UDF constructor accepts return_field: pa.Field
the decorator form accepts return_field: pa.DataType | pa.Field

Adds datafusion.functions.is_nan(...) as an alias for isnan(...) and adds Expr.is_nan() as the corresponding expression method. Existing isnan() behavior is unchanged.

The PR also adds coverage for both the function-level alias and the expression method.

* Update to main on the upstream datafusion to prepare for DF55 release

* Deprecate singular external table location

AI Disclosure: This code was written in part by an AI agent.:

* Fix tests for updated DataFusion behavior

AI Disclosure: This code was written in part by an AI agent.:

* create table requires a location

* Remove unused Python token from Substrait deserialization

AI Disclosure: This code was written in part by an AI agent.:

* test: cover external table locations binding

AI Disclosure: This code was written in part by an AI agent.:

…1674)

* Bump release candidate version

* spark slice function now respects inner field name