index out of bounds: the len is 2 but the index is 2 in some data sources

[alamb]

Describe the bug

As part of testing DataFusion 46.0.0 on Delta.rs in

• chore: upgrade to DataFusion 46.0.0 delta-io/delta-rs#3261

Here is an example failure:

https://github.com/delta-io/delta-rs/actions/runs/13592071811/job/38008047004?pr=3261

FAILED tests/test_cdf.py::test_read_cdf_partitioned_projection - pyo3_runtime.PanicException: index out of bounds: the len is 3 but the index is 3
FAILED tests/test_cdf.py::test_read_cdf_last_version - pyo3_runtime.PanicException: index out of bounds: the len is 2 but the index is 2
==== 2 failed, 495 passed, 7 skipped, 35 deselected, 95 warnings in 40.15s =====

To Reproduce

As @blaginin noted on delta-io/delta-rs#3261 (comment) the way to reproduce this is (in delta-rs)

cd python
make develop
RUST_BACKTRACE=1 uv run pytest tests/test_cdf.py -s -k "test_read_cdf_partitioned_projection"

Expected behavior

Tests should passs

Additional context

• We had simmilar issues elsewhere Error projecting statistics in DataSourceExec #14905
• This is probably some more fallotu from Introduce unified DataSourceExec for provided datasources, remove ParquetExec, CsvExec, etc #14224

[alamb]

@blaginin has a proposed fix for this:

• Do not swap with projection when file is partitioned #14956

❤