fix: handle empty tables in get_add_actions()

[vsmanish1772]

Description

This PR fixes a panic that occurs when get_add_actions() is called on a Delta table that has no add actions (i.e., no data files).

Problem

When calling get_add_actions() on a table with no files, the function panics with:

index out of bounds: the len is 0 but the index is 0

This happens because the code attempts to access results[0] without checking if the results vector is empty.

Solution

• Added early return check for empty files before creating the evaluator
• When files are empty, create an empty RecordBatch with the correct schema
• This matches the behavior from version 1.1.4 where empty tables were handled gracefully

Changes

• Check if files are empty before processing
• Return empty RecordBatch with correct schema when no files exist

Testing

• Added unit test that covers the empty table scenario
• Test verifies both flattened and non-flattened schemas

Fixes #3918

[github-actions]

ACTION NEEDED

delta-rs follows the Conventional Commits specification for release automation.

The PR title and description are used as the merge commit message. Please update your PR title and description to match the specification.

[codecov]

Codecov Report

❌ Patch coverage is 69.23077% with 8 lines in your changes missing coverage. Please review.
✅ Project coverage is 74.17%. Comparing base (5575ad1) to head (c5a285f).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/core/src/table/state.rs	69.23%	4 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3922      +/-   ##
==========================================
- Coverage   74.19%   74.17%   -0.02%     
==========================================
  Files         152      152              
  Lines       39552    39554       +2     
  Branches    39552    39554       +2     
==========================================
- Hits        29346    29340       -6     
- Misses       8879     8885       +6     
- Partials     1327     1329       +2     

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[vsmanish1772]

can someone look into this please? The build complains about formatting but locally it doesnt throw that error

[rtyler]

@vsmanish1772 what version of Rust are you building with? CI runs with 1.91 or whatever is stable, but I see the issues with 1.90 as well

[vsmanish1772]

@vsmanish1772 what version of Rust are you building with? CI runs with 1.91 or whatever is stable, but I see the issues with 1.90 as well

@rtyler I'm using rustc 1.91.0 (f8297e351 2025-10-28)