perf: Element-wise comparison only for tolerance-requiring data types

[Marius Merkle (MariusMerkleQC)]

Motivation

See this comment.

Changes

Introduce a function _needs_element_wise_comparison that checks whether element-wise comparison needs to be performed; this is the case for

(1) float vs numeric columns -> absolute and relative tolerances apply (-> _is_float_numeric_pair())
(2) temporal columns -> absolute temporal tolerance applies (-> _is_temporal_pair())
(3) Different enums
(4) Enum vs categorical comparison

In all other cases, naive comparison suffices, and this shortcut is taken if the above helper returns False. This avoids the expensive _compare_sequence_columns(). The performance improvement can be seen in the benchmark test.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (ff8439c) to head (8dfe919).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

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  Coverage   100.00%   100.00%           
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  Files           10        10           
  Lines          758       776   +18     
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+ Hits           758       776   +18     

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[Copilot]

Pull request overview

This PR optimizes condition_equal_columns for nested list/array columns by avoiding the expensive element-wise comparison path when tolerances/special handling aren’t needed, and updates the performance benchmark accordingly.

Changes:

• Add _needs_element_wise_comparison() (plus helpers) to decide when list/array columns require element-wise comparison.
• Shortcut list/array comparisons to eq_missing() when element-wise handling is deemed unnecessary.
• Update the performance test to assert comparable performance for list<i64> comparisons.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
diffly/_conditions.py	Introduces dtype-based gating to skip element-wise list/array comparisons unless tolerances/special handling are needed.
tests/test_performance.py	Updates benchmark expectations to ensure the optimized path is not significantly slower than direct eq_missing().

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[Oliver Borchert (borchero)]

Nice, thanks