fix: plan aggregates over CASE conditions with multiple columns

[1fanwang]

Which issue does this PR close?

Closes #25369

Rationale for this change

Aggregates over a repeated CASE expression can fail during planning when its condition refers to multiple columns. The reported SUM query now returns 1 instead of an internal schema error.

What changes are included in this PR?

Physical CASE nullability uses the existing three-valued bounds for AND, OR and NOT when a condition cannot be evaluated without input rows. The aggregate's schema check stays unchanged.

The non-nullability deduction relies on NULL AND x never being true, for any x, including NULL. OR and NOT must preserve the distinction between false and NULL; the regression tests cover both nullable and non-nullable branches.

What is the testing strategy for this PR?

The SQL regression exercises SUM, COUNT, expanded BETWEEN, NULL inputs, nullable or missing ELSE, and empty input. Parameterized unit tests cover both operand orders. The physical-expression tests also check Boolean-cast failures in literal conditions, both AND/OR operands and NOT, through nullability inference and evaluation.

On macOS arm64 with Rust 1.98.1 and the pinned test data:

cargo test --locked --profile ci -j6 -p datafusion-physical-expr -p datafusion-expr -p datafusion-optimizer --lib
cargo test --locked --profile ci -j6 -p datafusion-sqllogictest --test sqllogictests -- --test-threads 6 cse.slt case.slt aggregate.slt

Raw logs

Before:

Internal error: Physical input schema should be the same as the one converted from logical input schema. Differences:
	- field nullability at index 0 [__common_expr_1]: (physical) true vs (logical) false.
Error: Execution("1 failures")

After:

Progress: 5/5 files completed (100%)
slt_exit_code=0

Are there any user-facing changes?

The affected aggregate queries plan and run. There is no public API change.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.80%. Comparing base (0d79252) to head (53077d2).

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #25684   +/-   ##
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  Coverage   82.80%   82.80%           
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  Files        1149     1149           
  Lines      454146   454153    +7     
  Branches   454146   454153    +7     
=======================================
+ Hits       376035   376054   +19     
+ Misses      55260    55254    -6     
+ Partials    22851    22845    -6     

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[kosiew]

@1fanwang,

Thanks for the fix! The three-valued bounds handling addresses the reported CASE nullability issue, and the regression coverage looks good. I have one optional suggestion for additional test coverage. This is not a blocker.

[kosiew]

Could we also test mixed AND/OR recursion with CASE WHEN a > 1 AND (b < 3 OR b IS NULL) THEN a ELSE 0 END and its negated form? The first should be non-nullable, while the second is nullable because a = NULL, b = 3 makes the negated condition TRUE. This would cover nested operators beyond the current tests. Not a blocker.