[robert3005]

Slicing or filtering a DictArray whose codes are a constant valid code rebuilt the dict with non-nullable 0u8 codes. With nullable codes over non-nullable values this narrowed the dtype (e.g. bool? -> bool), which the optimizer rejects as a reduce-rule dtype mismatch.

Fixes #10764

[codspeed]

Merging this PR will degrade performance by 25.89%

2 warnings, 1 note

⚠️ Walltime results may be unreliable

Some benchmarks used the Walltime instrument outside CodSpeed Macro Runners, which can make the results inconsistent.

Learn more about Macro Runners

See affected benchmarks

⚠️ 63 benchmarks are dominated by system calls

System calls cannot be simulated consistently and are left out of the measure. The reported value understates the real cost. Switch to the Walltime instrument to measure them.

Learn more about system calls

See affected benchmarks

ℹ️ 40 benchmarks have no flamegraph

The flamegraph wasn't generated: the symbols of the profiling trace could not be resolved, because no information about the language frames was collected.

See affected benchmarks

⚡ 2 improved benchmarks
❌ 6 regressed benchmarks
✅ 2400 untouched benchmarks
⏩ 12 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Walltime	filter_neon[8]	915 ns	1,957 ns	-53.24%
❌	Walltime	threshold_neon[8]	1.4 µs	2.8 µs	-51.6%
❌	Walltime	filter_neon[64]	1.8 µs	3.2 µs	-45.42%
❌	Walltime	threshold_neon[64]	2.6 µs	4 µs	-33.52%
❌	Walltime	threshold_neon[80]	3.6 µs	5 µs	-28.8%
❌	Walltime	filter_neon[80]	2.5 µs	3.3 µs	-23.86%
⚡	CPU Simulation	take_map[(0.01, 0.05)]	1,570.7 ns	871.4 ns	+80.24%
⚡	Walltime	bitpack_blocked_compress_avx2	7.6 µs	6.7 µs	+13.41%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing claude/nifty-pasteur-rhotkn (c7ffd98) with develop (1dba73c)}

Footnotes

1. 12 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[mhk197]

lgtm