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Avoid reallocating singleton call arguments - #26223
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Memory usage reportMemory usage unchanged ✅ |
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Merging this PR will improve performance by 4.43%
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| Mode | Benchmark | BASE |
HEAD |
Efficiency | |
|---|---|---|---|---|---|
| ⚡ | Simulation | parser[pydantic/types.py] |
1.5 ms | 1.4 ms | +4.43% |
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Comparing micha/avoid-single-call-argument-reallocation (56bf0b5) with main (c975881)
Footnotes
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4 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. ↩
MichaReiser
commented
Jun 22, 2026
| let start = self.node_start(); | ||
| self.bump(TokenKind::Lpar); | ||
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| if self.eat(TokenKind::Rpar) { |
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This helped mitigate what otherwise was a perf regression
MichaReiser
added
performance
MichaReiser
marked this pull request as ready for review
June 22, 2026 13:59
charliermarsh
approved these changes
Jun 22, 2026
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Summary
Reserve exactly one positional-argument slot when a call's first argument is immediately followed by
), avoiding the usual capacity-four allocation and boxed-slice shrink. Singletons are 63.48% of calls with positional arguments across ty's 162-project ecosystem corpus, while multi-argument calls retain their existing allocation path.Test Plan
Testing: Ran the parser test suite, Clippy, and repository hooks.