lib: fix evenRound sign for fractional values in (-1, 1)#62837
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lib: fix evenRound sign for fractional values in (-1, 1)#62837deepview-autofix wants to merge 1 commit intonodejs:mainnodejs/node:mainfrom deepview-autofix:deepview/500aa18f3bdeepview-autofix/node:deepview/500aa18f3bCopy head branch name to clipboard
evenRound sign for fractional values in (-1, 1)#62837deepview-autofix wants to merge 1 commit into
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`evenRound` derived the rounding direction from `MathSign(i)` where `i = integerPart(x)`. For any `x` whose truncated integer part is zero (e.g. `0.7`, `-0.7`), `sign` was `0`, so the non-halfway branch returned `i + sign === 0` instead of rounding away from zero. This produced incorrect `[Clamp]` WebIDL integer conversions for fractional inputs in `(-1, 0) ∪ (0, 1)` that are not exactly `±0.5`, observable e.g. via `new Blob([Uint8Array.of(1,2,3)]).slice(-0.9999999)` returning the whole blob instead of a 1-byte slice. Use `MathSign(x)` so the rounding direction follows the sign of the original value. Co-Authored-By: Claude <noreply@anthropic.com> Co-Authored-By: DeepView Autofix <276251120+deepview-autofix@users.noreply.github.com> Co-Authored-By: Nikita Skovoroda <chalkerx@gmail.com> Signed-off-by: Nikita Skovoroda <chalkerx@gmail.com>
ChALkeR
reviewed
Apr 20, 2026
Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #62837 +/- ##
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Coverage 89.62% 89.62%
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Files 706 706
Lines 219136 219136
Branches 41987 41981 -6
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+ Hits 196404 196410 +6
- Misses 14611 14614 +3
+ Partials 8121 8112 -9
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ljharb
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Apr 20, 2026
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Closing in favor of #62979 |
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evenRoundderived the rounding direction fromMathSign(i)wherei = integerPart(x). For anyxwhose truncated integer part is zero (e.g.0.7,-0.7),signwas0, so the non-halfway branch returnedi + sign === 0instead of rounding away from zero.This produced incorrect
[Clamp]WebIDL integer conversions for fractional inputs in(-1, 0) ∪ (0, 1)that are not exactly±0.5Observable e.g. via
new Blob([Uint8Array.of(1,2,3)]).slice(-0.9999999)returning the whole blob instead of a 1-byte slice.Use
MathSign(x)so the rounding direction follows the sign of the original value.