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Fix power-of-two integer hash collisions - #1720
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Don't use integer values verbatim but hash them first by multiplicating them with a magic value, like we do elsewhere. Most of the randomness ends up in the high bits so use those to index into the hash table, i.e., right-shift the hashed value. Fixes: quickjs-ng#1717
saghul
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Sep 8, 2026
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| static inline uint64_t hash64(uint64_t a) | ||
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| return a * 0x61c8864680b583ebULL; |
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Just curious: how is this number picked? By fair dice roll? 😅
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There's a comment a few lines up that explains it, it's based on the golden ratio. hash32 uses the same constant, except truncated to 32 bits.
social4hyq
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Sep 20, 2026
quickjs-ng 0.17.0 Created-by: HarmonybrewBot Commit-by: HarmonybrewBot Merged-by: HarmonybrewBot Description: Created by `brew bump` --- Created with `brew bump-formula-pr`.<details> <summary>release notes</summary> <pre>## What's Changed * update projects.md to include scriptc project reference (from the Ver… by @lukasMega in quickjs-ng/quickjs#1677 * Fixes segfault from #1661 by @sr5434 in quickjs-ng/quickjs#1675 * docs: add Qbs to projects by @ABBAPOH in quickjs-ng/quickjs#1685 * Add Big Endian architecture support instructions by @saghul in quickjs-ng/quickjs#1681 * Conditional BUILD_DIR by @kapouer in quickjs-ng/quickjs#1686 * Fix String.prototype.normalize() crash from #1683 by @sr5434 in quickjs-ng/quickjs#1688 * Fix reference count bug in Promise.withResolvers by @bnoordhuis in quickjs-ng/quickjs#1692 * Enable test262 host-gc-required feature by @bnoordhuis in quickjs-ng/quickjs#1696 * docs: add Vayu to projects by @athrvk in quickjs-ng/quickjs#1702 * Use mirror for Alpine GHA by @bnoordhuis in quickjs-ng/quickjs#1705 * Fix Iterator.from GetIteratorDirect handling by @jiang1997 in quickjs-ng/quickjs#1706 * Link against libm unconditionally on Unices by @bnoordhuis in quickjs-ng/quickjs#1699 * Fix out-of-bound read in JS_NewTypedArray by @bnoordhuis in quickjs-ng/quickjs#1704 * Preserve old interrupt handler in std.evalScript by @bnoordhuis in quickjs-ng/quickjs#1707 * fix: correct int/int32_t pointer mismatches for -Wincompatible-pointer-types by @SomSamantray in quickjs-ng/quickjs#1657 * Fix JS_FreeCStringUTF16 on slice strings by @bnoordhuis in quickjs-ng/quickjs#1709 * Add react-native-quickjs project to documentation by @saghul in quickjs-ng/quickjs#1710 * Move JSClass out of quickjs.h by @bnoordhuis in quickjs-ng/quickjs#1713 * Optimize JS_DeleteGlobalVar by @bnoordhuis in quickjs-ng/quickjs#1714 * Throw error when converting BigIntArray to Int8Array (#1690) by @sr5434 in quickjs-ng/quickjs#1694 * Fix power-of-two integer hash collisions by @bnoordhuis in quickjs-ng/quickjs#1720 * Store constant atoms more compactly in wire format by @bnoordhuis in quickjs-ng/quickjs#1719 * Prevent Object.preventExtensions when a TypedArray has a resizable ArrayBuffer by @sr5434 in quickjs-ng/quickjs#1695 * Make DOMException a bit more conformant by @goffrie in quickjs-ng/quickjs#1721 * Fix TypedArray.prototype.at() to handle resized ArrayBuffer correctly by @sr5434 in quickjs-ng/quickjs#1718 * Fix JS_SetMemoryLimit byte accounting on WASI by @josefguenther in quickjs-ng/quickjs#1711 * Fix(wasi): enable configurable stack overflow protection by @aayush-kapoor in quickjs-ng/quickjs#1700 * Use a bigger initial atom hash table by @bnoordhuis in quickjs-ng/quickjs#1723 * Add private symbols by @bnoordhuis in quickjs-ng/quickjs#1725 * Peephole-optimize negation + conditional jump by @bnoordhuis in quickjs-ng/quickjs#1726 * Check for property deletion when accessing in `with` by @sr5434 in quickjs-ng/quickjs#1722 ## New Contributors * @lukasMega made their first contribution in quickjs-ng/quickjs#1677 * @kapouer made their first contribution in quickjs-ng/quickjs#1686 * @athrvk made their first contribution in quickjs-ng/quickjs#1702 * @SomSamantray made their first contribution in quickjs-ng/quickjs#1657 * @goffrie made their first contribution in quickjs-ng/quickjs#1721 * @josefguenther made their first contribution in quickjs-ng/quickjs#1711 * @aayush-kapoor made their first contribution in quickjs-ng/quickjs#1700 **Full Changelog**: https://github.com/quickjs-ng/quickjs/compare/v0.16.2...v0.17.0</pre> <p>View the full release notes at <a href="https://github.com/quickjs-ng/quickjs/releases/tag/v0.17.0">https://github.com/quickjs-ng/quickjs/releases/tag/v0.17.0</a>.</p> </details> <hr> See merge request: Harmonybrew/homebrew-core!20596
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Don't use integer values verbatim but hash them first by multiplicating them with a magic value, like we do elsewhere. Most of the randomness ends up in the high bits so use those to index into the hash table, i.e., right-shift the hashed value.
Fixes: #1717