Fix for recent Nim JS changes: swizzle setters read before they write - #92
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Nim 2.2.12's JS backend no longer copies an object for `let b = b`, so the object based layout aliased source and destination in swizzle setters and `b.wzyx = b` clobbered its own input. The generator now reads every component into a scalar before assigning, which cannot alias on any backend or layout. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
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Summary
CI on master fails the "vec4 swizzle self-assignment" test in the JavaScript object based layout since
treeform/setup-nim-action@v6moved to Nim 2.2.12. Nim 2.2.12's JS backend no longer makes a copy forlet b = bon an object parameter, so in the object based layout the swizzle setter's source and destination alias the same JS object andb.wzyx = bclobbers its own input while writing.The fix is in
tools/genswizzle.nim: every setter now reads its components into scalars first and only then assigns, which cannot alias on any backend or layout and no longer relies on copy semantics.src/vmath/swizzle.nimis regenerated, so the diff is large but mechanical (1008 setters).Testing
tests/tests.nimpasses in the default,-d:vmathObjBasedand-d:vmathArrayBasedlayouts:🤖 Generated with Claude Code