perf: stop allocating a warnings array for a clean compile - #49
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Every document allocated a string array even when the compiler reported no warnings, which is the common case. Array.Empty covers it without allocating. Array.AsReadOnly already returns the shared empty collection for a zero-length array, so the wrapper it is passed to costs nothing either way.
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Every
TypstDocumentallocatednew string[warningCount]even when the compiler reported no warnings, which is the common case.Array.Empty<string>()covers it without allocating.Scope, stated plainly: this saves 24 bytes per warning-free compile, and nothing else.
Array.AsReadOnlyhas returned the shared empty collection for a zero-length array since .NET 8, so the wrapper it is passed to was already free. Against a compile that takes milliseconds and allocates megabytes of native memory, this is below noise — it is here because it is one line and free, not because it is measurable.The test covers the warning-free case, which had none. It pins the public contract rather than the allocation, so it passes on
developtoo; it is coverage, not a regression guard.57/57 pass, clean on net8/9/10.