Xcode attempts to build simulator arm64 by default, but it can't, causing multiple failures

Number:rdar://FB8809063 Date Originated:Oct 17, 2020 at 4:55 PM
Status:Open Resolved:
Product:Xcode Product Version:12.0.1
Classification: Reproducible:Always
Context: Catalina on an Intel Mac.

The fallout from this can be seen by looking at this Carthage bug: https://github.com/Carthage/Carthage/issues/3019

Workarounds (until Carthage itself is updated) include using a wrapper script to exclude the arm64 architecture from simulator builds. But this only fixes the dependencies. The main project must also be updated to EXCLUDE_ARCHS=arm64 for simulator builds, because by default, Xcode will attempt to build for arm64 when doing a simulator build, even though there's no way to run arm64 Simulator on an Intel Mac. Xcode should be smart enough to know this, and not include arm64 in the default build if it's not explicitly excluded. It wastes time and disk space and ultimately fails.


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