jayayres (JIRA User) I can't seem to reproduce this with 13.2 (not command-line-tools).

Have you tried it with a full Xcode or with an OSS Toolchain (https://www.swift.org/download/)?

Here's a way to reproduce it:

1. Get a 16" MacBook Pro M1 Max.

2. Install macOS 12.1 (21C52).

3. Install Xcode 13.2.1.xip.

4. Use xcode-select to select Xcode 13.2.1.

5. git clone https://github.com/apple/swift-protobuf.git

6. cd swift-protobuf

7. xcrun swift build -c release --product protoc-gen-swift --arch arm64 --arch x86_64

8. echo $?

For me, the exit status ($?) is 1, indicating failure. Note, though, that the last line of output is

100%: Build succeeded 

and indeed ./.build/apple/Products/Release/protoc-gen-swift is an apparently complete, working executable.

In my testing, I have to build for both architectures simultaneously to produce the failure. Building for just one architecture at a time does not induce failure.

Comment by Jay Ayres (JIRA)

I can't reproduce this from within Xcode itself. I am confirming as well, for the PackageBug.zip example, that this fails from the command line with error code 1 when I do:

swift build -c release --arch arm64 --arch x86_64

but single-architecture builds do not fail.