Build fails: error: emit-module command failed with exit code 1

[steinmb]

Hi
Trying to build, follow BUILDING.md but it fails error: emit-module command failed with exit code 1 (use -v to see invocation). Am I missing something?

• MacOS 26.0.1
• Xcode Version 26.0.1 (17A400)
• Build from: ~/macos_containers/container
• GNU Make 3.81

❯ git clone https://github.com/apple/container.git
Cloning into 'container'...
remote: Enumerating objects: 2745, done.
remote: Counting objects: 100% (788/788), done.
remote: Compressing objects: 100% (234/234), done.
remote: Total 2745 (delta 685), reused 554 (delta 554), pack-reused 1957 (from 2)
Receiving objects: 100% (2745/2745), 1.75 MiB | 4.33 MiB/s, done.
Resolving deltas: 100% (1780/1780), done.

❯ cd container
❯ make all test integration

Building container binaries...
swift-driver version: 1.127.14.1 Apple Swift version 6.2 (swiftlang-6.2.0.19.9 clang-1700.3.19.1)
Target: arm64-apple-macosx26.0
Fetching https://github.com/swiftlang/swift-docc-symbolkit
Fetching https://github.com/apple/swift-nio-extras.git
Fetching https://github.com/apple/swift-crypto.git
Fetching https://github.com/apple/swift-http-types.git
Fetching https://github.com/Bouke/DNS.git
Fetching https://github.com/apple/swift-log.git
Fetching https://github.com/apple/swift-async-algorithms.git
Fetching https://github.com/apple/swift-atomics.git
Fetching https://github.com/grpc/grpc-swift.git
Fetched https://github.com/apple/swift-atomics.git from cache (0.84s)
Fetching https://github.com/apple/swift-nio.git
Fetched https://github.com/apple/swift-nio-extras.git from cache (1.27s)
Fetched https://github.com/apple/swift-log.git from cache (1.27s)
Fetched https://github.com/swiftlang/swift-docc-symbolkit from cache (1.27s)
Fetching https://github.com/apple/swift-collections.git
Fetching https://github.com/apple/swift-system.git
Fetching https://github.com/apple/swift-nio-transport-services.git
Fetched https://github.com/Bouke/DNS.git from cache (7.27s)
Fetched https://github.com/grpc/grpc-swift.git from cache (7.27s)
Fetched https://github.com/apple/swift-http-types.git from cache (7.27s)
Fetched https://github.com/apple/swift-async-algorithms.git from cache (7.27s)
Fetched https://github.com/apple/swift-crypto.git from cache (7.27s)
Fetching https://github.com/orlandos-nl/DNSClient.git
Fetching https://github.com/apple/swift-asn1.git
Fetching https://github.com/apple/containerization.git
Fetching https://github.com/apple/swift-nio-ssl.git
Fetching https://github.com/swift-server/async-http-client.git
Fetched https://github.com/orlandos-nl/DNSClient.git from cache (0.72s)
Fetching https://github.com/swift-server/swift-service-lifecycle.git
Fetched https://github.com/apple/swift-system.git from cache (6.83s)
Fetched https://github.com/apple/swift-collections.git from cache (6.83s)
Fetched https://github.com/apple/swift-nio-transport-services.git from cache (6.83s)
Fetching https://github.com/apple/swift-algorithms.git
Fetching https://github.com/apple/swift-protobuf.git
Fetching https://github.com/apple/swift-argument-parser.git
Fetched https://github.com/swift-server/swift-service-lifecycle.git from cache (0.84s)
Fetching https://github.com/apple/swift-http-structured-headers.git
Fetched https://github.com/apple/containerization.git from cache (2.01s)
Fetched https://github.com/swift-server/async-http-client.git from cache (2.01s)
Fetched https://github.com/apple/swift-asn1.git from cache (2.01s)
Fetching https://github.com/apple/swift-certificates.git
Fetching https://github.com/swiftlang/swift-docc-plugin.git
Fetching https://github.com/apple/swift-nio-http2.git
Fetched https://github.com/apple/swift-http-structured-headers.git from cache (1.41s)
Fetching https://github.com/apple/swift-numerics.git
Fetched https://github.com/apple/swift-numerics.git from cache (0.91s)
Fetched https://github.com/apple/swift-certificates.git from cache (2.63s)
Fetched https://github.com/apple/swift-nio-http2.git from cache (2.63s)
Fetched https://github.com/swiftlang/swift-docc-plugin.git from cache (2.63s)
Fetched https://github.com/apple/swift-nio-ssl.git from cache (4.72s)
Fetched https://github.com/apple/swift-nio.git from cache (17.16s)
Fetched https://github.com/apple/swift-protobuf.git from cache (11.20s)
Fetched https://github.com/apple/swift-algorithms.git from cache (11.20s)
Fetched https://github.com/apple/swift-argument-parser.git from cache (11.20s)
Creating working copy for https://github.com/apple/swift-nio-extras.git
Creating working copy for https://github.com/Bouke/DNS.git
Creating working copy for https://github.com/apple/swift-http-types.git
Creating working copy for https://github.com/apple/swift-crypto.git
Creating working copy for https://github.com/grpc/grpc-swift.git
Creating working copy for https://github.com/apple/swift-nio.git
Creating working copy for https://github.com/apple/swift-atomics.git
Creating working copy for https://github.com/apple/swift-log.git
Creating working copy for https://github.com/apple/swift-nio-ssl.git
Creating working copy for https://github.com/apple/swift-nio-transport-services.git
Working copy of https://github.com/apple/swift-nio-transport-services.git resolved at 1.25.1
Working copy of https://github.com/apple/swift-http-types.git resolved at 1.4.0
Working copy of https://github.com/apple/swift-log.git resolved at 1.6.4
Creating working copy for https://github.com/apple/swift-collections.git
Creating working copy for https://github.com/apple/swift-system.git
Creating working copy for https://github.com/orlandos-nl/DNSClient.git
Creating working copy for https://github.com/apple/swift-protobuf.git
Working copy of https://github.com/apple/swift-nio-extras.git resolved at 1.29.0
Creating working copy for https://github.com/swift-server/swift-service-lifecycle.git
Creating working copy for https://github.com/apple/swift-algorithms.git
Working copy of https://github.com/orlandos-nl/DNSClient.git resolved at 2.4.4
Creating working copy for https://github.com/apple/containerization.git
Working copy of https://github.com/apple/swift-system.git resolved at 1.6.2
Creating working copy for https://github.com/swift-server/async-http-client.git
Working copy of https://github.com/Bouke/DNS.git resolved at 1.2.0
Working copy of https://github.com/apple/swift-algorithms.git resolved at 1.2.1
Creating working copy for https://github.com/apple/swift-http-structured-headers.git
Working copy of https://github.com/apple/swift-atomics.git resolved at 1.3.0
Working copy of https://github.com/swift-server/async-http-client.git resolved at 1.26.1
Creating working copy for https://github.com/apple/swift-argument-parser.git
Creating working copy for https://github.com/apple/swift-certificates.git
Creating working copy for https://github.com/apple/swift-nio-http2.git
Working copy of https://github.com/apple/containerization.git resolved at 0.8.1
Creating working copy for https://github.com/swiftlang/swift-docc-plugin.git
Creating working copy for https://github.com/apple/swift-async-algorithms.git
Working copy of https://github.com/swift-server/swift-service-lifecycle.git resolved at 2.8.0
Creating working copy for https://github.com/apple/swift-asn1.git
Creating working copy for https://github.com/apple/swift-numerics.git
Working copy of https://github.com/apple/swift-http-structured-headers.git resolved at 1.4.0
Creating working copy for https://github.com/swiftlang/swift-docc-symbolkit
Working copy of https://github.com/apple/swift-nio-ssl.git resolved at 2.33.0
Working copy of https://github.com/apple/swift-collections.git resolved at 1.2.1
Working copy of https://github.com/apple/swift-nio.git resolved at 2.86.0
Working copy of https://github.com/grpc/grpc-swift.git resolved at 1.26.1
Working copy of https://github.com/apple/swift-protobuf.git resolved at 1.30.0
Working copy of https://github.com/apple/swift-argument-parser.git resolved at 1.6.1
Working copy of https://github.com/apple/swift-crypto.git resolved at 3.14.0
Working copy of https://github.com/apple/swift-certificates.git resolved at 1.12.0
Working copy of https://github.com/apple/swift-numerics.git resolved at 1.0.3
Working copy of https://github.com/apple/swift-async-algorithms.git resolved at 1.0.4
Working copy of https://github.com/swiftlang/swift-docc-plugin.git resolved at 1.4.5
Working copy of https://github.com/apple/swift-asn1.git resolved at 1.4.0
Working copy of https://github.com/swiftlang/swift-docc-symbolkit resolved at 1.0.0
Working copy of https://github.com/apple/swift-nio-http2.git resolved at 1.38.0
Building for debugging...
[2161/2161] Applying container
Build complete! (105.26s)
Installing container binaries from /Users/steinmb/macos_containers/container/.build/arm64-apple-macosx/debug into bin/debug/staging/...
Install uninstaller script
Signing container binaries...
bin/debug/staging/bin/container: replacing existing signature
bin/debug/staging/bin/container-apiserver: replacing existing signature
bin/debug/staging/libexec/container/plugins/container-core-images/bin/container-core-images: replacing existing signature
bin/debug/staging/libexec/container/plugins/container-runtime-linux/bin/container-runtime-linux: replacing existing signature
bin/debug/staging/libexec/container/plugins/container-network-vmnet/bin/container-network-vmnet: replacing existing signature
Creating application installer
pkgbuild: Inferring bundle components from contents of bin/debug/staging/
pkgbuild: Wrote package to bin/debug/container-installer-unsigned.pkg
Installing container installer package
[1/1] Planning build
Building for debugging...
/Users/steinmb/macos_containers/container/Tests/ContainerPluginTests/CommandLine+ExecutableTest.swift:18:8: error: no such module 'Testing'
16 |
17 | import Foundation
18 | import Testing
   |        `- error: no such module 'Testing'
19 |
20 | @testable import ContainerPlugin
error: emit-module command failed with exit code 1 (use -v to see invocation)
/Users/steinmb/macos_containers/container/Tests/DNSServerTests/CompositeResolverTest.swift:20:8: error: no such module 'Testing'
18 |
19 | import DNS
20 | import Testing
   |        `- error: no such module 'Testing'
21 |
22 | @testable import DNSServer
error: emit-module command failed with exit code 1 (use -v to see invocation)
/Users/steinmb/macos_containers/container/Tests/SocketForwarderTests/LRUCacheTest.swift:17:8: error: no such module 'Testing'
15 | //===----------------------------------------------------------------------===//
16 |
17 | import Testing
   |        `- error: no such module 'Testing'
18 |
19 | @testable import SocketForwarder
/Users/steinmb/macos_containers/container/Tests/SocketForwarderTests/LRUCacheTest.swift:17:8: error: no such module 'Testing'
15 | //===----------------------------------------------------------------------===//
16 |
17 | import Testing
   |        `- error: no such module 'Testing'
18 |
19 | @testable import SocketForwarder
/Users/steinmb/macos_containers/container/Tests/SocketForwarderTests/LRUCacheTest.swift:17:8: error: no such module 'Testing'
15 | //===----------------------------------------------------------------------===//
16 |
17 | import Testing
   |        `- error: no such module 'Testing'
18 |
19 | @testable import SocketForwarder
/Users/steinmb/macos_containers/container/Tests/DNSServerTests/CompositeResolverTest.swift:20:8: error: no such module 'Testing'
18 |
19 | import DNS
20 | import Testing
   |        `- error: no such module 'Testing'
21 |
22 | @testable import DNSServer
error: emit-module command failed with exit code 1 (use -v to see invocation)
/Users/steinmb/macos_containers/container/Tests/SocketForwarderTests/LRUCacheTest.swift:17:8: error: no such module 'Testing'
15 | //===----------------------------------------------------------------------===//
16 |
17 | import Testing
   |        `- error: no such module 'Testing'
18 |
19 | @testable import SocketForwarder
/Users/steinmb/macos_containers/container/Tests/ContainerPluginTests/CommandLine+ExecutableTest.swift:18:8: error: no such module 'Testing'
16 |
17 | import Foundation
18 | import Testing
   |        `- error: no such module 'Testing'
19 |
20 | @testable import ContainerPlugin
/Users/steinmb/macos_containers/container/Tests/DNSServerTests/CompositeResolverTest.swift:20:8: error: no such module 'Testing'
18 |
19 | import DNS
20 | import Testing
   |        `- error: no such module 'Testing'
21 |
22 | @testable import DNSServer
/Users/steinmb/macos_containers/container/Tests/ContainerPluginTests/CommandLine+ExecutableTest.swift:18:8: error: no such module 'Testing'
16 |
17 | import Foundation
18 | import Testing
   |        `- error: no such module 'Testing'
19 |
20 | @testable import ContainerPlugin
/Users/steinmb/macos_containers/container/Tests/SocketForwarderTests/LRUCacheTest.swift:17:8: error: no such module 'Testing'
15 | //===----------------------------------------------------------------------===//
16 |
17 | import Testing
   |        `- error: no such module 'Testing'
18 |
19 | @testable import SocketForwarder
/Users/steinmb/macos_containers/container/Tests/DNSServerTests/CompositeResolverTest.swift:20:8: error: no such module 'Testing'
18 |
19 | import DNS
20 | import Testing
   |        `- error: no such module 'Testing'
21 |
22 | @testable import DNSServer
error: emit-module command failed with exit code 1 (use -v to see invocation)
/Users/steinmb/macos_containers/container/Tests/TerminalProgressTests/ProgressBarTests.swift:19:8: error: no such module 'XCTest'
 17 | //
 18 |
 19 | import XCTest
    |        `- error: no such module 'XCTest'
 20 |
 21 | @testable import TerminalProgress
/Users/steinmb/macos_containers/container/Tests/SocketForwarderTests/LRUCacheTest.swift:17:8: error: no such module 'Testing'
15 | //===----------------------------------------------------------------------===//
16 |
17 | import Testing
   |        `- error: no such module 'Testing'
18 |
19 | @testable import SocketForwarder
/Users/steinmb/macos_containers/container/Tests/DNSServerTests/CompositeResolverTest.swift:20:8: error: no such module 'Testing'
18 |
19 | import DNS
20 | import Testing
   |        `- error: no such module 'Testing'
21 |
22 | @testable import DNSServer
/Users/steinmb/macos_containers/container/Tests/ContainerPluginTests/CommandLine+ExecutableTest.swift:18:8: error: no such module 'Testing'
16 |
17 | import Foundation
18 | import Testing
   |        `- error: no such module 'Testing'
19 |
20 | @testable import ContainerPlugin
/Users/steinmb/macos_containers/container/Tests/ContainerPluginTests/CommandLine+ExecutableTest.swift:18:8: error: no such module 'Testing'
16 |
17 | import Foundation
18 | import Testing
   |        `- error: no such module 'Testing'
19 |
20 | @testable import ContainerPlugin
/Users/steinmb/macos_containers/container/Tests/DNSServerTests/CompositeResolverTest.swift:20:8: error: no such module 'Testing'
18 |
19 | import DNS
20 | import Testing
   |        `- error: no such module 'Testing'
21 |
22 | @testable import DNSServer
/Users/steinmb/macos_containers/container/Tests/TerminalProgressTests/ProgressBarTests.swift:19:8: error: no such module 'XCTest'
 17 | //
 18 |
 19 | import XCTest
    |        `- error: no such module 'XCTest'
 20 |
 21 | @testable import TerminalProgress
[35/72] Compiling DNSServerTests NxDomainResolverTest.swift
error: fatalError
make: *** [test] Error 1

[jglogan]

What do you get for:

which swift
env | grep SWIFT
swift sdk list
swiftly list
/usr/bin/swift --version
xcode-select -p

[steinmb]

Thank you for your swift reply (pun intended):

❯ which swift
env | grep SWIFT
swift sdk list
swiftly list
/usr/bin/swift --version
xcode-select -p
/usr/bin/swift

No Swift SDKs are currently installed.
zsh: command not found: swiftly
swift-driver version: 1.127.14.1 Apple Swift version 6.2 (swiftlang-6.2.0.19.9 clang-1700.3.19.1)
Target: arm64-apple-macosx26.0
/Library/Developer/CommandLineTools

Clean machine face palm. Follow https://www.swift.org/install/macos/ installation. And rerun:

❯ which swift
env | grep SWIFT
swift sdk list
swiftly list
/usr/bin/swift --version
xcode-select -p

/Users/myuser/.swiftly/bin/swift
SWIFTLY_HOME_DIR=/Users/myuser/.swiftly
SWIFTLY_BIN_DIR=/Users/myuser/.swiftly/bin
SWIFTLY_TOOLCHAINS_DIR=/Users/myuser/Library/Developer/Toolchains
No Swift SDKs are currently installed.
Installed release toolchains
----------------------------
Swift 6.2.0 (in use) (default)

Installed snapshot toolchains
-----------------------------
swift-driver version: 1.127.14.1 Apple Swift version 6.2 (swiftlang-6.2.0.19.9 clang-1700.3.19.1)
Target: arm64-apple-macosx26.0
/Library/Developer/CommandLineTools

Build still fails. Do I also need the Swift SDK installed?

make all test integration

Building container binaries...
swift-driver version: 1.127.14.1 Apple Swift version 6.2 (swiftlang-6.2.0.19.9 clang-1700.3.19.1)
Target: arm64-apple-macosx26.0
[1/1] Planning build
Building for debugging...
[7/7] Write swift-version--1AB21518FC5DEDBE.txt
Build complete! (13.25s)
Installing container binaries from /Users/steinmb/macos_containers/container/.build/arm64-apple-macosx/debug into bin/debug/staging/...
Install uninstaller script
Signing container binaries...
bin/debug/staging/bin/container: replacing existing signature
bin/debug/staging/bin/container-apiserver: replacing existing signature
bin/debug/staging/libexec/container/plugins/container-core-images/bin/container-core-images: replacing existing signature
bin/debug/staging/libexec/container/plugins/container-runtime-linux/bin/container-runtime-linux: replacing existing signature
bin/debug/staging/libexec/container/plugins/container-network-vmnet/bin/container-network-vmnet: replacing existing signature
Creating application installer
pkgbuild: Inferring bundle components from contents of bin/debug/staging/
pkgbuild: Wrote package to bin/debug/container-installer-unsigned.pkg
Installing container installer package
[1/1] Planning build
Building for debugging...
/Users/steinmb/macos_containers/container/Tests/SocketForwarderTests/LRUCacheTest.swift:17:8: error: no such module 'Testing'
15 | //===----------------------------------------------------------------------===//
16 |
17 | import Testing
   |        `- error: no such module 'Testing'
18 |
19 | @testable import SocketForwarder
/Users/steinmb/macos_containers/container/Tests/DNSServerTests/CompositeResolverTest.swift:20:8: error: no such module 'Testing'
18 |
19 | import DNS
20 | import Testing
   |        `- error: no such module 'Testing'
21 |
22 | @testable import DNSServer
/Users/steinmb/macos_containers/container/Tests/DNSServerTests/CompositeResolverTest.swift:20:8: error: no such module 'Testing'
18 |
19 | import DNS
20 | import Testing
   |        `- error: no such module 'Testing'
21 |
22 | @testable import DNSServer
/Users/steinmb/macos_containers/container/Tests/TerminalProgressTests/ProgressBarTests.swift:19:8: error: no such module 'XCTest'
 17 | //
 18 |
 19 | import XCTest
    |        `- error: no such module 'XCTest'
 20 |
 21 | @testable import TerminalProgress
/Users/steinmb/macos_containers/container/Tests/SocketForwarderTests/LRUCacheTest.swift:17:8: error: no such module 'Testing'
15 | //===----------------------------------------------------------------------===//
16 |
17 | import Testing
   |        `- error: no such module 'Testing'
18 |
19 | @testable import SocketForwarder
/Users/steinmb/macos_containers/container/Tests/DNSServerTests/CompositeResolverTest.swift:20:8: error: no such module 'Testing'
18 |
19 | import DNS
20 | import Testing
   |        `- error: no such module 'Testing'
21 |
22 | @testable import DNSServer
error: emit-module command failed with exit code 1 (use -v to see invocation)
/Users/steinmb/macos_containers/container/Tests/TerminalProgressTests/ProgressBarTests.swift:19:8: error: no such module 'XCTest'
 17 | //
 18 |
 19 | import XCTest
    |        `- error: no such module 'XCTest'
 20 |
 21 | @testable import TerminalProgress
error: emit-module command failed with exit code 1 (use -v to see invocation)
/Users/steinmb/macos_containers/container/Tests/DNSServerTests/CompositeResolverTest.swift:20:8: error: no such module 'Testing'
18 |
19 | import DNS
20 | import Testing
   |        `- error: no such module 'Testing'
21 |
22 | @testable import DNSServer
[15/62] Emitting module DNSServerTests
error: fatalError
make: *** [test] Error 1

container on  main [?] via 🐦 v6.2 took 24s

[rgov]

How did you resolve the issue? Or did you close it with no resolution?

[izzyleung]

#700 (comment) in case y'all still need this help

[izzyleung]

Hi there, ran into the same issue. The solution is simple:

sudo xcode-select -s /Applications/Xcode.app

tl;dr: if you use the Developer Tools installed via xcode-select --install, swift-testing/XCTest won't be available.
Solution is to switch to the full Developer Tools that comes with XCode that has all the testing libraries and support.

[izzyleung]

Oh, also forgot to mention. rm -rf .build && make clean to ensure a clean build, or you might see - error: missing required module '_TestingInternals'

[steinmb]

Thank you, I'll dust of the repo. and try again.