### Bug Description The new `remote-build` method will fail under particular configurations of the `architectures` section in a `snapcraft.yaml`. ### To Reproduce ``` dilyn@Ares:~/cross-test -> mkdir cross-test && cd cross-test dilyn@Ares:~/cross-test -> snapcraft init {add the below section to the snapcraft.yaml} architectures: - build-on: [amd64] build-for: [arm64] dilyn@Ares:~/cross-test -> snapcraft dilyn@Ares:~/cross-test -> snapcraft remote-build dilyn@Ares:~/cross-test -> snapcraft remote-build --build-for=arm64 ``` ### Environment Ubuntu 23.04 snapcraft 8.x (rev. 10143) ### snapcraft.yaml ```shell name: my-snap-name # you probably want to 'snapcraft register <name>' base: core22 # the base snap is the execution environment for this snap version: '0.1' # just for humans, typically '1.2+git' or '1.3.2' summary: Single-line elevator pitch for your amazing snap # 79 char long summary description: | This is my-snap's description. You have a paragraph or two to tell the most important story about your snap. Keep it under 100 words though, we live in tweetspace and your description wants to look good in the snap store. grade: devel # must be 'stable' to release into candidate/stable channels confinement: devmode # use 'strict' once you have the right plugs and slots architectures: - build-on: [amd64] build-for: [arm64] parts: my-part: # See 'snapcraft plugins' plugin: nil ``` ### Relevant log output Logs from three different attempts: ```shell dilyn@Ares:~/cross-test -> snapcraft Starting Snapcraft 8.0.0 Logging execution to '/home/dilyn/.local/state/snapcraft/log/snapcraft-20231212-201938.403999.log' Running on amd64 for arm64 Launching instance... Starting Snapcraft 8.0.0 Logging execution to '/tmp/snapcraft.log' Running on amd64 for arm64 Initializing parts lifecycle Installing build-packages Installing build-snaps Pulling my-part Building my-part Staging my-part Priming my-part Extracting and updating metadata... Copying snap assets... Generating snap metadata... Generated snap metadata Generating snap manifest... Generated snap manifest Reading snap metadata... Running linters... Running linter: classic Running linter: library Creating snap package... Created snap package my-snap-name_0.1_arm64.snap dilyn@Ares:~/cross-test -> snapcraft remote-build Starting Snapcraft 8.0.0 Logging execution to '/home/dilyn/.local/state/snapcraft/log/snapcraft-20231212-202007.454275.log' snapcraft remote-build is experimental and is subject to change - use with caution. All data sent to remote builders will be publicly available. Are you sure you want to continue? [y/N]: y Issues while validating snapcraft.yaml: The 'architectures[0]' property does not match the required schema: additional properties are not allowed ('build-for' was unexpected) or orderedDict([('build-on', ['amd64']), ('build-for', ['arm64'])]) is not of type 'string' dilyn@Ares:~/cross-test -> snapcraft remote-build --build-for=arm64 Starting Snapcraft 8.0.0 Logging execution to '/home/dilyn/.local/state/snapcraft/log/snapcraft-20231212-202017.786399.log' snapcraft remote-build is experimental and is subject to change - use with caution. All data sent to remote builders will be publicly available. Are you sure you want to continue? [y/N]: y Issues while validating snapcraft.yaml: The 'architectures[0]' property does not match the required schema: additional properties are not allowed ('build-for' was unexpected) or orderedDict([('build-on', ['amd64']), ('build-for', ['arm64'])]) is not of type 'string' ``` ### Additional context Some additional behavior happens in case I expand the `architectures` section to include an additional architecture: ``` architectures: - build-on: [amd64, arm64] build-for: [arm64] - build-on: [amd64, armhf] build-for: [armhf] ``` Output: ``` dilyn@Ares:~/cross-test -> snapcraft remote-build Starting Snapcraft 8.0.0 Logging execution to '/home/dilyn/.local/state/snapcraft/log/snapcraft-20231212-202200.825177.log' snapcraft remote-build is experimental and is subject to change - use with caution. All data sent to remote builders will be publicly available. Are you sure you want to continue? [y/N]: y Issues while validating snapcraft.yaml: The 'architectures' property does not match the required schema: multiple items will build snaps that claim to run on 'amd64' dilyn@Ares:~/cross-test -> snapcraft remote-build --build-for=arm64 Starting Snapcraft 8.0.0 Logging execution to '/home/dilyn/.local/state/snapcraft/log/snapcraft-20231212-202300.295288.log' snapcraft remote-build is experimental and is subject to change - use with caution. All data sent to remote builders will be publicly available. Are you sure you want to continue? [y/N]: y Issues while validating snapcraft.yaml: The 'architectures' property does not match the required schema: multiple items will build snaps that claim to run on 'amd64' ``` Some extra odd behavior happens if I disable fallback with `SNAPCRAFT_REMOTE_BUILD_STRATEGY=disable-fallback` and expand the architectures stanza as above: ``` dilyn@Ares:~/cross-test -> SNAPCRAFT_REMOTE_BUILD_STRATEGY=disable-fallback snapcraft remote-build Starting Snapcraft 8.0.0 Logging execution to '/home/dilyn/.local/state/snapcraft/log/snapcraft-20231212-202415.233506.log' snapcraft remote-build is experimental and is subject to change - use with caution. All data sent to remote builders will be publicly available. Are you sure you want to continue? [y/N]: y Setting up launchpad environment Looking for existing build No existing build found If interrupted, resume with: 'snapcraft remote-build --recover --build-id snapcraft-my-snap-name-78a0da0edb2a2b9b359107180b3914fe' Starting build creating git repo: name=snapcraft-my-snap-name-78a0da0edb2a2b9b359107180b3914fe, owner=/~dilyn-corner, target=/~dilyn-corner Sending build data to Launchpad: https://dilyn-corner:<token>@git.launchpad.net/~dilyn-corner/+git/snapcraft-my-snap-name-78a0da0edb2a2b9b359107180b3914fe/ Registering snap job on Launchpad... Issuing build request on Launchpad... Waiting on Launchpad build request... Build request accepted: 84571241 Building Building snap package for amd64, amd64, arm64, and armhf. This may take some time to finish. Building... amd64: Needs building, amd64: Needs building amd64: Currently building, amd64: Currently building - (8.0s) amd64: Currently building, amd64: Currently building - (19.amd64: Currently building, amd64: Currently building amd64: Currently building, amd64: Currently building amd64: Currently building, amd64: Currently building amd64: Currently building, amd64: Currently building amd64: Currently building, amd64: Currently building amd64: Currently building, amd64: Currently building amd64: Currently building, amd64: Currently building amd64: Currently building, amd64: Currently building amd64: Currently building, amd64: Currently building amd64: Currently building, amd64: Currently building amd64: Currently building, amd64: Currently building amd64: Gathering build output, amd64: Gathering build output amd64: Uploading build, amd64: Uploading build amd64: Successfully built, amd64: Successfully built Downloading artifacts... Downloading: https://launchpad.net/~dilyn-corner/+snap/snapcraft-my-snap-name-78a0da0edb2a2b9b359107180b3914fe/+build/2326477/+files/my-snap-name_0.1_arm64.snap Snapped my-snap-name_0.1_arm64.snap Downloading: https://launchpad.net/~dilyn-corner/+snap/snapcraft-my-snap-name-78a0da0edb2a2b9b359107180b3914fe/+build/2326477/+files/buildlog_snap_ubuntu_jammy_amd64_snapcraft-my-snap-name-78a0da0edb2a2b9b359107180b3914fe_BUILDING.txt.gz Build log available at 'my-snap-name_amd64.txt'. Downloading: https://launchpad.net/~dilyn-corner/+snap/snapcraft-my-snap-name-78a0da0edb2a2b9b359107180b3914fe/+build/2326478/+files/my-snap-name_0.1_arm64.snap Snapped my-snap-name_0.1_arm64.snap Downloading: https://launchpad.net/~dilyn-corner/+snap/snapcraft-my-snap-name-78a0da0edb2a2b9b359107180b3914fe/+build/2326478/+files/my-snap-name_0.1_armhf.snap Snapped my-snap-name_0.1_armhf.snap Downloading: https://launchpad.net/~dilyn-corner/+snap/snapcraft-my-snap-name-78a0da0edb2a2b9b359107180b3914fe/+build/2326478/+files/buildlog_snap_ubuntu_jammy_amd64_snapcraft-my-snap-name-78a0da0edb2a2b9b359107180b3914fe_BUILDING.txt.gz Build log available at 'my-snap-name_amd64.1.txt'. Build complete. Cleaning Cleaning existing builds and artefacts. Removing snap job from Launchpad... Deleting source repository from Launchpad... Build completed dilyn@Ares:~/cross-test -> ls my-snap-name_0.1_arm64.snap my-snap-name_0.1_armhf.snap my-snap-name_amd64.1.txt my-snap-name_amd64.txt snap ``` Note the repetition of building for `amd64`; especially odd as I don't expect a snap to be built for AMD64 *at all* given my `architectures` listed. The two AMD64 build logs indicate that the builds happened on AMD64 machines, with the first log reporting that one snap was successfully built (an ARM64 one), and the second log indicating that two snaps were successfully built (both ARM64 and ARMHF). Both the snap files seem to have all the correct information for being installed on their respective architectures. However, if I had built a non-trivial snap, I'm not convinced they would actually function properly (e.g. AMD64 libs might be inside them). Setting `force-fallback` instead results in the same error message as I mentioned earlier in this section (as expected).