### Bug Description When building a core24 snap for a different architecture, the `BUILD_FOR` variables are set to the host architecture instead of the target. This might be similar to #4702 ### To Reproduce Install snapcraft from `latest/edge` (tested with revision 11178) `snapcraft`, `snapcraft --build-for riscv64`, and `snapcraft --build-for=riscv64` all fail to set the correct architecture. Curiously, `snapcraft --build-for amd64` returns no errors but also doesn't do anything (no-op with no message?) but that may be unrelated. ### Environment Snapcraft on a 23.10 host building with `--use-lxd`. ### snapcraft.yaml ```shell name: my-snap-name # you probably want to 'snapcraft register <name>' base: core24 # the base snap is the execution environment for this snap build-base: devel 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 platforms: riscv64: build-on: [amd64, riscv64] build-for: [riscv64] parts: my-part: # See 'snapcraft plugins' plugin: nil override-build: | echo BUILD_FOR is "${CRAFT_ARCH_BUILD_FOR}" echo BUILD_ON is "${CRAFT_ARCH_BUILD_ON}" echo TRIPLET_BUILD_FOR is "${CRAFT_ARCH_TRIPLET_BUILD_FOR}" echo TRIPLET_BUILD_ON is "${CRAFT_ARCH_TRIPLET_BUILD_ON}" echo PROJECT_NAME is "${CRAFT_PROJECT_NAME}" echo PROJECT_VERSION is "${CRAFT_PROJECT_VERSION}" ``` ### Relevant log output ```shell Starting snapcraft, version 8.0.5.post149+git2fd36174 Logging execution to '/home/dilyn/.local/state/snapcraft/log/snapcraft-20240329-130845.515502.log' Starting snapcraft, version 8.0.5.post149+git2fd36174 Logging execution to '/home/dilyn/.local/state/snapcraft/log/snapcraft-20240329-130845.515502.log' Launching managed ubuntu devel instance... Starting instance Starting snapcraft, version 8.0.5.post149+git2fd36174 Logging execution to '/tmp/snapcraft.log' Starting snapcraft, version 8.0.5.post149+git2fd36174 Logging execution to '/tmp/snapcraft.log' Initialising lifecycle Installing build-packages Installing build-snaps Skipping pull for my-part (already ran) Building my-part :: + echo BUILD_FOR is amd64 :: BUILD_FOR is amd64 :: + echo BUILD_ON is amd64 :: BUILD_ON is amd64 :: + echo TRIPLET_BUILD_FOR is x86_64-linux-gnu :: TRIPLET_BUILD_FOR is x86_64-linux-gnu :: + echo TRIPLET_BUILD_on is x86_64-linux-gnu :: TRIPLET_BUILD_ON is x86_64-linux-gnu :: + echo PROJECT_NAME is my-snap-name :: PROJECT_NAME is my-snap-name :: + echo PROJECT_VERSION is 0.1 :: PROJECT_VERSION is 0.1 Staging my-part Priming my-part Packing... Reading snap metadata... Running linters... Running linter: classic Running linter: library Creating snap package... Packed my-snap-name_0.1_riscv64.snap ``` ### Additional context Also of note: `SNAPCRAFT_PROJECT_{NAME,VERSION}` are invalid variables (though their `CRAFT_` counterparts *are* valid), which means the [documentation](https://snapcraft.io/docs/parts-environment-variables#heading--snapcraft-configuration-core22) is incorrect. `SNAPCRAFT_PROJECT_GRADE` and `CRAFT_PROJECT_GRADE` are never replaced and both raise an unbound variable error, but I think these things are more related to #4702 than this bug.