With the advanced grammar, only the last `- to` clause is respected
Metadata
Current evaluation
Open, triaged Snapcraft bug: multiple advanced-grammar `to` clauses do not behave correctly, causing architecture-inappropriate packages and armhf build failures. Upstream craft-grammar#89 remains open.
Suggested action: keep open
Reason: The report provides a concrete multi-architecture reproducer, Snapcraft 8.6.1 environment, affected YAML, exact librbd-dev failure, and an inversion experiment confirming the ordering-dependent behavior. A maintainer marked the issue triaged, filed upstream craft-grammar#89, and added it to the pulse while noting that scoping is still needed; no resolving fix is identified.
Evaluated by: mr-cal-bot
Impact:
55
Quick Win:
18
Complexity:
62
Confidence:
92
Actionability:
84
Issue body
### Bug Description
In the LXD snap, we have some parts that are meant to be supported on some arches only. For example, we don't want to ship QEMU for `armhf` nor `riscv64`. As such, the `qemu` part is constructed to avoid installing the `build-packages` and the `stage-packages` when building for `armhf`/`riscv64`:
```
qemu:
build-packages:
- to armhf:
- cmake # placeholder pkg (actually used by lxd part) to avoid installing build-packages on unsupported arches
- to riscv64:
- cmake # placeholder pkg (actually used by lxd part) to avoid installing build-packages on unsupported arches
- else:
- bison
- ...
- librbd-dev
stage-packages:
- to armhf:
- acl # placeholder pkg (actually used by lxd part) to avoid installing stage-packages on unsupported arches
- to riscv64:
- acl # placeholder pkg (actually used by lxd part) to avoid installing stage-packages on unsupported arches
- else:
- genisoimage
- ...
- qemu-system-data # This is needed due to --disable-install-blobs.
...
```
However, only the last `- to $ARCH:` clause seems to be respected as on `armhf`, the builds on LP builders always fail complaining that `librbd-dev` is not available. `librbd-dev` is indeed not available for `armhf` which is the whole reason why we try to exclude it with the `- to`/`- else` clauses.
The exclusion works for the `- to riscv64:` as neither `librbd-dev` nor `qemu-system-data` are found in the `riscv64` build logs.
**important**: Inverting the `- to armhf:` and `- to riscv64:` made the `armhf` build work as it then stops trying to pull `librbd-dev`
### To Reproduce
`snapcraft remote-build --platform amd64,armhf,riscv64` on a cloned repo from https://github.com/canonical/lxd-pkg-snap
### Environment
```
$ snap list snapcraft
Name Version Rev Tracking Publisher Notes
snapcraft 8.6.1 13459 latest/stable canonical✓ classic
```
### snapcraft.yaml
```yaml
https://github.com/canonical/lxd-pkg-snap/blob/f3327146996d52e66f8726a88766021f678e2575/snapcraft.yaml
```
### Relevant log output
```shell
Running pull phase...
Initialising lifecycle
Installing build-packages
Cannot find package listed in 'build-packages': librbd-dev
```
### Additional context
_No response_
Evaluation history
| Date | Model | Scores | Action | Summary |
|---|---|---|---|---|
| stealth/space-bunny-alpha |
Impact:
55
Quick Win:
18
Complexity:
62
Confidence:
92
Actionability:
84
|
keep open | Open, triaged Snapcraft bug: multiple advanced-grammar `to` clauses do not behave correctly, causing architecture-inappropriate packages and armhf build failures. Upstream craft-grammar#89 remains open. | |
| qwen/qwen3.6-35b-a3b |
Impact:
65
Quick Win:
27
Complexity:
45
Confidence:
80
Actionability:
75
|
keep open | Multiple `- to $ARCH:` clauses in build-packages/stage-packages only respect the last one, causing wrong packages on multi-arch builds. Upstream bug filed in craft-grammar#89. | |
| qwen/qwen3.8-27b |
Impact:
65
Quick Win:
29
Staleness:
45
Complexity:
55
Confidence:
80
Support Request:
5
|
keep open | Advanced grammar bug: when a list has multiple `- to <arch>` clauses plus `else`, only the last `to` clause is respected, so e.g. armhf still pulls packages meant for other arches. Triaged, tracked upstream at craft-grammar#89, and added to a snapcraft pulse (June 2025) pending scoping; no fix yet. | |
| qwen/qwen3.6-35b-a3b |
Staleness:
65
Complexity:
45
Confidence:
90
Support Request:
5
|
keep open | Bug where multiple `- to <arch>` clauses in build/stage-packages only respect the last one. Triaged, upstream craft-grammar issue created, currently awaiting scoping for next pulse. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
75
Complexity:
50
Confidence:
90
Support Request:
10
|
keep open | Bug in Snapcraft's advanced grammar where multiple - to <arch> clauses in package lists only respect the last one, causing incorrect package resolution on specific architectures. Currently triaged, with an upstream fix tracked and added to a development pulse for scoping. |
Update history
No update history recorded yet.
Related work
-
Blocked By:
canonical/craft-grammar#89
(confidence 95%)
A maintainer explicitly filed this upstream bug for the unexpected behavior of multiple `to` statements; that issue remains open.
Related issues
| Issue | Project | State | Summary | Similarity |
|---|---|---|---|---|
| #6064 Extend advanced grammer to all keys of snapcraft | snapcraft | open | Advanced grammar remains limited to selected keys, limiting clean architecture-specific apps, part omission, and plugin parameters. The feature is untriaged; plugin-parameter support is tracked in craft-application #985. |