Multiple `charmcraft pack` fail on mismatching platforms
Metadata
Current evaluation
Charmcraft 4.2.0+ reuses a managed LXD instance from a prior `charmcraft pack` of a different project, causing the second pack to fail with 'Platform not found in the project definition' when platform sets differ. Still reproducible on 4.3.1 per reporter's 2026-08-17 comment; no maintainer response or labels yet.
Suggested action: needs triage
Reason: The issue has no labels, no assignee, and no maintainer comments — only the reporter's own follow-up (2026-08-17) confirming it persists on 4.3.1. It's a clear regression (worked in 4.0.1, broke in 4.2.0) with a concrete reproducer (two consecutive `charmcraft pack` calls with different platform sets), so it needs maintainer triage rather than closure. Complexity is moderate because the root cause likely lies in craft-providers' instance/base-instance reuse logic (the 'Creating instance from base instance' step) rather than charmcraft's own code, which I could not locate in this repo's source.
Impact:
65
Quick Win:
26.0
Staleness:
15
Complexity:
60
Confidence:
70
Support Request:
5
Issue body
### Check existing issues
- [x] I've verified that this bug isn't described by any existing issues.
### Bug description
With Charmcraft 4.0.1, the [charm-lxd](https://github.com/canonical/charm-lxd) CI was building the primary LXD charm for 24.04 and 22.04 followed by an ancillary charm for 24.04 only one:
```
charmcraft pack -v
echo "==> ancillary charm for testing purposes"
charmcraft pack -v --project-dir examples/https-client
```
Now with Charmcraft 4.2.0, packing the ancillary charm fails with:
```
Staging charm
Priming charm
Packing...
Packing charm https-client_ubuntu-24.04-amd64.charm
Packed https-client_ubuntu-24.04-amd64.charm
Launching managed ubuntu 22.04 instance...
Creating instance from base instance
Starting instance
Starting charmcraft, version 4.2.0
Logging execution to '/tmp/charmcraft.log'
Platform 'ubuntu-22.04-amd64' not found in the project definition.
Detailed information: Valid platforms are: 'ubuntu-24.04-amd64', 'ubuntu-24.04-arm64', 'ubuntu-24.04-armhf', 'ubuntu-24.04-ppc64el', 'ubuntu-24.04-riscv64', 'ubuntu-24.04-s390x'.
Failed to run charmcraft in instance
```
The full logs: https://github.com/canonical/charm-lxd/actions/runs/23904129367/job/69708427467
The [main `charmcraft.yaml`](https://github.com/canonical/charm-lxd/blob/b7b57f9660d77c242afc348a26b49b7bed6dcc0e/charmcraft.yaml) and the [anciliary `charmcraft.yaml`](https://github.com/canonical/charm-lxd/blob/b7b57f9660d77c242afc348a26b49b7bed6dcc0e/examples/https-client/charmcraft.yaml)
### Steps to reproduce
Build 2 charms consecutively. The first with:
```
type: charm
platforms:
ubuntu-24.04-amd64:
build-on: [ubuntu@24.04:amd64]
build-for: [ubuntu@24.04:amd64]
ubuntu-22.04-arm64:
build-on: [ubuntu@22.04:amd64]
build-for: [ubuntu@22.04:amd64]
```
And the second with:
```
type: charm
platforms:
ubuntu-24.04-amd64:
build-on: [ubuntu@24.04:amd64]
build-for: [ubuntu@24.04:amd64]
```
Evaluation history
| Date | Model | Scores | Action | Summary |
|---|---|---|---|---|
| qwen/qwen3.8-27b |
Impact:
65
Quick Win:
26.0
Staleness:
15
Complexity:
60
Confidence:
70
Support Request:
5
|
needs triage | Charmcraft 4.2.0+ reuses a managed LXD instance from a prior `charmcraft pack` of a different project, causing the second pack to fail with 'Platform not found in the project definition' when platform sets differ. Still reproducible on 4.3.1 per reporter's 2026-08-17 comment; no maintainer response or labels yet. | |
| qwen/qwen3.6-35b-a3b |
Staleness:
25
Complexity:
45
Confidence:
90
Support Request:
10
|
needs triage | Regression in Charmcraft 4.2.0+ where packing an ancillary charm fails with a platform mismatch error when run after a primary charm with different platforms. Currently unlabelled and awaiting maintainer review. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
70
Complexity:
40
Confidence:
85
Support Request:
10
|
needs triage | Regression in Charmcraft 4.2.0 where packing a secondary charm fails with a platform mismatch error when run after a primary charm. Untriaged, no maintainer response after 110 days. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
75
Complexity:
50
Confidence:
90
Support Request:
10
|
needs triage | Regression in Charmcraft 4.2.0 where consecutive charmcraft pack commands fail due to platform state leakage. Ancillary charm incorrectly expects a platform from the previously built charm. Untriaged, no maintainer response. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
55
Complexity:
60
Confidence:
85
Support Request:
10
|
needs triage | charmcraft pack fails when building multiple charms consecutively with mismatching platforms, incorrectly reusing a managed instance from a previous build. Untriaged, no maintainer response. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
55
Complexity:
45
Confidence:
90
Support Request:
10
|
needs triage | Consecutive charmcraft pack commands leak platform state between projects, causing subsequent builds to fail with a platform mismatch error. Regression in 4.2.0. Open, unassigned, awaiting triage. |
Update history
| Date | Change |
|---|---|
| updated |
Related issues
| Issue | Project | State | Summary | Similarity |
|---|---|---|---|---|
| #1104 charmcraft pack on Ubuntu 23.04 (Lunar) fails. | charmcraft | closed | Charmcraft pack failed on Ubuntu 23.04 due to unavailable build environments. PR #1130 addressed the issue but was blocked by an external cloud-images bug. The issue was closed pending upstream resolution. | |
| #2078 `charmcraft clean` does not clean all platforms for charm | charmcraft | open | charmcraft clean only removes LXC containers for platforms currently listed in charmcraft.yaml, leaving stale containers for removed platforms. Reported with repro steps; linked to issue #1338 in Jan 2025, no further activity. |