Experimental offline mode fails with network present
Metadata
Current evaluation
Snapcraft's experimental --offline mode crashes with 'NoneType' object is not subscriptable in snaps.py when network is present, and lacks graceful failover. Reported ~4.8 years ago with no maintainer response; the offline feature was only ever added as a warning-only experimental flag.
Suggested action: close stale
Reason: The issue is 1755 days old with zero comments, no labels, and a deactivated reporter account, and the offline feature it targets was only ever merged as a warning-only experimental flag (PR #3577: 'triggers a warning and performs no actions until offline behavior stabilizes'), while the companion implementation PR #3571 '[WIP] offline' was abandoned and closed unmerged. The code paths in the traceback (build_providers/_snap.py, repo/snaps.py) have been substantially reworked since, so the original problem is no longer reproducible in current versions.
Impact:
25
Quick Win:
11.25
Staleness:
90
Complexity:
55
Confidence:
68
Support Request:
10
Issue body
The experimental offline mode in snapcraft does not work as intended, and does not have a graceful failover.
How to reproduce:
Ubuntu 18.04 system (and also in some cases 20.04)
Run snapcraft --offline (with lxd or multipass) on any snapcraft.yaml
The run will fail with:
Sorry, an error occurred in Snapcraft:
'NoneType' object is not subscriptable
We would appreciate it if you anonymously reported this issue.
Complete trace:
Traceback (most recent call last):
File "/snap/snapcraft/6954/bin/snapcraft", line 8, in <module>
sys.exit(run())
File "/snap/snapcraft/6954/lib/python3.8/site-packages/click/core.py", line 1137, in __call__
return self.main(*args, **kwargs)
File "/snap/snapcraft/6954/lib/python3.8/site-packages/click/core.py", line 1062, in main
rv = self.invoke(ctx)
File "/snap/snapcraft/6954/lib/python3.8/site-packages/click/core.py", line 1646, in invoke
super().invoke(ctx)
File "/snap/snapcraft/6954/lib/python3.8/site-packages/click/core.py", line 1404, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/snap/snapcraft/6954/lib/python3.8/site-packages/click/core.py", line 763, in invoke
return __callback(*args, **kwargs)
File "/snap/snapcraft/6954/lib/python3.8/site-packages/click/decorators.py", line 26, in new_func
return f(get_current_context(), *args, **kwargs)
File "/snap/snapcraft/6954/lib/python3.8/site-packages/snapcraft/cli/_runner.py", line 130, in run
snap_command.invoke(ctx)
File "/snap/snapcraft/6954/lib/python3.8/site-packages/click/core.py", line 1404, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/snap/snapcraft/6954/lib/python3.8/site-packages/click/core.py", line 763, in invoke
return __callback(*args, **kwargs)
File "/snap/snapcraft/6954/lib/python3.8/site-packages/snapcraft/cli/lifecycle.py", line 387, in snap
_execute(steps.PRIME, parts=tuple(), pack_project=True, output=output, **kwargs)
File "/snap/snapcraft/6954/lib/python3.8/site-packages/snapcraft/cli/lifecycle.py", line 125, in _execute
with build_provider_class(
File "/snap/snapcraft/6954/lib/python3.8/site-packages/snapcraft/internal/build_providers/_base_provider.py", line 87, in __enter__
self.create()
File "/snap/snapcraft/6954/lib/python3.8/site-packages/snapcraft/internal/build_providers/_lxd/_lxd.py", line 284, in create
self.launch_instance()
File "/snap/snapcraft/6954/lib/python3.8/site-packages/snapcraft/internal/build_providers/_base_provider.py", line 263, in launch_instance
self._setup_snapcraft()
File "/snap/snapcraft/6954/lib/python3.8/site-packages/snapcraft/internal/build_providers/_lxd/_lxd.py", line 481, in _setup_snapcraft
super()._setup_snapcraft()
File "/snap/snapcraft/6954/lib/python3.8/site-packages/snapcraft/internal/build_providers/_base_provider.py", line 508, in _setup_snapcraft
snap_injector.apply()
File "/snap/snapcraft/6954/lib/python3.8/site-packages/snapcraft/internal/build_providers/_snap.py", line 392, in apply
snap.push_host_snap(file_pusher=self._file_pusher)
File "/snap/snapcraft/6954/lib/python3.8/site-packages/snapcraft/internal/build_providers/_snap.py", line 141, in push_host_snap
host_snap_repo.local_download(
File "/snap/snapcraft/6954/lib/python3.8/site-packages/snapcraft/internal/repo/snaps.py", line 181, in local_download
if self.has_assertions():
File "/snap/snapcraft/6954/lib/python3.8/site-packages/snapcraft/internal/repo/snaps.py", line 152, in has_assertions
return not self.get_local_snap_info()["revision"].startswith("x")
TypeError: 'NoneType' object is not subscriptable
Expected behavior:
1. If snapcraft --offline is run and there is network and NO cached assets exist, it should inform the user that it needs to pull the assets from the network the first time.
2. If snapcraft -offline is run and there is network and cached assets, it should run as though there is no network; and there should be no errors.
3. If snapcraft --offline is run and there is no network and no cached assets, it should inform the user that it cannot complete the task as there are no available assets that can be retrieved.
4. If snapcraft --offline is run and there is no network and but there are cached assets, it should complete normally.
Also, if snapcraft is run without offline mode (not specified) and there is no network, it should check for network status first before trying to launch the container, as the container startup will time out (unspecified) but this behavior cannot be distinguished from: a) slow network b) slow vm/container behavior where it can take a long time (minutes) for the vm/container to start.
Evaluation history
| Date | Model | Scores | Action | Summary |
|---|---|---|---|---|
| qwen/qwen3.8-27b |
Impact:
25
Quick Win:
11.25
Staleness:
90
Complexity:
55
Confidence:
68
Support Request:
10
|
close stale | Snapcraft's experimental --offline mode crashes with 'NoneType' object is not subscriptable in snaps.py when network is present, and lacks graceful failover. Reported ~4.8 years ago with no maintainer response; the offline feature was only ever added as a warning-only experimental flag. | |
| qwen/qwen3.6-35b-a3b |
Staleness:
95
Complexity:
40
Confidence:
90
Support Request:
15
|
close stale | Experimental offline mode crashes with a NoneType error when network is present. Issue is 4.7 years old, has zero comments, and targets outdated Ubuntu versions. | |
| qwen/qwen3.6-35b-a3b |
Staleness:
95
Complexity:
45
Confidence:
90
Support Request:
15
|
close stale | Experimental offline mode crashes with a TypeError when network is present but assets aren't cached. Issue is 4.5 years old, has zero maintainer interaction, and targets an outdated snapcraft version. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
95
Complexity:
45
Confidence:
90
Support Request:
10
|
close stale | Experimental offline mode crashes with a TypeError when network is present. The issue is 4.5 years old, has zero comments, and lacks maintainer engagement, indicating the feature or codebase has likely changed significantly. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
98
Complexity:
45
Confidence:
80
Support Request:
10
|
close stale | Experimental offline mode in snapcraft crashes with a TypeError when network is present but assets aren't cached. Issue is 4.6 years old with no maintainer response or activity. |
Update history
No update history recorded yet.
Related work
-
Related To:
canonical/snapcraft#3577
(confidence 80%)
Merged PR that added the experimental --offline CLI flag; it only warns and performs no actions, so the offline behavior described in this issue was never actually implemented.
-
Related To:
canonical/snapcraft#3571
(confidence 70%)
Companion '[WIP] offline' PR that was abandoned and closed without review or merge, indicating the offline feature work was dropped.
Related issues
| Issue | Project | State | Summary | Similarity |
|---|---|---|---|---|
| #3577 cli: add experimental --offline option (CRAFT-480) | snapcraft | merged | Merged into master, adding an experimental --offline CLI flag to Snapcraft. The flag currently triggers a warning and performs no actions until offline behavior stabilizes. Approved by two reviewers and passed CI checks. |