bash gets built with a /bin/bash that is missing the executable bit
Metadata
Current evaluation
Staging bash+quilt in a classic core24 snap produces a non-executable bin/bash: craft-parts' normalize.py _try_copy_local uses shutil.copyfile, which drops file modes. Confirmed root cause, no fix landed.
Suggested action: keep open
Reason: Reproducible with a minimal snapcraft.yaml, and @lengau traced it precisely to craft_parts/packages/normalize.py#L148-L157, which I verified still calls shutil.copyfile() — content-only, so the 0755 mode of /usr/bin/bash is lost (the sibling `elif path.exists(): _fix_filemode(path)` branch is skipped for symlinks, so nothing repairs it). The fix is a one-line switch to shutil.copy2/copystat plus an existing snapcraft spread test asserting the mode. Inactivity is expected because the defect lives in craft-parts, not snapcraft; that is a cross-repo ownership reason for the silence, not evidence the bug is obsolete. Kept open rather than closed because nothing in the source shows resolution.
Evaluated by: mr-cal-bot
Impact:
45
Quick Win:
33
Complexity:
15
Confidence:
88
Actionability:
85
Issue body
### Bug Description
If I stage the `bash` and `quilt` packages in a part in a classic snap, then the snap gets built with a `bin/bash` file that is not executable. Subsequent attempts to use it fail.
### To Reproduce
On a fresh Noble VM:
```
sudo snap install --classic snapcraft
# installs 8.4.3 (12823)
mkdir -p demo/snap
cat > demo/snap/snapcraft.yaml <<EOT
name: demo
version: 1
summary: demo
description: demo
confinement: classic
grade: devel
base: core24
apps:
demo:
command: usr/bin/bash
parts:
demo:
build-attributes: [enable-patchelf]
plugin: nil
stage-packages: [bash, quilt]
EOT
cd demo
snapcraft build --destructive-mode
```
Expected result: `parts/demo/install/bin/bash` is executable, and this passes through to the final snap (if you continue you should also see it in `prime/bin/bash` as executable, etc).
Actual result: `parts/demo/install/bin/bash` is not executable and this passes through to the final snap. Then scripts that try to use it fail.
### Environment
Ubuntu 24.04 cloud image, snapcraft in destructive mode. Snapcraft snap 8.4.3 (12823).
### snapcraft.yaml
```yaml
name: demo
version: 1
summary: demo
description: demo
confinement: classic
grade: devel
base: core24
apps:
demo:
command: usr/bin/bash
parts:
demo:
build-attributes: [enable-patchelf]
plugin: nil
stage-packages: [bash, quilt]
```
### Relevant log output
```shell
2024-10-13 13:12:26.879 Building demo
2024-10-13 13:12:26.893 execute action demo:Action(part_name='demo', step=Step.BUILD, action_type=ActionType.RUN, reason=None, project_vars=None, properties=ActionProperties(changed_files=None, changed_dirs=None))
2024-10-13 13:12:26.894 load state file: /home/ubuntu/demo/parts/demo/state/pull
2024-10-13 13:12:28.158 fix artifacts: unpack_dir='/home/ubuntu/demo/parts/demo/install'
2024-10-13 13:12:28.175 fix symlink: path='/home/ubuntu/demo/parts/demo/install/usr/share/quilt/compat/bash', unpack_dir='/home/ubuntu/demo/parts/demo/install', root='/home/ubuntu/demo/parts/demo/install/usr/share/quilt/compat'
2024-10-13 13:12:28.207 fix symlink: target='/home/ubuntu/demo/parts/demo/install/bin/bash'
2024-10-13 13:12:28.207 Copying needed target link from the system: /usr/bin/bash
2024-10-13 13:12:30.039 remove directory /home/ubuntu/demo/parts/demo/build
2024-10-13 13:12:30.041 Executing PosixPath('/home/ubuntu/demo/parts/demo/run/build.sh')
```
### Additional context
The trace output suggests that snapcraft is doing something because `usr/share/quilt/compat/bash` is a symlink. If I drop `quilt` from `stage-packages`, then `bin/bash` isn't created.
I found this when trying to move the git-ubuntu snap to core24. That's complex enough so I came up with a minimal reproducer.
Workaround: I did this:
```
override-stage: |
craftctl default
chmod 755 bin/bash
```
Evaluation history
| Date | Model | Scores | Action | Summary |
|---|---|---|---|---|
| stealth/space-bunny-alpha |
Impact:
45
Quick Win:
33
Complexity:
15
Confidence:
88
Actionability:
85
|
keep open | Staging bash+quilt in a classic core24 snap produces a non-executable bin/bash: craft-parts' normalize.py _try_copy_local uses shutil.copyfile, which drops file modes. Confirmed root cause, no fix landed. | |
| stealth/space-bunny-alpha |
Impact:
38
Quick Win:
14
Complexity:
42
Confidence:
78
Actionability:
62
|
keep open | Staging quilt alongside bash yields a non-executable bin/bash: craft-parts' _try_copy_local uses shutil.copyfile, dropping file modes. Maintainers pinpointed normalize.py; workaround is override-stage chmod. Unfixed. | |
| stealth/space-bunny-alpha |
Impact:
45
Quick Win:
23
Complexity:
35
Confidence:
80
Actionability:
78
|
keep open | Staging bash+quilt in a classic core24 snap yields a non-executable bin/bash (lost mode when craft-parts copies the symlink target); maintainers traced it to craft_parts/packages/normalize.py, still unresolved | |
| qwen/qwen3.6-35b-a3b |
Impact:
70
Quick Win:
39
Complexity:
30
Confidence:
85
Actionability:
80
|
keep open | bash staged via craft-parts loses executable bit when quilt's absolute symlink is resolved, due to shutil.copyfile not preserving permissions | |
| qwen/qwen3.8-27b |
Impact:
45
Quick Win:
32
Staleness:
70
Complexity:
30
Confidence:
70
Support Request:
10
|
keep open | Staging bash+quilt in a classic snap yields a non-executable bin/bash because craft-parts normalize copies the symlink target from the system via shutil.copyfile, dropping the executable bit. Unfixed in craft-parts; reporter has a chmod workaround. | |
| qwen/qwen3.6-35b-a3b |
Staleness:
88
Complexity:
55
Confidence:
75
Support Request:
10
|
close stale | Staging bash and quilt in a classic snap causes /bin/bash to lose its executable bit due to craft-parts symlink normalization. The issue has been inactive for over a year with a provided workaround but no fix. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
95
Complexity:
45
Confidence:
85
Support Request:
15
|
close stale | Staging bash and quilt in a classic snap causes bin/bash to lose its executable bit. Currently inactive for over 630 days with a workaround available. |
Update history
No update history recorded yet.
Related work
-
Blocked By:
canonical/craft-parts
(confidence 90%)
The defect is in craft_parts/packages/normalize.py::_try_copy_local, not snapcraft; fixing it requires an upstream craft-parts change (shutil.copyfile -> copy2/copystat). @lengau and @mr-cal/@cmatsuoka were already pinged about it.
Related issues
No related issues found above the similarity threshold.