The prime step uses the install dir when creating a list of migrateable filesets
Metadata
Current evaluation
craft-parts prime step computes migratable filesets from the install dir instead of the stage dir, failing when stage removes a file prime includes. A one-line fix was proposed but breaks overlay cleaning tests; blocked on defining overlay cleaning semantics.
Suggested action: keep open
Reason: Maintainers actively triaged this: @sergiusens confirmed the fileset should be built from staged content, and @mr-cal's 2025-06-23 comment shows the proposed fix breaks overlay-cleaning integration tests (test_lifecycle_overlay.py#L292) and the work is explicitly blocked on documenting overlay cleaning behavior. I verified the buggy line (part_install_dir in _builtin_prime) is still present at current HEAD, so the issue remains applicable and should stay open pending that architectural decision.
Impact:
50
Quick Win:
14.0
Staleness:
58
Complexity:
72
Confidence:
82
Support Request:
0
Issue body
### Bug Description
craft-parts will fail if a `stage` and `prime` are defined for a part and `stage` removes a file.
This can be fixed by changing [this line](https://github.com/canonical/craft-parts/blob/cdcc9dbc76e5fcf352a9744f1d1c74cfab6c15e5/craft_parts/executor/step_handler.py#L243):
```diff
diff --git a/craft_parts/executor/step_handler.py b/craft_parts/executor/step_handler.py
index c88b409..29e6ef8 100644
--- a/craft_parts/executor/step_handler.py
+++ b/craft_parts/executor/step_handler.py
@@ -240,7 +240,7 @@ class StepHandler:
else:
files, dirs = filesets.migratable_filesets(
- prime_fileset, str(self._part.part_install_dir)
+ prime_fileset, str(self._part.stage_dir)
)
files, dirs = migrate_files(
files=files,
```
I don't know if this is on purpose, but it has been like this since it was first added to craft-parts [here](https://github.com/canonical/craft-parts/pull/59/files#diff-8b05be16f7434251a31499a62b63d4f9f2962efd02f3896a9308cbc3ab034dcfR157).
source: https://github.com/canonical/snapcraft/issues/4835 from @dilyn-corner
### To Reproduce
1. Create the filetree:
```
└── src
└── foo
└── bar
├── baz
├── buzz
└── fizz
```
2. Create and run the python script:
```python
import logging
import yaml
import craft_parts
from craft_parts import LifecycleManager, Step
logging.basicConfig(level=logging.DEBUG)
parts_yaml = """
parts:
hello:
plugin: dump
source: src/
stage:
- -foo/bar/baz
prime:
- foo/bar
"""
parts = yaml.safe_load(parts_yaml)
lcm = LifecycleManager(
parts,
application_name="example",
cache_dir=".",
)
with lcm.action_executor() as aex:
aex.execute(lcm.plan(Step.PRIME))
```
### part yaml
_No response_
### Relevant log output
```shell
DEBUG:craft_parts.utils.os_utils:is_snap: False, SNAP_NAME set to None
DEBUG:craft_parts.infos:Setting target machine to x86_64
DEBUG:craft_parts.sources.local_source:ignore patterns: []
INFO:craft_parts.executor.executor:Installing build-packages
DEBUG:craft_parts.executor.executor:verify plugin environment for part 'hello'
DEBUG:craft_parts.sequencer:process hello:1
DEBUG:craft_parts.sequencer:add action hello:1(0)
DEBUG:craft_parts.sequencer:process hello:3
DEBUG:craft_parts.sequencer:add action hello:3(0)
DEBUG:craft_parts.sequencer:process hello:4
DEBUG:craft_parts.sequencer:add action hello:4(0)
DEBUG:craft_parts.sequencer:process hello:5
DEBUG:craft_parts.sequencer:add action hello:5(0)
DEBUG:craft_parts.executor.executor:execute action hello:Action(part_name='hello', step=Step.PULL, action_type=ActionType.RUN, reason=None, project_vars=None, properties=ActionProperties(changed_files=None, changed_dirs=None))
DEBUG:craft_parts.executor.executor:execute action hello:Action(part_name='hello', step=Step.BUILD, action_type=ActionType.RUN, reason=None, project_vars=None, properties=ActionProperties(changed_files=None, changed_dirs=None))
DEBUG:craft_parts.state_manager.states:load state file: /home/developer/dev/craft-parts-examples/prime-fileset-from-stage-dir/parts/hello/state/pull
DEBUG:craft_parts.executor.part_handler:remove directory /home/developer/dev/craft-parts-examples/prime-fileset-from-stage-dir/parts/hello/build
DEBUG:craft_parts.executor.step_handler:Executing PosixPath('/home/developer/dev/craft-parts-examples/prime-fileset-from-stage-dir/parts/hello/run/build.sh')
+ cp --archive --link --no-dereference . /home/developer/dev/craft-parts-examples/prime-fileset-from-stage-dir/parts/hello/install
DEBUG:urllib3.connectionpool:http://localhost:None "GET /v2/snaps HTTP/1.1" 200 None
DEBUG:craft_parts.executor.executor:execute action hello:Action(part_name='hello', step=Step.STAGE, action_type=ActionType.RUN, reason=None, project_vars=None, properties=ActionProperties(changed_files=None, changed_dirs=None))
DEBUG:craft_parts.executor.executor:execute action hello:Action(part_name='hello', step=Step.PRIME, action_type=ActionType.RUN, reason=None, project_vars=None, properties=ActionProperties(changed_files=None, changed_dirs=None))
Traceback (most recent call last):
File "/home/developer/dev/craft-parts/craft_parts/utils/file_utils.py", line 141, in link
os.link(source_path, destination, follow_symlinks=False)
FileNotFoundError: [Errno 2] No such file or directory: '/home/developer/dev/craft-parts-examples/prime-fileset-from-stage-dir/stage/foo/bar/baz' -> '/home/developer/dev/craft-parts-examples/prime-fileset-from-stage-dir/prime/foo/bar/baz'
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/home/developer/dev/craft-parts-examples/prime-fileset-from-stage-dir/main.py", line 29, in <module>
aex.execute(lcm.plan(Step.PRIME))
File "/home/developer/dev/craft-parts/craft_parts/executor/executor.py", line 327, in execute
self._executor.execute(actions, stdout=stdout, stderr=stderr)
File "/home/developer/dev/craft-parts/craft_parts/executor/executor.py", line 137, in execute
self._run_action(act, stdout=stdout, stderr=stderr)
File "/home/developer/dev/craft-parts/craft_parts/executor/executor.py", line 214, in _run_action
handler.run_action(action, stdout=stdout, stderr=stderr)
File "/home/developer/dev/craft-parts/craft_parts/executor/part_handler.py", line 170, in run_action
state = handler(step_info, stdout=stdout, stderr=stderr)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/developer/dev/craft-parts/craft_parts/executor/part_handler.py", line 407, in _run_prime
contents = self._run_step(
^^^^^^^^^^^^^^^
File "/home/developer/dev/craft-parts/craft_parts/executor/part_handler.py", line 491, in _run_step
return step_handler.run_builtin()
^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/developer/dev/craft-parts/craft_parts/executor/step_handler.py", line 108, in run_builtin
return handler()
^^^^^^^^^
File "/home/developer/dev/craft-parts/craft_parts/executor/step_handler.py", line 245, in _builtin_prime
files, dirs = migrate_files(
^^^^^^^^^^^^^^
File "/home/developer/dev/craft-parts/craft_parts/executor/migration.py", line 123, in migrate_files
file_utils.link_or_copy(
File "/home/developer/dev/craft-parts/craft_parts/utils/file_utils.py", line 98, in link_or_copy
link(source, destination, follow_symlinks=follow_symlinks)
File "/home/developer/dev/craft-parts/craft_parts/utils/file_utils.py", line 143, in link
raise errors.CopyFileNotFound(source) from err
craft_parts.errors.CopyFileNotFound: Failed to copy '/home/developer/dev/craft-parts-examples/prime-fileset-from-stage-dir/stage/foo/bar/baz': no such file or directory.
```
Evaluation history
| Date | Model | Scores | Action | Summary |
|---|---|---|---|---|
| qwen/qwen3.8-27b |
Impact:
50
Quick Win:
14.0
Staleness:
58
Complexity:
72
Confidence:
82
Support Request:
0
|
keep open | craft-parts prime step computes migratable filesets from the install dir instead of the stage dir, failing when stage removes a file prime includes. A one-line fix was proposed but breaks overlay cleaning tests; blocked on defining overlay cleaning semantics. | |
| qwen/qwen3.6-35b-a3b |
Staleness:
75
Complexity:
85
Confidence:
85
Support Request:
0
|
keep open | Bug where prime step incorrectly uses install dir instead of stage dir for fileset migration, causing failures when stage removes files. Currently blocked on defining overlay cleaning behavior after a proposed fix broke integration tests. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
75
Complexity:
80
Confidence:
85
Support Request:
10
|
keep open | Bug where prime step incorrectly uses install dir for migratable filesets, causing failures when stage removes files. Currently blocked by maintainer pending documentation of overlay cleaning behavior. | |
| qwen3.6-35b-a3b-mtp-q6 |
Staleness:
65
Complexity:
60
Confidence:
90
Support Request:
0
|
keep open | Bug where prime step uses install dir instead of stage dir for fileset migration, failing when stage removes files. Proposed fix breaks overlay cleaning tests. Blocked until overlay cleaning behavior is documented. |
Update history
No update history recorded yet.
Related work
-
Related To:
canonical/snapcraft#4835
(confidence 85%)
Cited in the issue body as the upstream source report from which this craft-parts bug was extracted.
Related issues
No related issues found above the similarity threshold.