skip repacking if snap content not changed by cmatsuoka · Pull Request #6342 · canonical/snapcraft

cmatsuoka · 2026-07-14T12:30:53Z

Mediate creation of metadata and asset files to only repack artifacts
if prime or post-prime contents have been changed. This includes
project or part definitions, snap metadata, manifests, hooks, and icon
and desktop files.

I've followed the contribution guidelines.
I've signed the CLA.
I've successfully run make lint && make test.
I've added or updated any relevant documentation.
In documents I changed, I added a meta description if one was missing.
I've updated the relevant release notes.

Mediate creation of metadata and asset files to allow recreation of artifacts only if prime or post-prime content has changed. Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

Copilot

Pull request overview

This PR updates Snapcraft’s packaging flow to avoid repacking artifacts when primed/post-prime contents haven’t meaningfully changed, by mediating generation of metadata and asset files (snap.yaml, component.yaml, manifest, hooks, GUI assets, desktop/icon handling) and relying on craft-application’s conditional repack support.

Changes:

Upgrades craft-application/craft-providers and sets always_repack=False to enable conditional repack behavior.
Refactors snapcraft.services.package.Package to generate package files/assets via mediated writers and change-detection (including manifest comparison that ignores snapcraft-started-at).
Adds extensive unit tests plus a new spread test to validate “skip repack” behavior and asset/hook handling (including executability).

Reviewed changes

Copilot reviewed 11 out of 13 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
uv.lock	Locks upgraded craft-application/craft-providers versions used by the new packaging behavior.
pyproject.toml	Bumps craft-application dependency to enable conditional repack support.
snapcraft/application.py	Disables unconditional repacking via `always_repack=False`.
snapcraft/services/package.py	Core implementation of mediated metadata/assets and conditional repack change detection.
snapcraft/parts/setup_assets.py	Exposes asset helper functions for reuse by the package service.
snapcraft/parts/desktop_file.py	Adds `render()` to allow desktop file rewriting without immediate filesystem writes.
snapcraft/meta/component_yaml.py	Adds `get_metadata()` helper to support mediated component.yaml generation.
tests/unit/services/test_package.py	Adds unit coverage for mediated snap metadata/assets, manifest drift handling, and change detection.
tests/unit/services/test_package_components.py	Extends component packaging tests for mediated assets and hook executability.
tests/unit/parts/test_setup_assets.py	Updates tests to match newly exported setup-assets helper functions.
tests/spread/general/skip-repack/task.yaml	New spread test validating that repacking is skipped when nothing changes.
tests/spread/general/skip-repack/snap/snapcraft.yaml	Spread test snapcraft.yaml fixture for skip-repack scenario.
tests/spread/general/skip-repack/snap/icon.svg	Spread test icon fixture to trigger repacks when modified.

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com> Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

…ct-contents-are-unchanged

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

…ct-contents-are-unchanged

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

lengau · 2026-07-14T23:37:15Z

It's fairly hard to follow the changes in this file. Perhaps this is worth a live review.

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

mr-cal

Looks good overall, but I agree with @lengau that a live review would be useful as I'm also having a hard time understanding the package service.

mr-cal · 2026-07-14T23:42:13Z

+            )
+
    @override
    def pack(self, prime_dir: pathlib.Path, dest: pathlib.Path) -> list[pathlib.Path]:


Can we remove this old pack command now that it's been superseded by _pack()?

Also _pack_components() is dead code too now

mr-cal · 2026-07-15T00:01:25Z

-        for hook in hooks_project_dir.iterdir():
-            meta_dir_hook = hooks_meta_dir / hook.name
-
-            _hardlink_or_copy(hook, meta_dir_hook)


This function is no longer referenced, can you drop it too?

mr-cal · 2026-07-15T00:14:39Z

+
+        return assets
+
+    def _resolve_icon_asset(  # noqa: PLR0911


This function is a near-verbatim copy of finalize_icon() in setup_assets.py, which will be tough to keep the 2 copies in-sync. Can we extract all of resolution logic from finalize_icon into another function to cut down on the duplication?

mr-cal · 2026-07-15T00:20:42Z


+        return assets
+
+    def _get_hook_assets(


I have a similar concern about maintaining duplicated code for this, _get_declared_hooks, and _validate_declared_hook_command_chains. My main concern with duplicated code is that core22 would diverge from core24+.

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

cmatsuoka · 2026-07-15T00:30:47Z

I think this change is too complex. I'm considering treating it as a spike and propose new PRs for each type of mediated metadata or asset file.

…ct-contents-are-unchanged

cmatsuoka · 2026-07-15T14:54:58Z

Split snap.yaml creation as #6349

Copilot AI review requested due to automatic review settings July 14, 2026 12:30

Copilot started reviewing on behalf of cmatsuoka July 14, 2026 12:31 View session

cmatsuoka added 6 commits July 14, 2026 09:31

feat: skip repacking if snap content is not changed

3ff8255

Mediate creation of metadata and asset files to allow recreation of artifacts only if prime or post-prime content has changed. Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

feat: mediate manifest.yaml

e885eb1

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

feat: mediate component.yaml and project copy

0256d4f

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

feat: mediate hook files

fdfde7f

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

feat: mediate creation of icon and desktop assets

c02b3a9

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

chore: reuse existing helpers instead of reimplementing

9993fb3

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

cmatsuoka force-pushed the work/SNAPCRAFT-1364-Skip-repacking-if-artifact-contents-are-unchanged branch from 049b0b5 to 9993fb3 Compare July 14, 2026 12:32

Copilot AI reviewed Jul 14, 2026

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Comment thread snapcraft/services/package.py

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cmatsuoka and others added 9 commits July 14, 2026 12:55

chore: better filtering for hook file creation

6281ff9

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com> Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

chore: handle asset clash issue raised in review

e541acf

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

chore: handle icon retrieval errors

47a34c7

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

chore: update docstring

da83271

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

chore: address linter warnings

7303ca3

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

chore: address linter warnings

d0ae763

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

chore: address linter warnings

f91dfc0

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

chore: address linter warnings

6b466d1

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

chore: address linter warnings

0ac9ce1

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

cmatsuoka marked this pull request as ready for review July 14, 2026 13:41

cmatsuoka requested a review from mr-cal as a code owner July 14, 2026 13:41

cmatsuoka added 3 commits July 14, 2026 11:32

chore: address linter warnings

4a7f0b5

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

chore: address linter warning

a536eb9

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

chore: remove unused methods

b7f8d08

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

cmatsuoka requested a review from lengau July 14, 2026 15:03

cmatsuoka added 5 commits July 14, 2026 16:25

Merge branch 'main' into work/SNAPCRAFT-1364-Skip-repacking-if-artifa…

9ed5ca3

…ct-contents-are-unchanged

chore: address linter warning

a8cf43e

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

chore: fix mediated icon asset error

159cc2d

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

Merge branch 'main' into work/SNAPCRAFT-1364-Skip-repacking-if-artifa…

df7707a

…ct-contents-are-unchanged

chore: address linter warning

f2e8202

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

lengau reviewed Jul 14, 2026

View reviewed changes

chore: handle empty environment variables

bfbbb1e

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

mr-cal reviewed Jul 15, 2026

View reviewed changes

chore: fix icon download issue

a23571c

Signed-off-by: Claudio Matsuoka <claudio.matsuoka@canonical.com>

Merge branch 'main' into work/SNAPCRAFT-1364-Skip-repacking-if-artifa…

71e73ca

…ct-contents-are-unchanged

cmatsuoka marked this pull request as draft July 15, 2026 14:55

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skip repacking if snap content not changed - #6342

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