When using combined tag@digest references (e.g., nginx:1.21@sha256:abc...),
Docker does NOT store the tag in RepoTags. It only stores the digest in
RepoDigests. The previous implementation required BOTH to match, which
always failed because RepoTags was empty.
This caused docker_container to pull the image on every run even when
the image with the correct digest already existed locally, breaking
idempotency.
The fix: When a digest is specified, match by digest only since it's the
authoritative identifier. The tag is informational for human readability.
Real-world example from docker image inspect:
"RepoTags": [], # Empty when pulled by digest\!
"RepoDigests": ["portainer/portainer-ee@sha256:7ecf2008..."]
Updated tests to reflect the correct behavior:
- test_empty_repo_tags_matches_by_digest (the critical fix case)
- test_combined_tag_digest_matches_even_if_tag_differs
- test_multiple_tags_irrelevant_for_combined
The parse_repository_tag fix alone is not sufficient because Docker stores
RepoTags and RepoDigests separately. When looking up an image with combined
tag@digest (e.g., nginx:1.21@sha256:abc...), the _image_lookup function must
split the combined format and match BOTH RepoTags (for the tag) AND
RepoDigests (for the digest).
Docker stores:
- RepoTags: ["nginx:1.21"]
- RepoDigests: ["nginx@sha256:abc..."]
But NEVER stores the combined format. The previous code would construct:
- lookup = "nginx:1.21@sha256:abc..." (never matches RepoTags)
- lookup_digest = "nginx@1.21@sha256:abc..." (never matches RepoDigests)
This fix:
1. Adds filter_images_by_tag() helper function to _util.py to avoid code
duplication between _common.py and _common_api.py
2. Detects combined tag@digest format in the tag parameter
3. Splits into tag_part and digest_part
4. Constructs proper lookups for both RepoTags and RepoDigests
5. Requires BOTH to match for successful image lookup
Without this fix, image_label_mismatch: ignore fails because the image
cannot be found, resulting in no image labels being included in expected
labels comparison.
Includes comprehensive unit tests in test__util.py covering all scenarios
including edge cases for multiple @ symbols and empty tag parts.
* Remove __metaclass__ = type.
for i in $(grep -REl '__metaclass__ = type' plugins/ tests/); do
sed -e '/^__metaclass__ = type/d' -i $i;
done
* Remove super arguments, and stop inheriting from object.
* Adjust all __future__ imports:
for i in $(grep -REl "__future__.*absolute_import" plugins/ tests/); do
sed -e 's/from __future__ import .*/from __future__ import annotations/g' -i $i;
done
* Remove all UTF-8 encoding specifications for Python source files:
for i in $(grep -REl '[-][*]- coding: utf-8 -[*]-' plugins/ tests/); do
sed -e '/^# -\*- coding: utf-8 -\*-/d' -i $i;
done
* Reformat.
* Make all doc fragments, module utils, and plugin utils private.
* Remove some unused and no longer needed imports.
This hopefully also fixes the CI issues, which do not happen locally for me...
* Fix formatting.
* Try to make CI happy, again.
* Fix imports.
* Lint.
