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Increasing short commit hash length is a breaking change #479
Description
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- I've read the contributing guidelines and wholeheartedly agree
I've found a bug, and:
- The documentation does not mention anything about my problem
- There are no open or closed issues that are related to my problem
Description
#467 increased the default length of the commit hash created by the sha directive
This was released in v5.6.0 which made it immediately apply to everyone whose workflow specified release v5 in their actions.
This change unfortunately broke my workflows, because other parts of our workflows were hard-coded to match the size of the tags created by this action.
Please consider pulling this release and re-releasing it as v6.
Expected behaviour
v5 creates short "sha" tags with 7-character commit hash
Actual behaviour
v5 suddenly creates short "sha" tags with 12-character commit hash
Repository URL
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Workflow run URL
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YAML workflow
- name: Docker image metadata
id: metadata
uses: docker/metadata-action@v5
with:
images: |
${{ steps.ghcr_image_name.outputs.name }}
tags: |
type=ref,event=branch
type=ref,event=pr
type=semver,pattern={{major}}.{{minor}}.{{patch}}
type=sha
- name: Get deployment tag
id: get_deployment_tag
# The following variables are made available to subsequent jobs to be used to find the specific Docker image that was built and pushed by this job.
run: |
echo "deployment_tag=sha-$(echo ${{ github.sha }} | cut -c1-7)" >> $GITHUB_OUTPUT
echo "build_image=${{ steps.ghcr_image_name.outputs.name }}:sha-$(echo ${{ github.sha }} | cut -c1-7)" >> $GITHUB_OUTPUTWorkflow logs
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BuildKit logs
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Reacted by James Estes, Matt Casey, Johannes Edelstam, Mathieu Cabaret, Fabien, Greg Troszak, Jakob Danielsson, Scott Nelson and ApophisLee
Activity
housejester commentedon Nov 19, 2024
Came here to post the same. Good news is that there is the ENV you can set to get it working again, but feels like it could have kept the default until a more major version bump.
Workaround is to add the env to the action:
crazy-max commentedon Nov 19, 2024
I guess in your case it breaks for
deployment_tagandbuild_imagebecause you rely ongithub.shainstead of metadata outputs. I don't think this is a breaking change as you don't rely on metadata outputs imo.You can either enforce commit sha length with
DOCKER_METADATA_SHORT_SHA_LENGTHenv var:Or rely on the actual metadata outputs https://github.com/docker/metadata-action?tab=readme-ov-file#outputs to get a usable tag like
versionwith${{ steps.metadata.outputs.version }}housejester commentedon Nov 19, 2024
In my case, i use a different action for rendering k8s yamls (skaffold...and yeah, i don't like skaffold), and for that tool, I cannot (easily) configure/pass in the sha...it has its own internal opinion about what a short sha is. I get that probably isn't common, but wanted the team to be aware it /is/ breaking peoples flows, and a safer approach would have been to not change a default in a non-major version bump.
crazy-max commentedon Nov 19, 2024
The previous version relying on hardcoded short commit sha to length 7 is a bug on its own as it would be unreliable for huge repositories.
As stated in git documentation: https://git-scm.com/docs/git-rev-parse#Documentation/git-rev-parse.txt---shortltlengthgt
So it defaults to 4 but based on repo size can be higher.
We choose 12 as it seems a good defaults which is what Go modules use when computing untagged dependencies.
crazy-max commentedon Nov 19, 2024
I'm going to set the defaults back to 7 but keep the environment variable for people who want to rely on a higher value.
crazy-max commentedon Nov 19, 2024
Should be good with latest patch release. Let us know if that fixes the issue on your side 🙏
housejester commentedon Nov 19, 2024
Thanks @crazy-max . I've tested and can confirm the latest works w/o the ENV. (i'm planning to keep the ENV specified moving forward, fwiw).
RobinDaugherty commentedon Nov 20, 2024
Thank you @crazy-max!
I agree that increasing the default from 7-characters is desirable. In my case we don't really need the shortened hash, so I took the opportunity to switch to the full length, using:
crazy-max commentedon Nov 4, 2025
Will make commit hash length to 12 the default on next major v6