Document supported checksum digest algorithm

[gilbertbw]

Is this a docs issue?

• [X] My issue is about the documentation content or website

Type of issue

I can't find what I'm looking for

Description

The --checksum option for the ADD command does not indicate what digests are supported.

Location

https://docs.docker.com/engine/reference/builder/

Suggestion

Document the digests that are supported. n.b. I could not find the relevant source code for this.

[fcharron]

I'd add to better document the error you get when the digest algorithm is unsupported. I tried ADD --checksum:md5 and the error I was getting from a docker compose build command was "unsupported digest algorithm", which IMO is not very clear. I didn't even know it was about the ADD command, and I was digging around the image digest for a good bit before thinking of looking at the ADD command.

[docker-robot[bot]]

There hasn't been any activity on this issue for a long time. If the problem is still relevant, mark the issue as fresh with a /remove-lifecycle stale comment. If not, this issue will be closed in 14 days. This helps our maintainers focus on the active issues.

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/lifecycle stale

[thiagomarafeli]

I believe this is really needed! It's not clear which algorithms are supported

[gilbertbw]

/remove-lifecycle stale This is still not documented