Documentation for "list" types is incorrect

[coreyti]

Contributing guidelines

• 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

First, thank you for providing this wonderful resource for the community!

Now, I want to point out that the documentation on the README is not correct in that "types" listed as "lists" are not actually YAML lists; instead they are YAML multi-line strings. This might seem like a pedantic nitpick, but it took me some time today to realize what I was doing wrong.

For example, if the builld-args input was actually a list, one might write something like:

with:
  build-args:
    - ARG1: VALUE1
    - ARG2: VALUE2

when, in fact what would be required is:

with:
  build-args: |
    ARG1=VALUE1
    ARG2=VALUE2

The latter (correct usage) is not a YAML "list".

Expected behaviour

The README documentation should not indicate that something is a "ist" when in fact it is a (multi-line) string.

Actual behaviour

When attempting to specify values for fields such as build-args as a list, per the documentation, one will receive an error along the lines of "A sequence was not expected".

Repository URL

No response

Workflow run URL

No response

YAML workflow

# failure:

  uses: docker/build-push-action@v6
  with:
    build-args:
      - REVISION: "${{ steps.determine_tag.outputs.revision }}"

# success:

  uses: docker/build-push-action@v6
  with:
    build-args: |
      REVISION="${{ steps.determine_tag.outputs.revision }}"

Workflow logs

No response

BuildKit logs

Additional info

No response

[coreyti]

I know see that the README states the following:

List type is a newline-delimited string

So, perhaps that should be sufficient (?). When I read that the "type" of something that is written in language X, I tend to expect that type to be what the language defines. So, I found this to be surprising.

[lucasoares]

Took me a while to understand that too. I think it should not use the name "list" haha

[mbuffa]

Encountered the same problem and digged that issue.

I would suggest about using List(*) with the asterisk linking to the note, or something similar so that it catches the eye :)