::set-output does not document that value cannot contain newlines

[jsoref]

What article on docs.github.com is affected?

https://docs.github.com/en/actions/reference/workflow-commands-for-github-actions#setting-an-output-parameter

What part(s) of the article would you like to see updated?

It should indicate that value cannot contain newlines.

Additional information

https://github.community/t/use-ssh-key-from-secret-in-output-set-output/141071/2
https://github.community/t/set-output-truncates-multiline-strings/16852/3

Content design plan

• Document the solution from https://github.community/t/set-output-truncates-multiline-strings/16852/3 in https://docs.github.com/en/actions/reference/workflow-commands-for-github-actions#setting-an-output-parameter.

[janiceilene]

Thanks for opening an issue @jsoref! I'll triage this for the team to take a look 👀

[lecoursen]

Thanks @jsoref! The solution in https://github.community/t/set-output-truncates-multiline-strings/16852/3 would be good to document. You or anyone else is welcome to do so!

[jsoref]

@lecoursen: I found the solution so icky that I didn't want to be blamed for documenting it (c.f. https://github.community/t/set-output-truncates-multiline-strings/16852/5), hence just filing a bug asking that it be documented as opposed to writing the documentation.

That said, once it is officially documented, I'll be quite happy to point to it / rely on it to work 😄 .

[jsoref]

Sigh

[mark-mxwl]

Hi @jsoref and @lecoursen!

It seems that in the time since this issue was posted, it has been solved with the introduction of GITHUB env files. Substituting set-output with $GITHUB_OUTPUT, in conjunction with a delimiter, allows for multiline output. These options are already documented in the two sections immediately preceding the one linked to this issue.

Ref closed issue #21529 with regard to using a delimiter for multiline output.

As there is a planned deprecation for the set-output command, I would recommend that this issue be marked as closed.