Conditional operator or function for expression syntax

[StephenCleary]

Describe the enhancement

I'd like some kind of conditional operation added to expression syntax. This can be an actual ternary operator (? :) or a built-in function (e.g., if(<condition>, <true-value>, <false-value>)).

Additional information

There is a workaround: using shell scripts to evaluate the condition, setting step outputs, and having other steps reference those outputs. But it would be much cleaner to have some kind of ternary / if/then/else / conditional branching built in to the expression syntax.

[ylemkimon]

Another alternative syntax could be:

${{ if(condition) }} evaluateIfTrue ${{ else }} evaluateIfFalse ${{ endif }}

like CircleCI.

[ylemkimon]

It seems, although not identical, <condition> && <true-value> || <false-value> works in most cases.

[molszanski]

Syntax: ${{ x && 'ifTrue' || 'ifFalse' }}

fake ternary example

    steps:
      - name: stuff
        env:
          PR_NUMBER_OR_MASTER: ${{ github.event.number == 0 && 'master' ||  format('pr-{0}', github.event.number)  }}

on condition is that your first <true-value> must be true for this to work

[TWiStErRob]

Example use case https://github.com/TWiStErRob/net.twisterrob.gradle/pull/136/files
Related StackOverflow: https://stackoverflow.com/a/68422069/253468

[LaPeste]

The fact that in a year no one said a word about this, means that the team isn't interested in following up on this one?

[nmattia]

A note about the workaround ${{ x && <yes> || <false> }}:

This only works if <yes> isn't the empty string. If <yes> == '' then '' is considered as false, which then evaluates the right hand side of the ||. Just lost ten minutes over this, hope it helps!

[islishude]

Seems that there is already an approach

https://docs.github.com/en/actions/learn-github-actions/expressions#example

env:
  MY_ENV_VAR: ${{ github.ref == 'refs/heads/main' && 'value_for_main_branch' || 'value_for_other_branches' }}

I think this issue can be closed.

[mayank99]

@islishude you can't shouldn't just comment on an issue that hundreds of people have subscribed to, just to say "this can be closed" when your suggested approach (and its limitation) has already been mentioned. see #409 (comment)

[islishude]

Interesting, you saying I can't comment, is the comment illegal?

you can't just comment on an issue that hundreds of people have subscribed to

[TWiStErRob]

It's good to see GitHub embracing the workaround as a stop-gap, they even mention its limitation in the docs @islishude linked.

On one hand it's good they added it, because at least now it's easier to discover, but on the other hand I do hope it doesn't mean they consider ternary "supported".

It would be great to get some official response from GitHub staff. 🤔

[igor-pinchuk]

It's ridiculous that we do not have ternary operator and this issue is 3+ y.o.
Github actions is so silly engineered, will avoid it for any future projects by all means.

[ameknite]

Correct answer for booleans
${{ (condition && 'ifTrue') || (!condition && 'ifFalse') }}

[socketbox]

It's good to see GitHub embracing the workaround as a stop-gap, they even mention its limitation in the docs @islishude linked.

The docs state, "In this example, we're using a ternary operator to set the value of the MY_ENV_VAR environment variable," which is laughable, because there is no ternary operator, just a logical kludge that relies on short-circuit boolean evaluation:

env:
  MY_ENV_VAR: ${{ github.ref == 'refs/heads/main' && 'value_for_main_branch' || 'value_for_other_branches' }}

Great exposition on just why this is a poor solution: https://7tonshark.com/posts/github-actions-ternary-operator/

[github-actions]

Thank you for your interest in the runner application and taking the time to provide your valuable feedback. We kindly ask you to redirect this feedback to the GitHub Community Support Forum which our team actively monitors and would be a better place to start a discussion for new feature requests in GitHub Actions. For more information on this policy please read our contribution guidelines. 😃

[patrickelectric]

Looks more as unsolved than "completed"

[enumag]

Couldn't find an existing thread there so I created one: https://github.com/orgs/community/discussions/75928