Incorrect info about expression syntax for if conditionals

[jidicula]

What article on docs.github.com is affected?

https://docs.github.com/en/actions/reference/context-and-expression-syntax-for-github-actions#about-contexts-and-expressions

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

There's a reusable ({% data reusables.github-actions.expression-syntax-if %}) in this document that contains the info:

When you use expressions in an if conditional, you may omit the expression syntax (${{ }}) because GitHub automatically evaluates the if conditional as an expression.

However, I just made a small example run with a job's if conditional like:

post-build:
     runs-on: ubuntu-latest
     needs: build
     if: !startsWith(needs.build.outputs.sha8, needs.build.outputs.short-sha)
     steps:
        # ...

and it failed with a syntax error in the if statement: The workflow is not valid. .github/workflows/release.yml: Unexpected tag '!startsWith(needs.build.outputs.sha8,' (see here).

The run succeeds when the expression is surrounded by ${{}}:

post-build:
     runs-on: ubuntu-latest
     needs: build
     if: ${{!startsWith(needs.build.outputs.sha8, needs.build.outputs.short-sha)}}
     steps:
        # ...

I'd fix this in a PR if I knew where to find the reusable, but it wasn't immediately transparent, so I'm submitting an issue instead. If anyone could point me to where {% data reusables.github-actions.expression-syntax-if %} is defined, I'll happily make a PR with the required changes. It seems that expressions must be explicitly indicated for evaluation if they contain any operators.

Additional information

• Syntax-erroring test run where documentation was false: https://github.com/jidicula/test-actions/actions/runs/496429121
• Permalink to offending if condition with an expression containing the ! operator with no surround ${{}} : https://github.com/jidicula/test-actions/blob/39946fb7867001386eb671c9f84dfc3a7443dedd/.github/workflows/release.yml#L56
• Test run where surrounding if statement expression with ${{}} succeeded without syntax error: jidicula/test-actions@628f8ff
• Permalink to correct syntax if statement with an expression containing a ! operator surrounded by ${{}}: https://github.com/jidicula/test-actions/blob/628f8ffcdc02ae43dec64ad076e3dbd114633836/.github/workflows/release.yml#L56

[welcome]

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[ajsirota]

Reusables are in /data/reusables. Here is that specific one.

[hubwriter]

@jidicula - This is an exemplary docs issue: you've made it very clear what needs changed and why, with supporting evidence. 👍
Many thanks! 😃