if-condition.md

[DRAFT] The if condition

The following patterns are interpreted as a string thus always equal to true.

if: |
  ${{ ... }}

if: >
  ${{ ... }}

This example runs on both Issue and Pull Request comments.

on:
  issue_comment:

jobs:
  test:
    if: |
      ${{ github.event.issue.pull_request }}
    runs-on: ubuntu-latest
    steps:
      - run: echo Hello, world!

The next one, however, runs only on Pull Request comments (notice the absence of ${{ ... }}).

on:
  issue_comment:

jobs:
  test:
    if: |
      github.event.issue.pull_request
    runs-on: ubuntu-latest
    steps:
      - run: echo Hello, world!

So it is safe to use if:

• without ${{ ... }}
• without | and >
• with >-

Further research

What are the other ways an expression in the if condition can be misinterpreted? Probably, the https://yaml.org/spec/1.2.2/ specification will be helpful.