[SOLVED] GitHub Actions: How can I specify ref to checkout conditionally?

GitHub Actions: How can I specify ref to checkout conditionally?

I made an optional input to specify branch:

on:
  workflow_dispatch:
    inputs:
      DEPLOYMENT_BRANCH:
        description: branch that needs to be deployed
        type: string
        required: false

... then want to use as a checkout option:

jobs:
  my_job:
    steps:
    - name: Checkout repo
      uses: actions/checkout@v3
      with:
        ref: ${{ inputs.DEPLOYMENT_BRANCH }}

Now, I want to checkout only if the DEPLOYMENT_BRANCH is passed and ignore otherwise. So I came up with this:

- name: Checkout repo
  if: inputs.DEPLOYMENT_BRANCH != ''
  uses: actions/checkout@v3
  with:
    ref: ${{ inputs.DEPLOYMENT_BRANCH }}

Can someone please validate if this is right way to identify undefined DEPLOYMENT_BRANCH or should I use some other variable?

Solution

You can directly pass the input to actions/checkout@v3 with ${{inputs.DEPLOYMENT_BRANCH}}(without any conditionals).

 - name: Checkout repo
   uses: actions/checkout@v3
   with:
     ref: ${{ inputs.DEPLOYMENT_BRANCH }}

This is because from the source code the action will fallback to the default if the ref input evaluate to false.