action.yml

name: "Check file"
description: "Check file for expected changes."
inputs:
  file:
    description: "File to search."
    required: true
  search:
    description: "Grep pattern to search."
    required: true
runs:
  using: composite
  steps:
    - shell: bash
      env:
        FILE: ${{ inputs.file }}
        SEARCH: ${{ inputs.search }}
      run: |
        echo "Check that all required env variables are set"
        if [ -z "$FILE" ]
        then
          echo "FILE is unset or set to the empty string"
          exit 1
        fi
        if [ -z "$SEARCH" ]
        then
          echo "SEARCH is unset or set to the empty string"
          exit 1
        fi

        # Make sure to escape your backslashes => \\ <= in YAML
        # So that its still a single \ in bash

        echo "Check that $FILE includes $SEARCH"
        if grep --perl-regexp "$SEARCH" -- $FILE
        then
          echo "Found $SEARCH in $FILE"
        else
          echo "Missing $SEARCH in $FILE"
          echo "----------------"
          echo "$(cat $FILE)"
          exit 204  # We're sending a weird code so it looks different from other "failures"
        fi