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GitHub Actions で真偽値判定の注意点

2022/08/03に公開

GitHub

GitHub Actions

tech

はじめに

GitHub Actions の真偽値判定がややこしかったため、備忘録として残しておきます。

実験

以下のワークフローを実行するとどうなるのでしょうか。

name: expression

on:
  workflow_dispatch:

jobs:
  expression:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        enabled: [ true, false ]

    steps:
      - id: check
        run: echo "::set-output name=enabled::${{ matrix.enabled }}"

      - if: steps.check.outputs.enabled
        name: executed 1
        run: echo "executed 1"

      # ${{ }} 内でなければ、YAML の仕様により `!` は否定演算子ではなく
      # タグとして扱われるため、この記述は構文エラーになってしまう
      # 参考: https://github.com/yaml/yaml-spec
      #
      # - if: !steps.check.outputs.enabled
      #   name: executed 2
      #   run: echo "executed 2"

      - if: ${{ steps.check.outputs.enabled }}
        name: executed 3
        run: echo "executed 3"

      - if: ${{ !steps.check.outputs.enabled }}
        name: executed 4
        run: echo "executed 4"

      - if: steps.check.outputs.enabled == true
        name: executed 5
        run: echo "executed 5"

      - if: steps.check.outputs.enabled != true
        name: executed 6
        run: echo "executed 6"

      - if: steps.check.outputs.enabled == false
        name: executed 7
        run: echo "executed 7"

      - if: steps.check.outputs.enabled != false
        name: executed 8
        run: echo "executed 8"

      - if: steps.check.outputs.enabled == 'true'
        name: executed 9
        run: echo "executed 9"

      - if: steps.check.outputs.enabled != 'true'
        name: executed 10
        run: echo "executed 10"

      - if: steps.check.outputs.enabled == 'false'
        name: executed 11
        run: echo "executed 11"

      - if: steps.check.outputs.enabled != 'false'
        name: executed 12
        run: echo "executed 12"