ワークフロー内でアクセスできるコンテキストは決まっている

Workflow key Context
run-name github, inputs, vars
concurrency github, inputs, vars
env github, secrets, inputs, vars
jobs.<job_id>.concurrency github, needs, strategy, matrix, inputs, vars
jobs.<job_id>.container github, needs, strategy, matrix, vars, inputs
jobs.<job_id>.container.credentials github, needs, strategy, matrix, env, vars, secrets, inputs
jobs.<job_id>.container.env.<env_id> github, needs, strategy, matrix, job, runner, env, vars, secrets, inputs
jobs.<job_id>.container.image github, needs, strategy, matrix, vars, inputs
jobs.<job_id>.continue-on-error github, needs, strategy, vars, matrix, inputs
jobs.<job_id>.defaults.run github, needs, strategy, matrix, env, vars, inputs
jobs.<job_id>.env github, needs, strategy, matrix, vars, secrets, inputs
jobs.<job_id>.environment github, needs, strategy, matrix, vars, inputs
jobs.<job_id>.environment.url github, needs, strategy, matrix, job, runner, env, vars, steps, inputs
jobs.<job_id>.if github, needs, vars, inputs
jobs.<job_id>.name github, needs, strategy, matrix, vars, inputs
jobs.<job_id>.outputs.<output_id> github, needs, strategy, matrix, job, runner, env, vars, secrets, steps, inputs
jobs.<job_id>.runs-on github, needs, strategy, matrix, vars, inputs
jobs.<job_id>.secrets.<secrets_id> github, needs, strategy, matrix, secrets, inputs, vars
jobs.<job_id>.services github, needs, strategy, matrix, vars, inputs
jobs.<job_id>.services.<service_id>.credentials github, needs, strategy, matrix, env, vars, secrets, inputs
jobs.<job_id>.services.<service_id>.env.<env_id> github, needs, strategy, matrix, job, runner, env, vars, secrets, inputs
jobs.<job_id>.steps.continue-on-error github, needs, strategy, matrix, job, runner, env, vars, secrets, steps, inputs
jobs.<job_id>.steps.env github, needs, strategy, matrix, job, runner, env, vars, secrets, steps, inputs
jobs.<job_id>.steps.if github, needs, strategy, matrix, job, runner, env, vars, steps, inputs
jobs.<job_id>.steps.name github, needs, strategy, matrix, job, runner, env, vars, secrets, steps, inputs
jobs.<job_id>.steps.run github, needs, strategy, matrix, job, runner, env, vars, secrets, steps, inputs
jobs.<job_id>.steps.timeout-minutes github, needs, strategy, matrix, job, runner, env, vars, secrets, steps, inputs
jobs.<job_id>.steps.with github, needs, strategy, matrix, job, runner, env, vars, secrets, steps, inputs
jobs.<job_id>.steps.working-directory github, needs, strategy, matrix, job, runner, env, vars, secrets, steps, inputs
jobs.<job_id>.strategy github, needs, vars, inputs
jobs.<job_id>.timeout-minutes github, needs, strategy, matrix, vars, inputs
jobs.<job_id>.with.<with_id> github, needs, strategy, matrix, inputs, vars
on.workflow_call.inputs.<inputs_id>.default github, inputs, vars
on.workflow_call.outputs.<output_id>.value github, jobs, vars, inputs

ステップ内の実行条件でシークレットを参照した場合

steps内のif条件 (jobs.<job_id>.steps.if) でsecretsを参照した場合、

name: Test
on:
  push:
    branches:
      - 'test'
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - name: Echo
        if: secrets.TEST != ''
        run: echo test

ワークフローの解析時にエラーになる。

The workflow is not valid. .github/workflows/test.yml (Line: 14, Col: 13): Unrecognized named-value: 'secrets'.
Located at position 1 within expression: secrets.TEST != ''

ステップ内の実行条件で環境変数を参照した場合

steps内のenvでsecretsを参照した変数を定義してif条件ではenvを参照した場合、

name: Test
on:
  push:
    branches:
      - 'test'
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - name: Echo
        env:
          test: $
        if: env.test != ''
        run: echo test

シークレットにTESTが定義されていないとジョブは作成されるがステップは実行されない。

ジョブ内の実行条件でリポジトリ変数を参照した場合

jobs内のif条件 (jobs.<job_id>.if) でvarsを参照した場合、

name: Test
on:
  push:
    branches:
      - 'test'
jobs:
  test:
    runs-on: ubuntu-latest
    if: vars.TEST != ''
    steps:
      - name: Echo
        run: echo test

リポジトリ変数TESTが定義されていないとジョブは実行されない（Skippedで作成はされる）。