Can't use the value of command in GitHub Actions

Question

I tried merging dev branch to stage branch every 5 minutes, using GitHub Actions...

But it didn't work.

name: Auto merge dev2stage

on:
  schedule:
    - cron: "*/5 * * * *"
  push:
    branches:
      - dev

jobs:
  create-pullrequest-and-merge:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v2
        with:
          ref: dev
      - name: dev2stage
        run: |
          PULL_REQUEST_VALUE=$(gh pr create -B stage -t dev2stage -b "")
          gh pr merge $PULL_REQUEST_VALUE

$(gh pr create -B stage -t dev2stage -b "")

The command fails, if there were other pull request from the same base branch. Otherwise, it returns the value of the pull request URI.

I could not store the URI of the pull request. Why not does this script work?

Answer 1

Finally I solved this problem with this.

name: Auto merge dev2stage

on:
  schedule:
    - cron: "0 15 * * *"

jobs:
  auto-merge-dev2stage:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v2
        with:
          ref: dev
      - name: ??????Create Pull Request dev2stage
        id: create-pull-request
        env:
          GH_TOKEN: ${{ secrets.AUTO_DEP_TOKEN }}
        run: |
          PULL_REQUEST_URI=$(gh pr create -B stage -t ??????dev2stage -l 'auto merge' -b "")
          echo "::set-output name=PULL_REQUEST_URI::$PULL_REQUEST_URI"
      - name: ??????Merge Pull Request dev2stage
        env:
          GH_TOKEN: ${{ secrets.AUTO_DEP_TOKEN }}
        run: |
          gh pr merge ${{steps.create-pull-request.outputs.PULL_REQUEST_URI}} --merge