workflows: improve scheduled behaviour.

.github/workflows/spdx.yml

@@ -27,14 +27,26 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
           HOMEBREW_GITHUB_API_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
-          git fetch origin master
-          git reset origin/master
-          git checkout -B spdx-update
+          git fetch origin
+
+          BRANCH="spdx-update"
+          echo "::set-output name=branch::${BRANCH}"
+
+          if git ls-remote --exit-code --heads origin "$BRANCH"; then
+            git checkout "$BRANCH"
+            git reset origin/master
+          else
+            git checkout -B "$BRANCH" origin/master
+            BRANCH_EXISTS="1"
+          fi
 
           if brew update-license-data --fail-if-not-changed; then
             git add "$GITHUB_WORKSPACE/Library/Homebrew/data/spdx"
             git commit -m "spdx: update license data." -m "Autogenerated by [a scheduled GitHub Action](https://github.com/Homebrew/brew/blob/master/.github/workflows/spdx.yml)."
             echo "::set-output name=committed::true"
+            if [ -n "$BRANCH_EXISTS" ]; then
+              echo "::set-output name=pull_request::true"
+            fi
           fi
 
       - name: Push commits
@@ -42,11 +54,11 @@ jobs:
         uses: Homebrew/actions/git-try-push@master
         with:
           token: ${{ secrets.HOMEBREW_GITHUB_API_TOKEN }}
-          branch: spdx-update
+          branch: ${{ steps.update.outputs.branch }}
           force: true
 
       - name: Open a pull request
-        if: steps.update.outputs.committed == 'true'
+        if: steps.update.outputs.pull_request == 'true'
         run: hub pull-request --no-edit
         env:
           GITHUB_TOKEN: ${{ secrets.HOMEBREW_GITHUB_API_TOKEN }}

.github/workflows/tapioca.yml

@@ -35,9 +35,18 @@ jobs:
       - name: Update Tapioca definitions
         id: update
         run: |
-          git fetch origin master
-          git reset origin/master
-          git checkout -B tapioca-update
+          git fetch origin
+
+          BRANCH="tapioca-update"
+          echo "::set-output name=branch::${BRANCH}"
+
+          if git ls-remote --exit-code --heads origin "$BRANCH"; then
+            git checkout "$BRANCH"
+            git reset origin/master
+          else
+            git checkout -B "$BRANCH" origin/master
+            BRANCH_EXISTS="1"
+          fi
 
           # TODO: replace with `brew typecheck`
           cd "$GITHUB_WORKSPACE/Library/Homebrew"
@@ -49,6 +58,9 @@ jobs:
             git add "$GITHUB_WORKSPACE/Library/Homebrew/sorbet"
             git commit -m "sorbet: update RBI files using Tapioca." -m "Autogenerated by [a scheduled GitHub Action](https://github.com/Homebrew/brew/blob/master/.github/workflows/tapioca.yml)."
             echo "::set-output name=committed::true"
+            if [ -n "$BRANCH_EXISTS" ]; then
+              echo "::set-output name=pull_request::true"
+            fi
           fi
 
       - name: Push commits
@@ -56,11 +68,11 @@ jobs:
         uses: Homebrew/actions/git-try-push@master
         with:
           token: ${{ secrets.HOMEBREW_GITHUB_API_TOKEN }}
-          branch: tapioca-update
+          branch: ${{ steps.update.outputs.branch }}
           force: true
 
       - name: Open a pull request
-        if: steps.update.outputs.committed == 'true'
+        if: steps.update.outputs.pull_request == 'true'
         run: hub pull-request --no-edit
         env:
           GITHUB_TOKEN: ${{ secrets.HOMEBREW_GITHUB_API_TOKEN }}