[workflow/rebase-on-upstream] Avoid moving nightly-specific commits

* replace rebase-on-upstream workflow action from ytdl-patched with local
workflow
* rebase upstream onto nightly, so appending new upstream commits
* local workflow also avoids deprecated 3rd-party actions.

.github/workflows/rebase-on-upstream.yml

@@ -22,7 +22,7 @@ jobs:
         echo "HEAD_NOW=$(git rev-parse HEAD)" >> "$GITHUB_ENV"
     - name: Rebase
       # fetches upstream as git remote `upstream`
-      uses: ytdl-org/ytdl-patched-rebase-upstream-action@master
+      uses: ./.github/workflows/rebaser.yml
       with:
         token: ${{ secrets.GH_PAT }}
         upstream: ytdl-org/youtube-dl

.github/workflows/rebaser.yml

@@ -0,0 +1,70 @@
+# Use git rebase to append new upstream commits
+# inverted logic from imba-tjd/rebase-on-upstream
+name: Reverse Rebase from Upstream
+on:
+  workflow_call:
+    inputs:
+      upstream:
+        type: string
+        description: <user>/<repo> or the full HTTP URL
+        required: false
+      branch:
+        type: string
+        description: The upstream branch that is rebased from
+        required: false
+        default:  master
+      push:
+        type: boolean
+        description: Do the force push in this action
+        required: false
+        default:  true
+      token:
+        type: string
+        description: GitHub Access Token
+        required: true
+        default:  ${{ github.token }}
+
+permissions:
+  contents: write
+
+jobs:
+  rebaser:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Main
+      shell: bash
+      run: |
+        set -ex
+        # Starting with current git branch (TARGET), get the UPSTREAM branch
+        # as a temporary branch; rebase TARGET onto it; if that differs from TARGET,
+        # make it the TARGET and push the result, if the remote hasn't changed.
+        # Effect: commits specific to the TARGET repo stay in place; new UPSTREAM
+        # commits are appended
+        TARGET_SHA=$(git rev-parse HEAD)
+        TARGET=$(git name-rev --name-only "$TARGET_SHA")
+        if [ -z "$TARGET" ]; then echo "Can't find current branch" >&2; exit 1; fi
+        UPSTREAM=${{ inputs.upstream }}
+        if [ -z "$UPSTREAM" ]; then
+          echo "${{ inputs.token }}" | gh auth login --with-token
+          UPSTREAM=$(gh api repos/:owner/:repo --jq .parent.full_name
+          if [ -z "$UPSTREAM" ]; then echo "Can't find upstream" >&2 && exit 1; fi
+        fi
+        if ! echo "$UPSTREAM" | grep -E '^(http|git@)'; then
+          UPSTREAM=https://github.com/$UPSTREAM.git
+        fi
+        git remote add -f -t "${{ inputs.branch }}" --tags upstream "$UPSTREAM"
+        REBASE=${TARGET}-rebase
+        trap '{ git checkout "$TARGET"; git branch -D "$REBASE"; }' EXIT
+        git checkout -B  "$REBASE" --no-track "upstream/${{ inputs.branch }}" 
+        git config --local user.email "rebaser+github-actions[bot]@users.noreply.github.com"
+        git config --local user.name  "GitHub Actions"
+        # rebase new UPSTREAM commits onto TARGET
+        UPSTREAM_SHA=$(git rev-parse HEAD)
+        git rebase "refs/heads/${TARGET}"
+        if [ -n "$(git log --max-count 1 --oneline "HEAD...${TARGET}")"  ]; then
+          git branch -M "$REBASE" "$TARGET"
+          if [ "${{ inputs.push }}" = true ]; then
+            # rebase changed TARGET: push if remote TARGET unchanged
+            git push origin --force-with-lease="${TARGET}"
+          fi
+        fi