ci: use pull_request_target to enable support for forked repos

.github/workflows/pr-open.yaml

@@ -1,9 +1,7 @@
 name: PR Opened
-
 on:
-  pull_request:
+  pull_request_target:
     types: [opened, reopened]
-
 jobs:
   open-data-pr:
     name: Open deadlock-data PR
@@ -15,62 +13,71 @@ jobs:
         uses: actions/checkout@v4
         with:
           path: deadbot
+          # For forks, check out the base repo code, not the fork's code
+          ref: ${{ github.event.pull_request.base.ref }}
 
       - name: Checkout deadlock-data repo
         uses: actions/checkout@v4
         with:
           repository: deadlock-wiki/deadlock-data
           path: deadlock-data
-          token:  ${{ secrets.GH_TOKEN }}          
+          token: ${{ secrets.GH_TOKEN }}
 
       - name: Configure Git
-        working-directory: deadlock-data 
+        working-directory: deadlock-data
         run: |
           git config --global user.email "deadbot1101@gmail.com"
           git config --global user.name "Deadbot0"
           git config pull.rebase true
 
+      - name: Set branch name
+        id: branch
+        run: |
+          IS_FORK=${{ github.event.pull_request.head.repo.full_name != github.repository }}
+          if [ "$IS_FORK" = "true" ]; then
+            # Prefix with actor to avoid collisions across forks
+            echo "name=fork-${{ github.actor }}-${{ github.head_ref }}" >> $GITHUB_OUTPUT
+          else
+            echo "name=${{ github.head_ref }}" >> $GITHUB_OUTPUT
+          fi
+
       - name: Create working branch on deadlock-data repo
-        working-directory: deadlock-data 
+        working-directory: deadlock-data
         run: |
           git fetch origin
-
-          if git ls-remote --exit-code --heads origin ${{ github.head_ref }}; then
+          BRANCH="${{ steps.branch.outputs.name }}"
+
+          if git ls-remote --exit-code --heads origin "$BRANCH"; then
             # branch exists, update local branch
-            git switch ${{ github.head_ref }}
-            git pull origin ${{ github.head_ref }} -X ours
+            git switch "$BRANCH"
+            git pull origin "$BRANCH" -X ours
           else
             # create new local branch
-            git checkout -b ${{ github.head_ref }} origin/${{ github.event.pull_request.base.ref }}
+            git checkout -b "$BRANCH" origin/${{ github.event.pull_request.base.ref }}
           fi
-
           git commit --allow-empty -m "chore: empty commit to enable PR creation"
-          git push --force-with-lease --set-upstream origin ${{ github.head_ref }}
-
-      # Creates a PR to enable viewing the outcome of the deadbot changes
+          git push --force-with-lease --set-upstream origin "$BRANCH"
+
       - name: Create PR on deadlock-data repo
         id: create_data_pr
-        working-directory: deadlock-data 
+        working-directory: deadlock-data
         run: |
           gh auth login --with-token <<< ${{ secrets.GH_TOKEN }}
+          BRANCH="${{ steps.branch.outputs.name }}"
           pr_url=$(
             gh pr create \
-              --head ${{ github.head_ref }} \
+              --head "$BRANCH" \
               --base ${{ github.base_ref }} \
-              --title ${{ github.head_ref }} \
+              --title "$BRANCH" \
               --body "_PR Auto-generated by [deadbot PR](https://github.com/deadlock-wiki/deadbot/pull/${{ github.event.number }})_"
           )
           echo "pr_url=$pr_url" >> $GITHUB_OUTPUT
 
-      # for a newly made PR, add the reference into the PR body 
       - name: Reference deadlock-data PR in deadbot PR body
         if: steps.create_data_pr.outputs.pr_url != ''
-        working-directory: deadbot 
+        working-directory: deadbot
         run: |
           current_body=$(gh pr view ${{ github.event.number }} --json body -q ".body")
-
           new_body="$current_body
-
           _Parsed data in [deadlock-data PR](${{ steps.create_data_pr.outputs.pr_url }}) - Reopen deadbot PR or run deploy workflow for this branch [here](https://github.com/deadlock-wiki/deadbot/actions/workflows/deploy.yaml) to reparse the data_"
-
-          gh pr edit ${{ github.event.number }} --body "$new_body"  
+          gh pr edit ${{ github.event.number }} --body "$new_body"