fix: configure upstream remote for cross-repo PR rebasing (#2505)

.claude/commands/dyad/pr-rebase.md

@@ -4,14 +4,18 @@ Rebase the current branch on the latest upstream changes, resolve conflicts, and
 
 ## Instructions
 
-1. **Determine the base branch:**
+1. **Determine the git remote setup:**
 
    ```
    git remote -v
    git branch -vv
    ```
 
-   Identify which remote and branch the current branch is tracking or should rebase onto (typically `main` or `master` from `upstream` or `origin`).
+   In GitHub Actions for cross-repo PRs:
+   - `origin` points to the **head repo** (fork) - this is where you push
+   - `upstream` points to the **base repo** - this is what you rebase onto
+
+   For same-repo PRs, `origin` points to the main repo and there may be no `upstream`.
 
 2. **Fetch the latest changes:**
 
@@ -21,12 +25,13 @@ Rebase the current branch on the latest upstream changes, resolve conflicts, and
 
 3. **Rebase onto the base branch:**
 
+   Use `upstream/main` if the `upstream` remote exists (cross-repo PR), otherwise use `origin/main`:
+
    ```
-   git rebase <remote>/<base-branch>
+   # Check if upstream remote exists
+   git remote get-url upstream 2>/dev/null && git rebase upstream/main || git rebase origin/main
    ```
 
-   For example: `git rebase upstream/main`
-
 4. **If there are merge conflicts:**
    - Identify the conflicting files from the rebase output
    - Read each conflicting file and understand both versions of the changes

.github/workflows/claude-rebase.yml

@@ -36,6 +36,20 @@ jobs:
           ref: ${{ github.event.pull_request.head.ref }}
           fetch-depth: 0
 
+      - name: Configure git remotes for cross-repo PR
+        if: steps.check-author.outputs.should_continue == 'true'
+        run: |
+          # Add upstream remote pointing to the base repo for rebasing
+          git remote add upstream https://github.com/${{ github.repository }}.git
+          git fetch upstream main
+
+          echo "Git remotes configured:"
+          echo "  origin -> ${{ github.event.pull_request.head.repo.full_name }} (head repo / fork)"
+          echo "  upstream -> ${{ github.repository }} (base repo)"
+          git remote -v
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
       - name: Remove cc:rebase label and add cc:rebasing
         if: steps.check-author.outputs.should_continue == 'true'
         run: |

AGENTS.md

@@ -217,6 +217,15 @@ Add `#skip-bugbot` to the PR description for trivial PRs that won't affect end-u
 
 ## Learnings
 
+### Cross-repo PR workflows (forks)
+
+When running GitHub Actions with `pull_request_target` on cross-repo PRs (from forks):
+
+- The checkout action sets `origin` to the **fork** (head repo), not the base repo
+- To rebase onto the base repo's main, you must add an `upstream` remote: `git remote add upstream https://github.com/<base-repo>.git`
+- Remote setup for cross-repo PRs: `origin` → fork (push here), `upstream` → base repo (rebase from here)
+- The `GITHUB_TOKEN` can push to the fork if the PR author enabled "Allow edits from maintainers"
+
 ### TooltipTrigger render prop (Base UI)
 
 - `TooltipTrigger` from `@base-ui/react/tooltip` (wrapped in `src/components/ui/tooltip.tsx`) renders a `<button>` by default. Wrapping another button-like element (`<button>`, `<Button>`, `<DropdownMenuTrigger>`, `<PopoverTrigger>`, `<MiniSelectTrigger>`, `<ToggleGroupItem>`) inside it creates invalid nested `<button>` HTML. Use the `render` prop instead: