feat: Add third-party repository support (#69)

* feat: add third-party (remote) repository support

* feat: add support for `checkout` step remote repository

* docs: add third-party repository usage

README.md

@@ -54,6 +54,7 @@ jobs:
     - name: pull-request
       uses: repo-sync/pull-request@v2
       with:
+        destination_repository: "owner/repository"        # If blank, default: checked out repository or triggered repository
         source_branch: ""                                 # If blank, default: triggered branch
         destination_branch: "master"                      # If blank, default: master
         pr_title: "Pulling ${{ github.ref }} into master" # Title of pull request
@@ -71,6 +72,33 @@ jobs:
         github_token: ${{ secrets.CUSTOM_GH_TOKEN }}      # If blank, default: secrets.GITHUB_TOKEN
 ```
 
+### Third-party repositories
+
+Since it's possible to `checkout` third-party repositories, you can either define `destination_repository` manually or let
+this action automatically pick up the checked out repository.
+
+```yaml
+jobs:
+  pull-request:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        repository: "octocat/hello-world"
+    - name: pull-request
+      uses: repo-sync/pull-request@v2
+      with:
+        destination_branch: "main"
+        github_token: ${{ secrets.GITHUB_TOKEN }}
+      # destination_repository: "octocat/hello-world" <- You can also do this but not necessary
+```
+
+**Priority will be set as follows:**
+
+1. `destination_repository` (Manually set)
+2. Checked out repository
+3. Repository that triggered the action (`GITHUB_REPOSITORY`)
+
 ### Outputs
 
 The following outputs are available: `pr_url`, `pr_number`, `has_changed_files ("true"|"false")`.

action.yml

@@ -5,6 +5,9 @@ branding:
   icon: 'git-pull-request'
   color: 'gray-dark'
 inputs:
+  destination_repository:
+    description: Repository (user/repo) to create the pull request in, falls back to checkout repository or triggered repository
+    required: false
   source_branch:
     description: Branch name to pull from, default is triggered branch
     required: false

entrypoint.sh

@@ -23,11 +23,33 @@ fi
 
 DESTINATION_BRANCH="${INPUT_DESTINATION_BRANCH:-"master"}"
 
+# Determine repository url
+if [[ -z "$INPUT_DESTINATION_REPOSITORY" ]]; then
+  # Try to query local repository's remote url if INPUT_DESTINATION_REPOSITORY is null
+  local_origin=$(git config --get remote.origin.url)
+
+  if [[ "$local_origin" == *.git ]]; then
+    origin_no_suffix="${local_origin%.*}"
+  else
+    origin_no_suffix="$local_origin"
+  fi
+
+  repo="$(basename "${origin_no_suffix}")"
+  owner="$(basename "${origin_no_suffix%/${repo}}")"
+
+  if [[ ! -z "$repo" ]]; then
+    CHECKOUT_REPOSITORY="$owner/$repo"
+  fi
+fi
+
+# Fallback to GITHUB_REPOSITORY if both INPUT_DESTINATION_REPOSITORY and CHECKOUT_REPOSITORY are unavailable
+DESTINATION_REPOSITORY="${INPUT_DESTINATION_REPOSITORY:-${CHECKOUT_REPOSITORY:-${GITHUB_REPOSITORY}}}"
+
 # Fix for the unsafe repo error: https://github.com/repo-sync/pull-request/issues/84
 git config --global --add safe.directory /github/workspace
 
 # Github actions no longer auto set the username and GITHUB_TOKEN
-git remote set-url origin "https://x-access-token:$GITHUB_TOKEN@${GITHUB_SERVER_URL#https://}/$GITHUB_REPOSITORY"
+git remote set-url origin "https://x-access-token:$GITHUB_TOKEN@${GITHUB_SERVER_URL#https://}/$DESTINATION_REPOSITORY"
 
 # Pull all branches references down locally so subsequent commands can see them
 git fetch origin '+refs/heads/*:refs/heads/*' --update-head-ok