upload: Add superproject identifier as push option

When uploading, add the root superproject repo as a push option in the
format `-o custom-keyed-value=rootRepo:$HOST/$PROJECT`.

Bug: b/401147338
Change-Id: I00230256eb7ae307b03840bb4090c28dc8a0505e
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/472601
Reviewed-by: Josip Sokcevic <sokcevic@chromium.org>
Tested-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Gavin Mak <gavinmak@google.com>

git_superproject.py

@@ -28,6 +28,7 @@ import os
 import sys
 import time
 from typing import NamedTuple
+import urllib.parse
 
 from git_command import git_require
 from git_command import GitCommand
@@ -140,6 +141,23 @@ class Superproject:
             self._manifest_path if os.path.exists(self._manifest_path) else None
         )
 
+    @property
+    def repo_id(self):
+        """Returns the repo ID for the superproject.
+
+        For example, if the superproject points to:
+            https://android-review.googlesource.com/platform/superproject/
+        Then the repo_id would be:
+            android/platform/superproject
+        """
+        if review_url := self.remote.review:
+            parsed_url = urllib.parse.urlparse(review_url)
+            if netloc := parsed_url.netloc:
+                parts = netloc.split("-review", 1)
+                host = parts[0]
+                return f"{host}/{self.name}"
+        return None
+
     def _LogMessage(self, fmt, *inputs):
         """Logs message to stderr and _git_event_log."""
         message = f"{self._LogMessagePrefix()} {fmt.format(*inputs)}"