build: Add GitHub scripts for rebasing PRs (#18359)

PR Close #18359

scripts/github/rebase-pr

@@ -0,0 +1,45 @@
+#!/bin/sh
+
+set -u -e -o pipefail
+
+BASEDIR=$(dirname "$0")
+
+if [ $# -eq 0 ]; then
+    echo "Rebase github PR onto a branch"
+    echo
+    echo "$0 branch_to_rebase_on PR_NUMBER"
+    echo
+    exit 0
+fi
+
+REBASE_ON="$1"
+PR_NO="$2"
+
+
+HEAD_LABEL=`curl -s https://api.github.com/repos/angular/angular/pulls/$PR_NO | node $BASEDIR/utils/json_extract.js head.label`
+echo $HEAD_LABEL
+IFS=':' read -r -a array <<< "$HEAD_LABEL"
+USER="${array[0]}"
+USER_GIT_URL="git@github.com:$USER/angular.git"
+BRANCH="${array[1]}"
+OLD_BRANCH=`git branch | grep \* | cut -d ' ' -f2`
+
+echo =====================================================
+echo Rebasing $USER_GIT_URL branch $BRANCH onto $REBASE_ON
+echo =====================================================
+
+git fetch $USER_GIT_URL $BRANCH
+git co FETCH_HEAD
+PUSH_CMD="git push $USER_GIT_URL HEAD:$BRANCH -f";
+RESTORE_CMD="git co $OLD_BRANCH"
+git rebase upstream/master
+if [ $? -eq 0 ]; then
+    $PUSH_CMD
+    $RESTORE_CMD
+else
+    echo ===========================
+    echo Git rebase failed. RECOVER WITH:
+    echo "       $PUSH_CMD"
+    echo "       $RESTORE_CMD"
+    echo ===========================
+fi