How to fix 'Out-of-Date with the Base Branch'?

[azarboon]

I’ve been experiencing difficulty making pull requests (PRs) in the AWS CDK, and the issue isn’t addressed in the contributing guidelines. I follow the steps outlined: I fork the repository, ensure it’s synced with the latest changes, create a feature branch based on the most recent main branch in my account, and then make the PR (confirming my main branch is up-to-date throughout the process). However, apparently after any new commit to AWS CDK, my PR displays the message "This branch is out-of-date with the base branch." I’ve tried both committing and rebasing to update the branch, but the issue persists.

I’ve followed this process on both Windows and the GitHub UI (making sure my fork has the latest changes before creating the PR), yet the issue continues. This is proving to be frustrating. Could you help clarify what might be causing this issue? I’ve never encountered such a problem in any other open source repositories I’ve contributed to.

Here are two examples of the issue:

1. My latest PR, which is experiencing the issue: PR #32889
2. The previous PR I created, which I updated using both methods but still encountered the issue: PR #32850