# [RFC] Merge Bot
## Summary PRs authors must currently wait for changes to be manually merged by a committer clicking the "merge" button. A large amount of time can often elapse between CI going green, a PR being approved, and this merge button being pressed. This RFC proposes a safe, self-service mechanism to allow PR authors to merge their own PRs. This mechanism will also ensure better commit messages than GitHub's UI provides. ## Motivation The PR process currently looks something like this: 1. Develop and submit code 2. Request and wait for reviews 3. Iterate and address comments 4. Wait for CI 5. Ask a committer to merge the PR This RFC addresses steps 4 and 5. It is commonplace for TVM developers to have to ask a committer to merge a PR that has already been approved by someone else. Imagine if a simple PR was submitted and a reviewer accepts it minutes after it was posted. A committer will have to revisit this PR in the future, requiring another sync and more time out of their day, to mindlessly merge the PR (since it has already been accepted). It has also happened in the course of development that PRs that need to be monitored after merging (especially CI infrastructure changes) are merged at inopportune times for the author. Allowing users who are not committers to merge their own PRs solves this issue. TVM's commit messages are also poor. This is due to the fact that GitHub’s squash-and-merge strategy uses a commit message made by concatenating the first lines of all commits in a PR’s branch. These commits are often named irrelevant or nonsense things which do not belong in the history. Meanwhile, the first message in a PR thread often has a thoughtful and descriptive message which is usually more appropriate. This gets lost behind a level of indirection and is unavailable without a connection to GitHub. GitHub has no solution for this as can be seen in [this thread](https://github.community/t/how-to-change-the-default-squash-merge-commit-message/1155). See examples: - [https://github.com/apache/tvm/commit/dace8b72e3a8173704a689a7074df4c6f36bda4a](https://github.com/apache/tvm/commit/dace8b72e3a8173704a689a7074df4c6f36bda4a) - [https://github.com/apache/tvm/commit/73cf51b8246f1f0b5c0bff6fa206d154e053199b](https://github.com/apache/tvm/commit/73cf51b8246f1f0b5c0bff6fa206d154e053199b) ## Reference A bot implemented as a GitHub Actions workflow will listen for comments on PRs that match a pattern similar to: ``` @tvm-bot merge this ``` It will then check that the PR has been accepted by a valid reviewer / committer in its latest version. If so, it will rebase the PR on `main`, using the GitHub PR's body and title as the commit message and `push` to the `main` branch using a committer API key. If this fails (perhaps due to a push to `main` that happened in the meantime), it will re-attempt until successful. It will then leave a comment on the PR: ``` This PR has been merged with commit <commit short hash>. ``` or relevant information for debugging and who to contact if failed. The merge button on PRs could be effectively disabled by restricting the `main` branch to admin-only access. ## Prior Art PyTorch does this ## Disadvantages - This would be a non-standard flow, adding another piece of overhead to the TVM PR process that is outside of the typical process one would expect on GitHub. - Something to maintain - this would be another piece of automation for us to build. Given that we have dedicated resources for the CI though, this is manageable. ## Alternatives - Do nothing - continue with bad commit messages and slow PR merging. Maintaining the status quo is certainly an option, but given the pains felt by PR authors something probably needs to happen. - Make more people committers - This should happen anyway given the rising number of TVM contributors but there will always be people that aren't. In addition, the commit message issue persists even if people can merge their own PRs on GitHub. --- [Visit Topic](https://discuss.tvm.apache.org/t/allow-merging-via-pr-comments/12220/1) to respond. You are receiving this because you enabled mailing list mode. To unsubscribe from these emails, [click here](https://discuss.tvm.apache.org/email/unsubscribe/64440d86be8d618dd8dc598086a6e899083a4db5de604288c629f5ad7770cdea).
