Preventing Git-astrophe – Judicious use of the force flag

I’d like to tell a tale of a git-astrophe that I caused in the hope that others can learn from my mistakes. Git is awesome but also very feature-ful, which can lead to learning about some of those features at the worst times. In this episode, I abused my knowledge of git rebase, learned how the -f flag to git push works, and narrowly avoided learning about git reflog/fsck in any great detail.

Often times, you will need to rebase your feature branch against master (or production, in this case, it was a puppet controlrepo) before submitting a pull request for someone else to review. This isn’t just a chance to rewrite your commit history to be tidy, but to re-apply the changes in your branch against an updated main branch.

For instance, you created branch A from production on Monday morning, at the same time as your coworker created a branch B. Your coworker finished up her work on the branch quickly and submitted a PR that was merged on Monday afternoon. It took you until Tuesday morning to have your PR ready. At this time, it is generally adviseable to rebase against the updated production to ensure your branch behaves as desired after applying B‘s changes. Atlassian has a great tutorial on rebasing, if you are not familiar with the concept.

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