Clean Commits

• Atomic — one logical change per commit. Refactor and behavior change go in separate commits.
• Message — subject says WHAT in imperative ("Fix null pointer in user lookup"), body says WHY. "Fix bug" is useless.
• Specific — "Fix login failing when email has uppercase chars" tells the next person exactly what happened.
• Reorder/squash WIP and "fix typo" commits into the real changes (git rebase -i).
• Never mix an unrelated fix into a feature commit. A good history is a debugging tool: git bisect and git blame only work if commits are atomic and messages explain intent.