2.3Branches, Integration, and Undo

Branches are the core of parallel development: keep main stable while you try changes safely on a feature branch.

■ Create and switch • git branch = create/list branches. • git switch <branch> (formerly git checkout) = switch branches. git switch -c <name> creates and switches at once.

■ Integration: merge vs rebase (see the diagram) There are two ways to bring in a branch’s changes. • merge = integrate while preserving both histories, with a "merge commit" marking the join—history shows what happened. • rebase = replay your commits onto the target branch’s tip to linearize history—cleaner history, but rebasing already-shared commits causes divergence, so be careful. Editing the same spot differently causes a merge conflict; resolve the spot manually, then complete the integration.

■ Undo, shelve, mark • git revert <commit> = add an "undo" commit—safe to undo even when shared. • git reset = roll back history or staging (--hard discards changes—use with care). • git stash = temporarily shelve uncommitted changes to restore later. • git cherry-pick <commit> = apply just a specific commit onto the current branch. • git tag = mark a point such as a release. Note: avoid force-pushing shared branches—it overwrites history and can lose others’ work.