Git Branching for Success and Profit

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Git Branching For Success and Profit Lorna Mitchell, Day Camp For Developers

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Git Branching

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A Branch is a Label Take a look in .git/refs/heads/ • A branch is a pointer to a commit. • You commit on a branch, the commit is created and the pointer updated.

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Commits Aren't "On" Branches

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Commits Aren't "On" Branches

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11% of branches never get merged

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86% of statistics are made up on the spot

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Git Branch We are committing along:

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Git Branch We create a branch and keep committing: git branch feature and git checkout feature git checkout -b feature

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Git Branch Stuff happens on master meanwhile:

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Branching is easy. Merging is ?

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Branching is easy. Merging is easy when you know how.

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Git Merge

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Git Merge The plan: • Check out the branch that changes should arrive into. • Merge. git checkout master git merge feature

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Git Merge

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Git Undo

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Git Undo How to undo a merge: • Set the branch pointer back to where it was before the merge git reset --hard 7e386 (your branch is still intact)

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Git Undo

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Undo an Old Merge Use git revert but specify which way you want to go at the fork git revert -m 1 d1151

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Merge Conflicts Merge conflicts occur when git needs some help.

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DON'T PANIC

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Merge Conflicts: Your Options • git merge --abort • Edit the files until things are correct • Use git checkout --[ours|theirs] to get the right version in place Fix the conflict, then add and commit the file(s). Your merge will complete

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Merge Types

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Fast-Forward Merge No changes on master since we branched

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Fast-Forward Merge git merge feature

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Force Recursive Merge Start from the same place:

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Force Recursive Merge Then merge without fast-forward: git merge --no-ff feature

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Git Rebase

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Git Rebase Rebase to move a branch start point

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Git Rebase git rebase master We can now fast-forward merge

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Rebase Conflicts Rebase applies each of your commits in turn. This can result in a conflict at any point. Handle exactly as you would for merge conflicts. Then type git rebase --continue. git rebase --abort is always an option.

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Interactive Rebase Rewrite the last N commits. Your options: • remove a commit completely • re-order commits • combine commits and/or re-word their commit messages

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Branching Strategies

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Branching Strategies A branching strategy is basically a git process document. It covers: • when to branch • where to branch from • what to call your branch • where to merge to

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Git Flow Comprehensive branching strategy, supported by scripts. • Article: http://lrnja.net/1ebawKU • Scripts: https://github.com/nvie/gitflow

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Git Flow

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Git Flow

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Git Flow

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Git Flow

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Git Flow

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Other Branching Strategies • GitHub Flow: http://lrnja.net/1Gr29Jn • Atlassian blog: http://lrnja.net/1BSFQcQ • Docs from GitLab: http://lrnja.net/1AiPxQJ Some common elements can be spotted throughout

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Branching Strategy Ingredients List

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Topic Branches Pattern Starting something new? Use a branch.

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Topic Branches Pattern Merge from master into feature before merging

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Topic Branches Pattern Rebase branch onto master before merging

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Master vs Develop This one is a matter of taste!

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Hotfix Pattern Branch off, commit once, merge with --no-ff • makes it very clear what happened • easily merge the branch back upstream if needed • makes it possible to cleanly undo without losing anything

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Hotfix Pattern

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Environment Branches Maintain one branch per platform • branch always reflects current state of platform • plays well with automated deployment

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Environment Branches

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Tagging for Releases Git has two types of tags: • simple tags are just a label, like a branch that doesn't advance • annotated tags are an object, they can contain messages git tag -a v2.11 -m "v2.11 with caching" Then push the tag

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Git Branches

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Feedback (and Resources) • How was it? https://m.joind.in/talk/50bd3 • Links bundle: http://lrnja.net/135jCIy • My git book: http://gitworkbook.com/ See Also: • Matthew's Scripts: http://lrnja.net/1AiQrgh