Git on the front line

In the years spent on the front line managing open source projects and applications developed by distributed teams, I've managed to gather quite a few Git stories from the trenches. In this practically oriented talk, I will share some patterns and practices I have collected while on the front.

Presented at:
- Codemotion 2017, Milan
- WPC 2017, Milan

Transcript

1. 1
   Git on the front line
   Nicola Iarocci
   

   View Slide

2. 2
   Who Am I
   Nicola Iarocci, a weirdo
   Python by Night
   I am the author and
   maintainer of a few
   Python open source
   projects: python-eve.org,
   python-cerberus.organd
   more.
   Microsoft MVP
   MongoDB Master
   I also happen to be a
   Microsoft MVP for Visual
   Studio and Development
   Technologies and a
   MongoDB Master.
   Communities
   I run DevRomagna, a
   developers community, and
   CoderDojo Ravenna, a
   coding club for kids.
   http:/
   /devromagna.org
   C# by Day
   I am the author of Sofware
   Gestionali Amica, a line of
   accounting and invoicing
   applications for Italian small
   businesses. Check it out at
   http:/
   /gestionaleamica.com
   

   View Slide

3. 3
   one size does not fit all
   git workflows
   

   View Slide

4. 4
   the main branch where the source code of HEAD
   always reflects a production-ready state
   origin/master
   main branch where HEAD always holds the latest
   delivered development changes, ready for next release
   origin/develop
   feature, release and hotfix branches. these always have
   a limited life time, since they will be removed eventually
   supporting branches
   an elegant mental model well suited for packaged
   software. Not ideal for frequent release cycles such as
   those we have in modern web development
   summary
   Git Flow
   a successful git branching model
   http:/
   /nvie.com/posts/a-successful-git-branching-model/
   

   View Slide

5. 5
   the main branch where the source code of HEAD
   always reflects a production-ready state
   origin/master
   to work on something new, create a descriptively named
   branch off of master branch
   feature branch
   when you need feedback or help, or you think the
   branch is ready for merging, open a pull request
   pull request & review
   a lightweight, branch-based workflow that supports
   teams and projects where deployments are made
   regularly
   summary
   GitHub Flow
   widely adopted by the open source community
   http:/
   /scottchacon.com/2011/08/31/github-flow.html
   

   View Slide

6. 6
   Streamline your git experience
   aliases
   

   View Slide

7. 7
   git status, succinctly
   $ git st
   ## work
   M README.md
   $ git config —-global alias.st ‘status -sb’
   

   View Slide

8. 8
   show last commit
   $ git last
   commit c828339f02f832818f868bbfe457e64bfcc3e64a
   Author: Nicola Iarocci
   Date: Thu Oct 19 10:28:42 2017 +0200
   first commit
   $ git config —-global alias.last ‘log -1 HEAD’
   

   View Slide

9. 9
   quick branch checkout
   $ git co mybranch
   switched to branch ‘mybranch’
   $ git config —-global alias.co ‘checkout’
   Hint: git co - works like cd - but between branches (git checkout - works, too)
   

   View Slide

10. 10
    checkout to a new branch
    $ git cob newbranch
    switched to a new branch ‘mybranch’
    $ git config —-global alias.cob ‘checkout -b’
    branch is created on the fly
    

    View Slide

11. 11
    amend last commit
    $ git amend
    
    $ git config —-global alias.amend ‘commit —-amend’
    

    View Slide

12. 12
    add staged changes to last commit
    $ git add .
    $ git fixup
    $ git config —-global alias.fixup ‘commit —-amend —-noedit’
    skip editing the commit message
    

    View Slide

13. 13
    unstage changes
    $ git st
    ## work
    M README.md
    $ git unstage README.md
    Unstaged changes after reset:
    M README.md
    $ git config —-global alias.unstage ‘reset HEAD’
    pass no filename to unstage all, or use wildcard
    

    View Slide

14. 14
    show staged changes
    $ git diffc
    diff —git a/README.md b/README.md
    index 2fd9bc4..889c3dc 100644
    --- a/README.md
    +++ b/README.md
    @@ -1 +1,2 @@
    TITLE
    +test
    $ git config —-global alias.diffc ‘diff —-cached’
    

    View Slide

15. 15
    undo last commit and keep changes
    $ git r1
    Unstaged changes after reset:
    M README.md
    $ git config —-global alias.r1 ‘reset HEAD^’
    changes are left unstaged
    

    View Slide

16. 16
    undo last commit, discard changes
    $ git rh1
    HEAD is now at c828339 first commit
    $ git config —-global alias.rh1 ‘reset -—hard HEAD^’
    use with caution
    

    View Slide

17. 17
    add all changes including untracked,
    and commit with message
    $ git cm “my commit message”
    [mybranch ea88184] my commit message
    1 file changed, 1 insertion(+), 1 deletion(-)
    !git add -A && git commit -m
    

    View Slide

18. 18
    add all changes excluding untracked,
    then commit as WIP
    $ git wip
    [mybranch ea88184] WIP
    1 file changed, 1 insertion(+), 1 deletion(-)
    !git add -u && git commit -m WIP
    

    View Slide

19. 19
    add all changes including untracked,
    then commit as SAVEPOINT
    $ git save
    [mybranch ea88184] SAVEPOINT
    1 file changed, 1 insertion(+), 1 deletion(-)
    !git add -A && git commit -m SAVEPOINT
    

    View Slide

20. 20
    resume work after WIP or SAVEPOINT
    $ git undo
    Unstaged files after reset:
    M README.md
    $ git config —-global alias.undo ‘reset HEAD^ —-mixed’
    functionally identical to ‘r1’ but makes more sense semantically
    

    View Slide

21. 21
    add changes to commit, then wipe that commit
    $ git wipe
    HEAD is now at 8da9860 my commit message
    $ git reflog
    8da9860 HEAD@{0}: reset: moving to HEAD~1
    4998619 HEAD@{1}: commit: WIPE SAVEPOINT
    $ git reset —hard 4998619
    HEAD is now at 4998619 WIPE SAVEPOINT
    !git add -A && git commit -qm 'WIPE SAVEPOINT' && git reset HEAD~1 --hard
    now working dir is clean, but I can still go back if need arises (via reflog)
    

    View Slide

22. 22
    hierarchical, git-powered grep
    $ git g “event hooks”
    CHANGES
    1077:- [new] pre_ and ``pre__`` event hooks are
    now
    docs/features.rst
    1216:Database event hooks
    1219:Database event hooks work like request event hooks
    $ git config —-global alias.g ‘grep --break --heading --line-number’
    faster than standard grep
    

    View Slide

23. 23
    show a tree with all branches
    $ git tree
    * bbde45f (HEAD -> expand_cerberus_registries) WIP
    * 3a25ea7 (origin/master, master) Merge branch ‘use_ordereddict_from_backport_collections_#1070’
    |\
    | * 9fb1a66 Changelog for #1070
    | * fa8da19 use OrderedDict from backport_collections
    |/
    * cee2f7e Merge branch 'support_for_decimal_type_#1048'
    |\
    | * 46af495 Minor changelog fixes for #1048
    | * 3bf1930 Support Decimal type MongoDB
    |/
    !git log --graph --decorate --all --oneline
    which brings us to the next topic…
    

    View Slide

24. 24
    push/unpush current branch to remote
    $ git publish
    $ git unpublish
    In .gitconfig:
    branch-name = "!git rev-parse --abbrev-ref HEAD"
    publish = "!git push -u origin $(git branch-name)"
    unpublish = "!git push origin :$(git branch-name)"
    and set it to track upstream branch
    

    View Slide

25. 25
    delete branches already merged to master
    $ git delete-merged-branches
    Deleted branch add_new_user_gravatar_links
    Deleted branch assign_unique_key_to_uploads
    Deleted branch remember_the_last_activity_per_user
    Deleted branch update_kaminari_to_thread_safe_version
    “!git branch —-merged master | grep -v '\\*' | xargs -n 1 git branch -d"
    

    View Slide

26. 26
    shortcut to .config file
    $ git ec
    
    $ git config —-global alias.ec ‘config —global —e’
    

    View Slide

27. 27
    get my dotfiles
    https:/
    /github.com/nicolaiarocci/dotfiles
    

    View Slide

28. 28
    keep your history clean and consistent
    rebase
    Demo
    a documentation project
    

    View Slide

29. 29
    reuse recorded resolutions to solve hunk conflicts
    rerere
    $ git config —-global rerere.enabled true
    https:/
    /git-scm.com/blog/2010/03/08/rerere.html
    

    View Slide

30. 30
    shows all non-common commits in two branches (@antirez)
    rx script
    

    View Slide

31. 31
    Aliases
    Streamline your workflow.
    Don’t Repeat Yourself.
    Consider sharing with team.
    Rebase
    Keep project history clean,
    compact and consistent. Not
    as hard as you thought.
    Keep Learning
    Study more advanced git
    features. Consider building
    your own scripts.
    Pick a Workflow
    Don’t be afraid to customize
    it just to suit your use case,
    project, and team.
    You Are a Craftsman
    sharpen your tools
    

    View Slide

32. 32
    nicolaiarocci.com nicola@nicolaiarocci.com
    @nicolaiarocci
    Thank You!
    Send feedback or get in touch at
    

    View Slide