working with git

Working with GitFor the Android Developer

slideshare.net/thillerson

Tony Hillerson, AnDevCon Spring 2014

Presentation tackmobile.comPresentation tackmobile.com

About Me

• @thillerson, +thillerson

• Partner, Developer at Tack Mobile(tackmobile.com), @tackmobile

• Android, iOS, and Mobile Web

• Rails, Node, maybe Elixir (one day)

Presentation tackmobile.comPresentation tackmobile.com

What We’ll Cover Today

• The Git Database

• Configuration

• Working with Multiple Repositories

• ssh, submodules, subtrees

• Advanced Querying

• Git Flow for Delivering Releases

Presentation tackmobile.com

The Git DatabaseGet Acquainted


.git

• Each git repository has a database in the .git directory

• HEAD, FETCH_HEAD, ORIG_HEAD

• objects

• refs

• etc… hooks


Poking Around

• git show <commit>

• Shows blob contents, tree info, commit/ref logs

• git ls-tree

• git rev-list


ConfigurationGet Comfortable


gitconfig locations

Global /etc/gitconfig

User ~/.gitconfig

Local Project(not shared)

.git/config

git-scm.com/book/en/Customizing-Git-Git-Configuration

http://git-scm.com/book/en/Customizing-Git-Git-Configuration


Configure Colors

• git config color.diff auto

• [color] diff = autostatus = autobranch = autoui = true


Configure Aliases

• git config alias.co checkout

• [alias] co = checkoutcp = cherry-pickunstage = reset HEADlop = log -p


Terse Log

• [alias] lol = log --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset' --abbrev-commit --graph —decorate

• - Scott Chacon


You Have QuestionsGet Answers


When Was The First Commit?

• Assuming “master” is the conventional “master”:

• git log master --oneline | tail -n1


When Did This Branch Branch?

• git merge-base <branch> <parent>

• probably…

• git help merge-base


Do I Have The Latest Changes?

• git fetch - git must have the latest changes locally to tell you

• git log develop..origin/develop

• If no commits - yes, you have the latest

• Tools like SourceTree will often do automatic fetches


Do I Have Unpushed Changes?

• The opposite!

• git log origin/develop..develop


What’s Upstream?

• Upstream is the repository/branch from which changes come

• ➜ git status # On branch develop# Your branch is behind 'origin/develop' by 2 commits, and can be fast-forwarded.# (use "git pull" to update your local branch) #nothing to commit, working directory clean


Setting Upstream

• In .gitconfig:[branch]autosetupmerge = always

• git branch -u <remote> [branch]


Checking All Branches

• ➜ git branch -lvv * develop 24c4398 [origin/develop: behind 2] warning fixed. master 3cc12bb [origin/master: behind 3] Giving username an email keyboard for what seems to be the common use case.

• Add -a to include remotes


Is This Branch Merged?

• Which branches contain a given commit?

• git branch --contains <branch/commit>

• ➜ git branch --contains develop * develop

• ➜ git branch --contains master* developmaster


Where Did This Bug Come From?

• git bisect!

• Known Good Commit <|> Latest Buggy Commit

• build and run

• mark a commit good or bad

• git walks forward or backward

• repeat


Where Did My Commit Go?

• Have you lost a commit you know you made?

• git reflog!


Working With Multiple RepositoriesGet Integrated


Local Repos

• git clone <path> <new path>

• git push origin <branch>

• git pull origin <branch>

WAT


ssh

• git clone ssh://user@host/path/.git

• Push to origin

• Pull from origin

• Use when just starting out a private project?


Multiple Remotes

• git remote add <path>

• git push otherremote branch

• git pull otherremote branch

• Why? other upstream repo, maybe a fork


Submodules

• A git repository tracked as part of the tree of another repository

• Git (kind of) manages it

• cd in -> get another git repo

• Sort of a broken SVN external (the only thing I like better about SVN than git)


Submodules: What are they good for?

• Dependencies

• That are under frequent development

• That are not distributed as a jar or through maven


Submodules: Why do they suck?

• You have to be explicit about them; git won’t manage them for you

• Devs on your team need to be educated

• Have to jump through hoops to connect the repo back to its origin

• Hard to share local changes


Working with Submodules

• git submodule add <repo> <local name>

• .gitmodules

• Keeps submodule at a explicit commit

• ignore = dirty

• git submodule deinit, git rm


Submodules: Workflow

• If you need to move the submodule’s commit

• cd to submodule

• move to the new commit

• cd to parent

• git add and commit

• When you pull, add:git submodule update —install —recursive


Submodule Examples

• Utility Project


Submodule tips

• Avoid them.

• If you need to use them, make sure your team understands them.


Subtrees

• Add repo contents directly to tree

• http://blogs.atlassian.com/2013/05/alternatives-to-git-submodule-git-subtree/

http://blogs.atlassian.com/2013/05/alternatives-to-git-submodule-git-subtree/


Git FlowGetting Apps Shipped


Git Flow

• Conventions to follow

• Tools to help you follow conventions

• http://nvie.com/posts/a-successful-git-branching-model/

http://nvie.com/posts/a-successful-git-branching-model/


Git Flow Conventions: Master Branch

• The master branch is what is publicly available now

• You don’t commit directly to master


Git Flow Conventions: Develop Branch

• A branch called “develop” is what will become the next version

• Day to day work happens on develop

• “Integration branch”


Git Flow Conventions: Feature Branches

• Long running development go on feature branches: “feature/foo”

• Long running: “more than one commit”

• Can be pushed to the server and shared

• Branch from develop


Git Flow Conventions: Hotfixes

• OMG Problems in Production, create a hotfix: “hotfix/foo”

• Branch from master (not develop)


Git Flow Conventions: Releases

• When a release is almost ready on develop, create a release branch: “release/2.0.4”

• Branch from develop

• Develop continues on for the next release

• Small changes to release go on release branch


Branch Lifecycle

• Features

• Start from develop

• Finished and merged to develop

• Releases

• Start from develop

• Finished and merged to master and develop


Git Flow in Action: Features

feature/somefeature

master

develop


Git Flow in Action: Releases

release/v1.0

master

develop


The Take Home

• You know your way around .git

• You can customize and configure git

• You understand submodules and where they work (and don’t work)

• You know how git flow can help when releasing apps with a team

Thank you!Working with Git for the Android Developer • Tony Hillerson

• Questions?

• We’re Hiring! [email protected]

• Excellent Team

• Awesome Projects

• Great Office

mailto:[email protected]

working with git

Software

git fetch git

use git

git repository

git conguration

git status

git rm

bad git

git wont