How to use git without rage

Azul blanco

Xx de enero de 2010

Use git without rage

VCS should be a subject in informatics

Heared about VCS

We use VCS as if we were trained monkeys

Heared about VCS

Types of VCS

LVCS (Localized VCS)CVCS (Centralized VCS)DVCS (Distributed VCS)

LVCS

cp -r project projectB

rcs (mac os)

CVCS (Centralized VCS)

SVN

CVS

DVCS (Distributed VCS)

Git

Mercurial

Git Basics

First-time git setup

Three placesSystem: git config --system (/etc/gitconfig)

Global: git config --global (~/.gitconfig)

Local: git config (cwd)

git config [--system | --local] property valuegit config --global user.name 'wadus'

Git Basics

File status cycle

untrackedstagedmodifiedunmodified

git addeditgit addgit commitgit commit -a

Workflows

Scenario 1: Creating a repository from the beginnig and working with it

(with no rage)

Scenario 1: creating the repository

git init

(from directory project)

Pffffff... this was hard!!!!

Workflows -Scenario 1: edit some files

Edit and/or create some files for your project

this is what developing is about in last term, isn't it?

Workflows -Scenario 1: commiting changes

So, now you want to commit changes, but first... some advices for those who are used to working with CSCVs such as svn or cvs

100.times doputs I will think in local terms, 'cos I am not working with remotes (yet)

end

Workflows - Scenario 1: adding files to the staging area

git statusgit add add files to staging area (either new or modified files)

Wow!!! I could not have imagined it!!!!

Workflows Scenario 1: Removing files from the staging area

Damn it!!! I staged some files I didn't have to

git reset HEAD

Phewwww!!!!

Workflows Scenario 1: What am I about to commit?

Ok, I want to commit my changes, but which files I am about to commit?git statusgit diff (for unstaged files)git diff --cached (for staged files)

Workflows Scenario 1: Let's commit!!!

git commit it will commit all the files in staging areagit commit it will commit named filesgit commit -a it will commit all modified files skipping the staging area for those which are not staged

Workflows Scenario 1: deleting files

rm removes file manuallygit rm stages deletion

...or...

git rm will do both things

Workflows Scenario 1: undeleting files

git status will give you cluesif deletion is in the staging areagit reset HEAD

if deletion is not in the staging areagit checkout

Workflows Scenario 1: moving files

mv filename filename2git rm filenamegit add filename2

...or...

git mv filename filename2

Workfows- Scenario 1: undoing things

git commit --amend will modify last commit

git commitOMG, WTF, damn it!!! I forgot to add a file

git add damned_filegit commit --ammendcommit --amend FTW!!!

Workfows- Scenario 1: undoing things (ii)

Unstaging a staged filegit reset HEAD filename

Unmodify a modified and unstaged filegit checkout filename

Workflows

Scenario 2: working with remotes

Workfows- Scenario 2: adding a remote

So I want to work with another repo...

git remote add [shortname] [url]git remote add origin your_url

Now I finally understand what I've been doing with github all this time!!!

Workfows- Scenario 2: showing your remotes

If you want to know which repos you are working with:

git remotegit remote -v

Workfows- Scenario 2: fetching and pulling

To get data from your remotes

git fetch [remote-name]git pull [remote-name]

fetch or pull??? pull = fetch + merge

Workfows- Scenario 2: pushing

If you want to share your data:

git push [remote-name] [branch]

Workfows- Scenario 2: inspecting a remote

git remote show [remote-name]

Look at the Local ref configured for git push

Local refs configured for 'git push':master pushes to master (local out of date)test pushes to test (up to date)

Workfows- Scenario 2: removing and renaming remotes

git remote rename [original-name] [new-name]git remote rm [remote-name]

This changes take effect on your LOCAL repo(remember: local, local, local)

Workflows

Scenario 3: tagging

Workfows- Scenario 3: listing tags

git tag

Workfows- Scenario 3: tag types

2 types of tags: lightweight and annotated

Lightweight: It is like a branch that doesn't change, a pointer to a specific commitAnnotated: These are stored as full objects. Checksumed and metadata are included

Workfows- Scenario 3: Creating and showing tags

Annotated:git tag -a [tag]

Lightweight:git tag [tag]

git show [tag]

Workfows- Scenario 3: Creating tags later

git tag -a

Workfows- Scenario 3: Sharing tags

When pushing, you do not share tags

git push origin [tagname]

Hey! This is like sharing branches...

git push origin --tags shares all the tags

Branching: the beginning of magic

Please, keep on thinking in local... or I will send @pacoguzman to kill you!!!


Let's do some review...

git add README test.rb LICENSEgit commit -m 'initial commit of my project'

How is this commit stored?


taken from http://progit.org/


Let's assume we keep on doing some commits




I thought we were going to talk about branches, you son of the bit!!!


I thought we were going to talk about branches, you son of the bit!!!

A very bad geek joke


Branch: A movable pointer to one of these commits.

Do you smell it??? Yeah! And it seems that it's going to taste even better!




So... let's imagine we want to make a new branch:

git branch testing




Hey! But somehow I have to know wich branch I am at, aren't I???




git checkout testing




Very pretty... but... how the hell is this supposed to be useful???


touch newfile.txtgit commit -a -m 'new file'




git checkout master




touch another_file.txtgit commit -a -m 'another new file in master branch'



Workflows

Scenario 4: working with branches

Scenario 4: Context

You are working on a new story, comfortably and peacefully when suddenly you receive a call

OMG!and you are told that it is urgent - but surely not important - to fix some bug in the application(e.g: to change some text which only appears in that last screen of your app)

Scenario 4: steps resume

Create a branch for the new story you are going to work on

Do some work on that branch

Swear after you receive that f*ck*ng damned call

Commit or stash all the changes that you haven't saved yet if you want to -

Checkout your production (usually master) branch

Create a branch to add the hotfix

Fix that so f*ck*ng urgent issue

Merge this branch and push it to production

Switch back to your original story and continue working on it

Scenario 4: the process

git checkout master -b issue_1

C1C3C2

master

* issue_1


make some changes and commit them

C1C3C2

master

* issue_1

C4


Create a new branch from master for that hotfixgit checkout master -b hotfix

C1C3C2

master

issue_1

C4

* hotfix


Fix the problem and commit changes

C1C3C2

master

issue_1

C4

* hotfix

C5

Scenario 4: fast forward merge

Merge hotfix into mastergit checkout mastergit merge hotfix

C1C3C2

* masterissue_1

C4

hotfix

C5

Scenario 4: fast forward merge

What kind of merge is this!!!You have done nothing but moving forward master pointer

C1C3C2

* masterissue_1

C4

hotfix

C5


End issue_1 and commit changes

C1C3C2

* masterissue_1

C4

hotfix

C5

C6

Scenario 4: three way merge

Merge changesgit checkout mastergit merge issue_1

C3

issue_1

C4

hotfix

C5

C6

* master

Scenario 4: three way merge

C3

* masterissue_1

C4

hotfix

C5

C6

C7

Merge changesgit checkout mastergit merge issue_1

Scenario 4: merge conflicts

If there are merge conflicts you have to solve them manually.Once you have resolved them, you can set these files as merged withgit add git commit

Scenario 4: branch management

git branch lists branchesgit branch -v lists branches with their last commitgit branch --merged lists merged branchesgit branch --no-merged lists unmerged branchesgit branch -d deletes merged branch (-D for unmerged branches)

Branching workflows

Branching workflows: long running branches


Branching workflows: topic branches


Branching workflows: topic branches

Merge iss91v2 and dumbidea


Remote branches

References to the state of branches on your remote repos

They are local branches which you can not move. They are moved automatically whenever you do any network communication

Pushing branches

git push [:server_branch_name]

git push origin my_local_branch:server_branch

Deleting remote branches

git push origin :branch_to_be_deleted

It's like

git push origin (nothing):branch_to_be_deleted

Tracking branches

Checking out a remote branch, will create a tracking branch. With tracking branches you can callgit pushgit pull

without remote or branches namesWhen you clone a repo, a local branch master is created, which tracks origin/master

Rebasing

Basic rebasing vs merge

This is what we already knowgit merge experiment



And this is rebasinggit rebase master experiment or...git checkout experimentgit rebase master




It gets the diffs introduced by each commit of the branch you're on.It saves those diffs to temporary filesIt resets the current branch to the common ancestor with the branch you are rebasing ontoIt applies these changes and creates a new commit


Now, you can do a fast forward merge


Rebasing onto other branches



git rebase --onto master server client



git checkout mastergit merge client



git rebase master server


Rebasing or not rebasing?

Be very careful when rebasing commits published in a public repository...

you could be killed by other developers




Fetch changes in remote repo



Someone rebased changes (C4 C6)



C4 and C4' introduce the same changes


DISTRIBUTED WORKFLOWS

Centralized workflow (small teams)


Integration manager workflow (github)


Dictator Lieutenant Workflow (linux kernel)


Tricks & Tips

Stashing

If you're working on some feature and suddenly you are forced to work on a hotfix, what do you do with changes in code you don't want to commit?

The answer is Stash

Stashing (i)

git stash [save 'message'] saves changesNote: if you have untracked files, these won't be stashed

git stash list

Stashing (ii)

git stash apply [stash_id] applies stashgit stash drop [stash_id] deletes stashgit stash pop [stash_id] applies + deletesgit stash show [stash_id] -p|git apply -R unapplies (careful with new files)git stash [stash_id] branch branchname applies into new branch

Rewriting history

Changing the last commit git commit --ammend

Changing historygit rebase -i \ e.g git rebase -i HEAD~3e.g git rebase my-tag~1

Rewriting history: actions

pick: use commit normallyreword: use commit but edit commit messageedit: use commit but stop for amendingsquash: use commit but meld into previous onefixup: like squash, but discard this commit's log message

Cherry picking

If you want to get one commit out of a branch

git cherry-pick (from the branch which you want the commit into)Be careful because it ends with two different commits which introuduces the same set of changes

Getting file's content of a specific revision

git show :

with this you get the content of that file

Debugging with git: file anotation

git blame [-L line1, line2]

you can see when each line of the method was edited and by whom

Debugging with git: binary search

git bisect startgit bisect bad [commit_id]git bisect good [commit_id]git bisect reset

References

http://progit.orghttp://gitready.comgit man pages

!gracias!

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How to use git without rage

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