Introduction to VCS 

@AlexeyBuzdin Developer / Trainer at 

How to work in a team? 

Solutions? • FTP server • Dropbox • USB drive 

What do we need? • “Checkout-Change-Commit” approach • Disable concurrent changes • Changes history 

Version Control System • Tool for managing a *collection of files and its content. • *Collection is called a Repository 

When to VCS? • Almost every time you write code! • Great even for a single file 

Dvcs vs Cvcs master repo all repo are equal 

Dvcs vs Cvcs master repo all repo are equal 

Popularity in OS Eclipse Community Survey 

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Merge Conflicts 

Git Essentials 

Git is a DVCS • Everything is done locally (check in / commit / branch / merge) • Collaboration via repository sync • Peer to Peer approach (all repo are equal) • Stores history locally (Distributed Version Control System) 

Pros and Cons • Fast revision checkout • Offline usage • Local commits • Full control over VCS • Binary snapshot history • Repos can be heavy on first checkout due to local history • Hard to master 

Install Git • http://git-scm.com/ • http://www.sourcetreeapp.com/ Git itself: GUI app: 

Configure Git Credentials: • git config —global user.name alexey.buzdin • git config —global user.email [email protected] ~/.gitconfig - global REPO/.git/config - local 

[merge] tool = p4merge keepBackup = false [mergetool "p4merge"] cmd = p4merge "$BASE" "$LOCAL" "$REMOTE" "$MERGED" keepTemporaries = false trustExitCode = false keepBackup = false prompt = false [difftool] external = p4diff [push] default = current [credential] helper = osxkeychain [branch] autosetuprebase = always [user] name = alexey.buzdin email = [email protected] [mergetool] keepBackup = false prompt = false [alias] st = status [core] autocrlf = input excludesfile = /Users/alexeybuzdin/.gitignore_global [difftool "sourcetree"] cmd = opendiff \"$LOCAL\" \"$REMOTE\" path = [mergetool "sourcetree"] cmd = /Applications/SourceTree.app/Contents/Resources/opendiff-w.sh \"$LOCAL\" \"$REMOTE\" -ancestor \"$BASE\" -merg \"$MERGED\" trustExitCode = true vim ~/.gitconfig 

.gitignore # NuGet dependencies packages/ # Android module specifics **/Resource.designer.cs # Shared files **/bin/ **/obj/ *_ReSharper.*/ # Misc files *.user *.suo *.userprefs *.DS_Store *.swp # Migration .svn 

New Git Project • mkdir git-introduction; cd git-introduction • git init • git remote add origin https://github.com/LArchaon/learning-git-repo.git • git fetch • git checkout master 

New Git Project • mkdir git-introduction; cd git-introduction • git init • git remote add origin https://github.com/LArchaon/learning-git-repo.git • git fetch • git checkout master or • git clone https://github.com/LArchaon/learning-git-repo.git 

Git help • git help • git --help 

Git lifecycle 

Example • echo "Hello World" > a.txt • git status • git add a.txt • git status • git commit -m ”Initial commit” • git status • ??? 

Git lifecycle git add <filename> git add <filename> git commit git rm —cached <filename> 

Commit 

Branching 

Branching @ 

Navigation • git checkout 98ca9 • git checkout master • git checkout v1.0 • git checkout @ or git checkout HEAD 

Branching • git branch newBranch • git checkout newBranch or • git checkout -b newBranch 

Branching 

Branching 

Branching 

Merge 

Merge • git checkout master • git merge iss53 • enter commit message “C5” 

Merge 

Merging Pros • Simple to use and understand. • Maintains the original context of the source branch. • The commits on the source branch remain separate from other branch commits. This separation can be useful in the case of feature branches, where you might want to take a feature and merge it into another branch later. • Existing commits on the source branch are unchanged and remain valid; it doesn’t matter if they’ve been shared with others. 

Merging Cons • If the need to merge arises simply because multiple people are working on the same branch in parallel, the merges don’t serve any useful historic purpose and create clutter. 

Rebase 

if Merge done 

if Rebase done • git checkout experiment • git rebase master 

then • git checkout master • git merge experiment 

Rebase Pros • Simplifies your history. • Is the most intuitive and clutter-free way to combine commits from multiple developers in a shared branch 

Rebase Cons • Slightly more complex, especially under conflict conditions. Each commit is rebased in order, and a conflict will interrupt the process of rebasing multiple commits. With a conflict, you have to resolve the conflict in order to continue the rebase. • Rewriting of history has ramifications if you’ve previously pushed those commits elsewhere. 

Lets get hardcore! • git rebase --onto master server client 

more!!! “Check out the client branch, figure out the patches from the common ancestor of the client and server branches, and then replay them onto master.” 

then • git checkout master • git merge client 

morrreee…. • git rebase master server 

Success! • git checkout master • git merge server • git branch -d client • git branch -d server 

You feeling? 

• …. • git commit -m ”My commit” • git pull • git push 

Git pull • git pull = git fetch + git merge /branch 

Merge bubble • git pull = git fetch + git merge /branch 

• …. • git commit -m ”My commit” • git stash • git pull --rebase • git push • git stash apply 

Clean and pretty 

• git pull —rebase • git push 

• git pull —rebase int-mng master • git push int-mng master 

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http://git-scm.com/book/ 

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Countries Chapters Events 106 601 3222 

gdgriga.lv 

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https://developers.google.com/groups/ Find us at 

May 28 - 29, 2015 https://events.google.com/io2015/ 

May 28 - 29, 2015 https://www.youtube.com/watch?v=ksvdvCDO7pA 

Q&A Thank You!