Review your code like a Googler

All change lists must be reviewed. Period.

“Review your code like a Googler”

2013 Dariusz Łuksza

Dariusz Łuksza, [email protected]

@dluksza

mailto:[email protected]


Are you Git?

pre-requirements

First rule of Code Review:


Your code is not your wife...

pre-requirements

First rule of Code Reviewand OpenSource:


Your code is not your wife...

pre-requirements


Your code is not your wife...you can share it!

pre-requirements

First rule of Code Reviewand OpenSource:


I'm here for You!


Next ~47min.

● Code Review & Types● Post-commit vs pre-commit● The Gerrit● EGit + Mylyn Review Gerrit Connector● Command line→ ● Code Review Tips● Q&A

Code reviews with Gerrit by Mateusz Szczap@ Marmolana 14:50


Code Review

post-commit review(formal code review)





Flickr: markcph


https://secure.flickr.com/photos/markcph/2290878151/


Flickr: markcph


Coffee, absolute must have during formal code reviews

https://secure.flickr.com/photos/markcph/2290878151/


Flickr: sebastian_bergmann


https://secure.flickr.com/photos/sebastian_bergmann/3991539605/


Flickr: bike


https://secure.flickr.com/photos/bike/4299152140/


review on request(post- or pre-commit)


review on request(post- or pre-commit)

90 minlater

OK, so whereI was before...

Hi Jeff, could you review my changes

before I submit

I need a review...

OK, lets go!

Can I interrupt youfor a moment?You already

interrupted me...

Sure you can,what is it?

this loop iteratesover… mhm... and then

it brakes...

if (req != null) { for (i = 0; …if (...) break;

...

I finished my task and need finalcode review... would you like

to look on it?

emmmm … OK...

153 minlater

9 minlater

finally I can getback to my task...

… and then...


asynchronous review with Gerrit

(pre-commit)


Gerrit Code Review this loop iterates

over… mhm... and thenit brakes...

if (req != null) { for (i = 0; …if (...) break;

...

found it!! HAHAHA

OK, so now,commit and

push for review!

… step into...step over...

… step over...step over...

It's time to check othersreview requests

I'm invincible!!

Great! There are requestsfrom Tom, Sara and Jim...

let me see...

post-commitvs.

pre-commit


Flickr: bike2013 Dariusz Łuksza

post-commit vs. pre-commit

Flickr: sriram

VS.

https://secure.flickr.com/photos/bike/4299152140/

https://secure.flickr.com/photos/sriram/


The Gerrit

The Gerrit

● Created for Android OpenSource project● Designed to bring Google's code review feeling to

Android community● Pure Java based● Has vibrant community● Used in many OpenSource project's and Enterprise

companies● Can be used as regular Git server without code review● Supports branch based permissions● It is getting more and more extend-able



Who uses Gerrit?


let's play with Gerrit

Demo Time!

Preconditions:– You are joining new team with already existing

project

– Somebody already creates yours account in LDAP

– You already generated yours SSH key

– Already have Eclipse Kepler with EGit and Mylyn Gerrit connector installed


2013 Dariusz Łuksza2013 Dariusz Łuksza

fred

Meet Fred

First login into Gerrit




fredInsert yours credentials here





fred

Yours SSH public key goes here,remember to click 'Add'





fred

Finally, click 'Continue'





fredYou are logged in

Configure Mylyn Connector


fred

Add task repository



fred

If you don't have Gerrit connector on the list, use 'Install More Connectors' button

Select Gerrit and click 'Next'



fred

Provide server data

Validate before save

Finally, click 'Finish' to save new connection



fred

Of course I would like to create query for this connector



fred

Name the query

For our simple use case 'All open changes' will be enough



fred

After successful configuration you will see task repository and query in proper Eclipse views

Cloning project from Gerrit


fred

Clone project from Gerrit


fred



fred



fred



fred



fred



fred

Because in git repository there is no Eclipse configuration file (like eg. .project) we need to import it as 'general project'



fred



fred

Now we can import nested Maven projects



fred



fred

Create new feature branch


fred

Create new feature branch


fred

Create first change


fredChange something in repository

Create first change


fred

Remember to check generation of 'Change-Id' tagLeave this line as it is,

EGit will generate 'Change-Id' for you

Create first change


fred

Now push yours changes to Gerrit

Create first change


fred

Provide name of branch to which change should be merged after successful review

Create first change


fred

Create first change


fred

After some time you will see yours change on list of open changes


roman

Meet Roman

Review change


roman

Review change


roman

Double click on file will open a compare view

Review change


roman

Review change


roman

You can provide comments directly for each code line

Review change


roman

Review change


roman

Review change


roman

As you see Jenkins already have an opinion about this change

Review change


roman

You can publish yours comments using 'Publish Comments...' button

Review change


roman

Now you can provide yours vote and comment for this change


fred

Switch back to Fred

View incoming comments


fred

You will be informed about new comments on yours reviews

Abandon change


fred

If you push something by accident you can always abandon such change

Abandon change


fred


fred

Pushing multiple changes

Push multiple commits


fred

Create two or more commits in a rowand use standard EGit 'Push to Gerrit...' flow

Push multiple commits


fred

Gerrit will create separate review requests for each commit


roman

Switch to Roman

Review connected changes


roman

Of course you will see two open changes, let's review last one!



roman

Jenkins already verified this change, so let's merge it!



roman



roman

Last step is to push 'Submit' button



roman

Change was submitted, but it is not merged because it's parent change is still under review. It will be automatically merged after parent will be accepted



roman

Let's review second change



roman

Let's review second change



roman

Of course it was merged successfully



roman

Of course it was also merged successfully

Wat is going with previously submitted change?


roman

Roman goes to Bahama(continue other's work)

Continue other's work


fred

All changes are stored in Gerrit, you can fetch each patch set version when ever you want to



fred

Provide meaningful branch name and click 'Finish'



fred

Done, you have Roman's changes locally and can continue his work

Code Review Tips● Be constructive, don't hate, always propose or point to

solution

● Don't take comments personally, they are only about code and how you can improve, code and your skills

● Code review is like refactoring of code that you have written long time ago … you need to understand author's intention

● It's like TDD, review code before it hit main repository. This will guarantee the best application quality

● Do code review on daily basis … remember when you are not reviewing other's code then application is not progressing



Dariusz Łuksza, [email protected]

@dluksza

“Review your code like a Googler”

Q&ASlides can be found at: http://goo.gl/R3Vfk

mailto:[email protected]

http://goo.gl/R3Vfk


BTW. Don't forget about DevCrowd conference in Szczecin in 2014. More

info you can found at: http://devcrowd.pl

http://devcrowd.pl/

Technology

Review your code like a Googler