After many years of faithful use of Subversion as our version control system of choice, we found the need for something more flexible that could better scale with the many code trees we manage across our engineering organization. In this talk, I’ll talk about how using Subversion for version control wasn’t doing it for us anymore, the move to using Git and GitHub (and the challenges along the way), and the various wins we have gained as an engineering organization and with our partner and community developers.

1. Subversion to Git: A Sugar Story
John Mertic
©2012 SugarCRM Inc. All rights reserved.

2. Who Am I?
! John Mertic
! Contact Info
! http://
jmertic.wordpress.com
! Twitter: @jmertic
! jmertic@sugarcrm.com
( SugarCRM )
! jmertic@php.net ( PHP )
! Community Manager for
SugarCRM
! http://www.sugarcrm.com
! http://www.sugarforge.org
! Twitter: @sugarcrmdev
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3. Why we started looking past Subversion
! Merging was painful
! Couldn’t easily work on multiple releases at once
! Couldn’t do feature branch integration easily
! Merging cost us several days of downtime plus integration
testing
! No good way of doing pre-commit reviews
! Tried using Review Board for post-commit reviewing, but
was ineffective
! Pre-commit reviews required manual posting of diff files and
manual merging
! Overall, felt Subversion could scale to match our
growing team.
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4. Why git?
! Wanted to move towards a
DVCS tool to support our
growing team
! Best quality of tools and IDE
plugins across the various
DVCS tools.
! Many team members already
familiar with git, which helped
train other team members
! GitHub
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6. Approaches to SVN to Git Migration
! Physically migrate existing
SVN repository
! Helps maintain history
! Allows you to quit SVN cold
turkey
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8. The approach we took
! Start fresh with git
! Allowed us to re-think our code structure
! Got rid of lots of old and unused code
! Avoided the problems of doing a migration
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9. Import SVN Have devs
Export SVN export into change Setup SVN
Create new newly from svn
working mirroring
git repo
copy created git checkouts from GitHub
repo to git clones
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10. Why GitHub?
! Wanted offsite secure code hosting provider
! Very easy to use web based management of
repository
! ACL
! Simple file changes can be done online
! Visual history management
! SVN read ( and now write ) access for legacy clients
! Pull requests and forking made simple
! Enables pre-commit reviewing easily
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11. How did it go initially?
! #wins
! Average time to do a merge went down to about an hour
! Fewer conflicts
! Apply a fix to multiple branches now takes a minute
! No longer a manual process
! #fails
! Had to rethink our initial branching strategy
! More on this later
! Challenging for developers working on older and newer
releases at the same time
! Resolved once older releases went away
! Learning curve for git tools
! Took around 6 months before team was really proficient
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12. What have we gained?
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13. Pull Requests!
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14. Advantages of Pull Requests
! More natural approach to pre-commit code reviewing
! Uses git forks to enable pushing commits up to main
repository
! Enables true two-way peer review
! Inline commenting
! Can directly track submitter and reviewer
! Easy for submitter to update pull request
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15. New initiatives due to Pull Requests
! Open+ Developer Program
! Enables our VAR and ISV partners to have direct access to
the Sugar codebase.
! They can contribute fixes directly to us that we can review
and accept into the product
! Community Branch
! Allows our community members to make pull requests
against our open source version, that we pull into the
product
! Both initiatives has resulted in over 100 code
contributions over the last year, over 5x as much as
the previous year.
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16. Change in branching strategy
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17. What we did back in SVN
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18. Now what we can do with git
! Feature branches that aren’t painful to merge
! Bug fix dumping ground branch that we can pull fixes
from to build maintenance releases
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19. Git branching strategy
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20. Takeaways
! Git solved the scalability needs that Subversion didn’t
! Enables more distributed development with less integration
time
! Allows us to define our branching strategy less around the
tool and more around the process
! Moving to Git without migrating old commits was a
#win
! Unshackled us from the SVN paradigm of the past
! GitHub is a kick butt tool
! Provides tools to make code reviews better and fit more into
the natural flow of development
! Easily enables community around your codebase
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21. Questions?
©2011 SugarCRM Inc. All rights reserved.