Migrating to Git:Let's Git this party started

@Kim_ Moir@paulweb515

IBM Ottawa

Git Happens

@Kim_ Moir@paulweb515

IBM Ottawa

About Us

• 10 year old code repository

• Around 40 active committers

• Produce approximately 600 bundles a build

• Limited Git experience before migration

Active development streams: 4.2, 4.1.x, 3.8, 3.7.x

Unix group (guid) -> Git repo

2 CVS repos -> ~25 Git repos

CVS :

• Condition

• Copy to temporary location

• Run cvs2git

Git:

• git fast-import CVS content into temporary Git repository

• Git-move-refs

• git prune, repack, gc and repack

• Validate the git repo

• Run a script to remove delete only tags

• Add gitignore file via git filter-branch

• Clone into bare repo

• git prune, repack, gc and repack

• copy repo into final location

“It’s one thing to migrate to Git, it’s another thing to use it”

-Olivier Thomann

“Git: The command line is where it’s at”

-Bogdan Gheorge

“Patches are like dumping a database into a text file. You need to think in terms of releasing fixes to branches instead of passing around patches. Patches also lose some Git provenance information such as author and parent.”

-J ohn Arthorne

“That operation is four pay-grade levels above my current git-foo.”

-Paul Webster

“I have broken the platform-ui git repository.”

-Bug 361707

“Better policy to guard against deleting all branches and tags from our public repos”

-Bug 362076

“There are three categories of costs that we incurred during the Git migration:

The migration process itself, the developer learning curve and dealing with EGit issues”

-Mike Wilson

•Read•Test migration•Communicate

“The complexity of our code is the barrier to contribution, not the S CM”.

-Paul Webster

Useful links• Git parable http://tom.preston-werner.com/2009/05/19/the-git-parable.html

• Pro Git Book http://progit.org/

• Think like a git http://think-like-a-git.net/

• Managing large binary files with Git http://stackoverflow.com/questions/540535/managing-large-binary-files-with-git

• Git workflows for CVS users http://wiki.eclipse.org/Platform-releng/Git_ Workflows

• git@eclipse.org mailing list

• E Git Documentation http://eclipse.org/egit/documentation/

• Migration scripts we used git://git.eclipse.org/e4/org.eclipse.migration.git

• Git flow discussion http://dev.eclipse.org/mhonarc/lists/eclipse-dev/msg09229.html

Questions?

“Git happens”

-Kim Moir

-Paul Webster

Give F eedbac k on the S es s ions

1 S ign In: w w w .ec lips ec on.org

2 S elec t S es s ion E va luate

3 Vote

Image credits• Beach http://www.flickr.com/photos/archer10/2218592521/sizes/

• Reading room in British Museum http://www.flickr.com/photos/cliveabrown/2258478542/

• Blackbirds at dusk http://www.flickr.com/photos/moonjazz/1216783552/

• Binary bridge at Georgia Tech http://www.flickr.com/photos/mcclanahoochie/5068845349/sizes/l/in/photostream/

• Branches http://www.flickr.com/photos/e_ phots/3012896283/

• Git stash http://www.flickr.com/photos/dealingwith/4295488113/

• Fork you http://www.flickr.com/photos/sunfox/4365495446/sizes/l/in/photostream/

• Rethink http://www.flickr.com/photos/venegas/5549123/

• Gears http://www.flickr.com/photos/wwarby/4782904694

• Git gas station http://www.flickr.com/photos/soo/6047596987/

• Advice http://www.flickr.com/photos/wurzle/659315/

• Fraser river delta http://www.flickr.com/photos/ecstaticist/3055718118/

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