1. Branching and Merging Practices
Tech Ed North America 2010
11/27/2018 6:50 PM
Required Slide
SESSION CODE: DPR303
Branching and Merging Practices
Jeff Levinson
Senior ALM Consultant
Northwest Cadence
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

2. Branching And Merging Agenda
What are we trying to solve?
Basic branching patterns and scenarios
Branch by Release
Branch by Quality
Branch by Feature
Selecting patterns to meet business needs

3. What problems does branching solve?
Know what code was released
Don’t release code that isn’t ready
Allow developers to experiment
Independent construction of features
Code freeze
Bottom line… reduce risk

4. Branching Patterns

5. Branch By Release (Staircase)
Maintain releases separately
Allows for fairly easy promotion of fixes which effect multiple versions
Easy handling of test cycles and timing
Can be used for single releases (as in a web application)
Can be used for multiple releases (having to maintain multiple versions at the same time)
Development
Test
Production R1
Branch
On Test R2
Branch
On Test R3
Branching / Merging
point
Development
LEGEND
Test
Production

6. Branch By Release (Staircase) Handling bugs
Development
Test
Production
Integration is always forward R1
Forward
Integrate as
necessary
Forward
Integrate as
necessary
Branch
On Test R2
Forward
Integrate as
necessary
Branch
On Test R3
Branch
On Test
Branching / Merging
Point R4
Development
LEGEND
Test
Production

7. Pros Cons Staircase Thoughts Simplest model to use
Good choice for single version web applications
Same pattern for hot fix or maintenance release
Minimal amount of branching
Cons
Not as flexible as other patterns
More active releases = more difficulty doing Forward Integration
Multiple test environments needed
Doesn’t support multiple concurrent releases well
May have to re-create the builds for new releases

8. Branch by Release (Mainline)
Effectively supports multiple concurrent releases
R1.1 R1
FI for Release
FI for Release
Main R2
R2.1
Branching / Merging
point
Release Branch
LEGEND
Development

9. Pros Cons Mainline Thoughts
No dependencies on any version except the prior .x version
Cons
Branching can get very complicated
Requires numerous merges and active management
Requires numerous test environments
Initial release from main, subsequent releases from release branch
Forward integrating bug fixes is difficult

10. Branch by Release
Demo

11. Branch by Quality Flexibility Minimal number of branches
Supports the maximum number of scenarios
Minimal number of branches
Handles complex situations
Though not always easily
Numerous variations to meet various needs
Prod
Firm
Branch QA
Branch
Soft
Dev

12. Branch by Quality - Variations
Permanent Hotfix
Safekeeping
Prod R1 R2
Branch
Prod QA
Branch
Branch
Hot Fix QA
Branch
Dev
Dev

13. Bug Found In Test Straightforward fix strategy Very easy, very quick
Prod Rx
Branch
Code under test L1 L1 L2 QA
What happens if a bug then occurs in production? FI
Branch RI
Hot Fix
Dev R1 R2
Branching / Merging
point
Multiple steps
done as a single
unit of work
LEGEND
Branching / Merging
Point + Label X
Bug found

14. Bug Found In Production Fixed on QA Branch
Rollback to L2
Code under
test
Code under
test
Code under
test
Branch L1 L2 L3 L2 L4 L5 QA
Branch
Dev D1 D2 R1 R2 R3
When the rules don’t work – break them
But understand why!
Branching / Merging
point
Multiple steps
done as a single
unit of work
LEGEND
Branching / Merging
Point + Label X
Bug found

15. Branch by Quality thoughts
Pros
Maximum flexibility
Easy ability to deal with multiple branches
Supports multiple paths to production (multiple test environments, fixes from different branches)
Cons
Can be extremely complex
Requires a dedicated build person
Without documented processes, can spiral out of control and you can “lose” source code because you can’t find it!

16. DEMO Branch by Quality Tech Ed North America 2010 11/27/2018 6:50 PM
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

17. Branch By Feature Isolate features for various reasons
Longer time to develop
Won’t fit in an iteration
Independent of other features
Allows for release of features as ready
No dependency on when other features are ready
Provides additional options on top of Branch by Quality pattern.
PROD QA
DEV F1 F2 F3
Branching /
Merging point
Multiple steps
done as a single
unit of work
LEGEND

18. Branch by Feature Thoughts
Pros
Separates out features
Allows for flexibility in release
Allows for easier debugging (a problem with one feature doesn’t effect another feature)
Builds on the Branch by Quality pattern
Helps deal with longer running features
Cons
Can get as complicated as Branch by Quality
Feature teams need to remember to sync often with dev branch
Can get confusing for teams working on multiple features
Requires at least one test environment per feature
May need multiple integration branches

19. DEMO Branch by Feature Tech Ed North America 2010 11/27/2018 6:50 PM
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

20. Discussion Scenarios What to consider when deciding on a strategy
Tech Ed North America 2010
11/27/2018 6:50 PM
Scenarios
What to consider when deciding on a strategy
Discussion
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

21. Scenarios What to consider when deciding on a strategy
Customer can’t make up mind
Branch by Feature, but include test integration branches
Concurrent releases, not sure which feature in each release
Branch by Release (mainline) + Branch by Feature
Maintain only one release, short release (dev & test) cycles
Branch by Quality
Maintain only one release, long release (dev & test) cycles
Branch by Release

22. Any scenarios you want to discuss?
Question & Answer
Any scenarios you want to discuss?

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© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

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Tech Ed North America 2010
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© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

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26. Tech Ed North America 2010 11/27/2018 6:50 PM
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

27. Required Slide Tech Ed North America 2010 11/27/2018 6:50 PM
© 2010 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.
The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.