Advanced Branching and Merging

We will begin in a few moments

Presenter

Michael LesterWandisco

Director of Training

Advanced Branching and Merging

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Outline

Definition of concurrent development

What is a branch What triggers a branch Not all branches require a merge

Branching Demonstration Types of Merges How to do a merge Merge info

Merging Demonstration Conclusions

This training is done with the latest TortoiseSVN Version

http://www.wandisco.com/subversion/download

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Concurrent Development

Definition When the same code/project has multiple developers working at the same time.

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Concurrent Development

Subversion tools that support concurrent development

Branching

Merging

Author identification

Hook scripts

Difference reporting

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Who changed / created / deleted what

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Who changed / created / deleted what

Author information is availablethrough svnlook command

And statistics

svnlook author -r 40 /var/svn/repos

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What is a Branch

The basic concept of a branch:

A line of development that exists independently of another line

A branch always begins life as a copy of something, and moves on from there, generating its own history.

Original line of development1st branch

2nd branch

3rd branch

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Reasons for Branching

• Releasing patches for systems already in production.

• Preparing interim releases for testing and user evaluation.

• Working on more than one major version of the same code-base.

• Major changes require independent development

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Release patches (bug-fix)

Payroll application

Trunk

Rel 1.0

Trunk

Rel 1.0

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When to branch

• Concurrent development• To isolate development

• To create tag projects• Keep track of released code

• Custom branch• Limited use• To test unapproved changes

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When NOT to branch

• Small changes

• From “TAGS” folder

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Branching from working copy

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Branching from the TAGS folder

Pros and Cons

There is a bug in Rel 1.0What do you do?

1. Create a bug fix branch1. Create a bug fix branch2. Fix the bug1. Create a bug fix branch2. Fix the bug3. Create another “release”

tags folder branchCheck out

Edit

Update

Commit

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Extending the TAGS folder

Pros and Cons

There is a bug in Rel 1.0What do you do?

Check out

Edit

Update

Commit

1. Checkout and Commit to the Rel1.0 branch

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How do you keep track of “What is the actual release”

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Identifying Branches in Subversion

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Deleting Branches

Remember:The directory (project) can always be recovered, but willnot display in the list command unless a specific revision (53) is specified.

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Merging in actionBug fix / concurrent development

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Merging in action

Now the branch changes

While the trunk changes

onetwothreefourfivesixSeveneight

onetwotwothreefourfivesixSeven7eight

onetwothreefour5sixSevenEight

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Merging in action – modification occurs

After both commits

mike-bigfix-01172011

Trunk

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Merging in action

You always start from a working

folder

mike-bigfix-01172011

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Merging in action – changes are made

onetwotwothreefour5sixSeven7eight

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Merging in action – Commit to trunk

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Merging in action – mergeinfo

The property svn:mergeinfo is added automatically

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Merging in action

The revision numbers 9 – 11 are the starting and ending changes in the branch

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Merge information

You can view the branchinformation graphically

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Merging in action – collision ahead

Now the branch changes

While the trunk changes

onetwothreefourfivesixSeveneight

onetwotwothreefourfivesixSeven7eight

onetwo22twothreefour5sixSevenEight

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Merging in action

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Merging in action

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Merging in action – Resolve the conflict

Before you can do a commit you must tell Subversion that the conflicts have been resolved

Remember – you still have to do a commit to update the repository

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Special merging situations – no change in trunk

After branch changes

bigfix-20311

Trunk

7 8

1211

9

13 14

Do I have to merge ?Check out the trunk HEAD version

Merge like normalsvn:mergeinfo /payroll/bugfix-20311:11-14

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Using the hidden menu to merge

Shift/right click

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Include merged revisions in Log Messages

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Command line mergeinfo command

C:\source\newFeature>svn mergeinfo c:\source\payroll --show-revs mergedr15r18

C:\source\newFeature>svn mergeinfo c:\source\payroll --show-revs eligibler21

This can be used to show what has been merged and what could be merged

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Cherrypicking

This refers to choosing one specific changeset from a branch and replicating it to another.

TRUNK

Custom Branch

This fixed a bug

reproducable in the trunk This added a

new feature for a unique

customer

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Cherrypicking

How does the other branch find out about the useful code?

I fixed a bug in my custom project that probably

exists in the trunk.

It was logged as bug fix 1655.

Something about “customer sort”.

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Another reason for Log Messages

How does the other branch find out about the useful code?

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Searching for log messages

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Merge from log messages

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1. Practice

2. Practice

3. Add branching and merging to “Policies & Procedures”

4. Train staff

5. Revise your policies & Procedures

Conclusions

43Copyright © 2013 WANdisco.com All rights reserved.

Presenter

Michael LesterWandisco

Director of Training

April 4th

SubversionAdministration

April 18th

Introduction to SmartSVN