SVN - Basic Concepts What is Version Control System? how it works ? Working Style :)

1. SVN
Rahul Tripathi

2. What is version control?
Version management allows you to control and monitor
changes to files
What changes were made?
Revert to pervious versions
When were changes made
What code was present in release 2.7?
Earliest tools were around 1972 (SCCS)
Older tools – RCS, CVS, Microsoft Source Safe, PVCS
Version Manager, etc…
Current tools – Subversion, Mercurial, Git, Bazaar

3. We will use subversion (svn)
Why?

Because it’s popular
It’s well supported
IDEs - Netbeans, Eclipse
Numerous GUI tools
Command line
XP Dev has support for it (you will use this for your semester
projects)

4. subversion concepts
checkout – get a local copy of the files
I have no files yet, how do I get them?
add – add a new file into the repository
I created a new file and want to check it in
commit – send locally modified files to the repository
I’ve made changes, how do I send them to the group?
update – update all files with latest changes
Other people made changes, how do I get them?
tag / branch – label a “release”
I want to “turn in” a set of files

5. Creating a new repository
Command Line:
Open command prompt
Go to a directory where you want your files to be stored
svn checkout <<location>>/svn/<<your project>>/

GUI Mac OSX SCPlugin
Adds commands to right-click menu in Finder

GUI Windows Tortoise SVN
Adds commands to right-click menu in Explorer

6. How to Use Version Control
checkout (first time)
(do some work, test)
update
commit
(do more work, test)
serverclient
send current revision ( n )
update your local copy with any
changes in the repo.
save your changes and log entry
check status
any changes since revision n?
(resolve conflicts)

7. tags
branches
trunk
Project 1
Root
Project 2
Subversion Repository Layout
tags
branches
trunk
tags
trunk
Project 1
Repository parent dir
Project 2
tags
trunk
One repository, many projects One project per repository
branches
branches

8. Subversion "repository"
Typically one "repository" per project.
Server can have an unlimited number of
"repositories".
/var/svn/kuclock
revision 1
(initial repo structure)
revision 2
revision 3
revision 3:
content diffs
author
date
reason for change (comment)
revision 4
"KUClock" Project Repository
revision 2:
initial project check-in
...etc...

9. Revision numbers
0 1 2 3
Revision number is
increased for every
transaction that
changes the repository.

10. Properties of a Repository
History of all changes to files and directories.
you can recover any previous version of a file
remembers "moved" and "deleted" files
Access Control
Read / write permission for users and groups
Permissions can apply to repo, directory, or file
Logging
author of the change
date of the change
reason for the change

11. URLs and Protocols
http://myhost.com:port/path/to/repository
Protocol:
svn
svn+ssh
http
https
file
Host name or
IP address
127.0.0.1
localhost
host:8443
optional port
number
Repository
relative
path

12. (1) Check Out using TortoiseSVN
Using Windows Explorer, right-click in a directory.
If not sure of path to check-out
then use Repo-browser first.
In Repo-browser, right-click on
folder or file you want to check-
out.

13. (1) Check out using Eclipse
Many ways to do it. Here is a simple way:
1. Switch to "SVN Repository Exploring Mode".
2. Right click and choose
New => Repository Location
3. Enter URL and (optional)
authentication info.

14. (1) Check out using Eclipse
Now you can browse the repository.
Choose the part you want to check-out
(usually "trunk")
Right click and choose "Check Out as..."
("Check Out as..." gives you a chance to
change local project name if you want.)

15. Merging
Merging from a Branch
Merge Tracking
Best Practices

16. Merging From a Branch
•What’s with the bug you've fixed on the bug-
fix-branch?
•What about your current development?
•You have to merge the
•changes made in the branch
•back to the main line.
RELEASE 1.0.0
BUGFIX_BRANCH
Merge back
267
RELEASE
1.0.1

17. Merge From a Branch via CLI
You can merge the changes from the branch
into your current working copy with the
following command:
svn merge -r 267:HEAD branchname
1)The Subversion “merge”-command.
2)The revision in which we created the branch (267) and HEAD
3) for the complete branch.
4)The branch-name you like to merge into your current
5) working copy.

18. Merge From a Branch via CLI
You can find the revision number when the
branch was created using the command:
svn log --verbose --stop-on-copy branchname
1) The Subversion “log”-command.
2) Print out much information (verbose).
3) Stop the log-output at the revision the branch was copied.
4) The branch-name you like to merge into your current
5) working copy.

19. Merge From a Branch via CLI
Extract the start point of the branch via CLI:

20. Merge From a Branch via CLI
Merging of a branch via CLI:

21. Merge From a Branch via
TortoiseSVN
Merging of a branch via TortoiseSVN:

22. Merge From a Branch via
TortoiseSVN
Merging of a branch via TortoiseSVN:

23. Merge From a Branch via
TortoiseSVN
Merging of a branch via TortoiseSVN:

24. Merge Tracking
Merge tracking:
•Subversion does not have any function to
track merges that have already been done,
•i.e., to prevent you to merge a branch a
second time.
•You have to do it yourself!
•Example: after merging, create a README-
merged file in the branch stating that it was merged
into trunk revision r99.

25. From the technical view branch and tag are the
same.
BUT:
•The intention of a tag is that it should be used as
read-only area whereas a branch is used to
continue development (interim code, bug-fixing,
release candidate etc.).
•Technically you can use a tag to continue
development and check in etc. but you shouldn’t
do it.
•So in other words the difference between a tag
and a branch is just an agreement.
Merge Warning

26. Developer Branches
•Separation of team members can be realized
with branches.
•One branch per team member or several
members on a branch - the decision is based
on the size of the teams.
Member 2
Main line
Member 1

27. Developer Branches
•Advantages using branches for team work:
•No changes during development on the main line
needed => Code stability.
•Every team member can work in its own environment.
•
•Disadvantages:
•Sometimes the mainline and the branch will diverge if
the branch lives too long.

28. Feature Branches
•Separation by features (one branch each).
Feature 2
Main line
Feature 1

29. Thank You