Subversion

SVN Md. Maidul Islam

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

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)

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

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

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 statusany changes since revision n?

(resolve conflicts)

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

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...

Revision numbers

0 1 2 3

Revision number is increased for every transaction that changes the repository.

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

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

(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.

(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.

(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.)

Merging

Merging from a Branch Merge Tracking Best Practices

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 branchback to the main line.

RELEASE 1.0.0

BUGFIX_BRANCH

Merge back

267

RELEASE 1.0.1

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 branchnamebranchname

(1) The Subversion “merge”-command.(2) The revision in which we created the branch (267) and HEAD

for the complete branch.(3) The branch-name you like to merge into your current

working copy.

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 branchnamebranchname

(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

working copy.

Merge From a Branch via CLI

Extract the start point of the branch via CLI:

Merge From a Branch via CLI

Merging of a branch via CLI:

Merge From a Branch via TortoiseSVN

Merging of a branch via TortoiseSVN:

Merge From a Branch via TortoiseSVN

Merging of a branch via TortoiseSVN:

Merge From a Branch via TortoiseSVN

Merging of a branch via TortoiseSVN:

Merge Tracking

Merge tracking:

• Subversion does notnot 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.

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

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

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.

Feature Branches

• Separation by features (one branch each).

Feature 2

Main line

Feature 1

Thank You