The new version control system

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• The new version control system

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What is Subversion

• Subversion is a newly developed open source
  version control system
• Subversion enhances upon the proven CVS
• Subversion is free
• Subversion is available on nearly all platforms

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Why Subversion

• Versioning of the whole repository not only files
• Support for both concurrent access and locking
• Support for attributes on all object files,
  folders and revisions
• Optimized for distributed use

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Why Subversion II

• Updates are done in atomic transactions
• One version of the repository includes updates to
  multiple objects
• Operations like branching and tagging are
  extremely efficient

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What is Revision in Subversion

• Revisions contain a set of modifications to a set
  of files/folders i.e. One revision refers many
  files
• User can see which files are modified in parallel
• Revision numbers are global for the repository
  each commit/check-in increases the version of the
  repository
• Easy reversal of modifications as each commit can
  be reverted to separately, there is not issue
  with differentiating commits that occurred
  approximately at the same time

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Concurrent Work

• Subversion supports the two currently popular
  models for dealing with concurrent development
• Concurrent edits (similar to CVS) a.k.a.
  copy-modify-merge
• Locking of files (similar to SourceSafe)
• Both models can be used on the same repository at
  the same time giving an additional degree of
  control

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Metadata to all objects

• SVN supports properties that can be associated to
  all objects
• Files
• Folders
• Revisions
• A property is combination of name and value
• All properties are versioned except those
  associated with revisions
• Properties can be useful to
• Identify resolution to defect in tracking system
• Track the status of particular revision i.e. self
  reviewed, unit tested, inspected by peer etc.

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Accessing Subversion

• Subversion can be accessed
• Using SVN client over HTTP/HTTPS by extending
  Apache web server
• Using proprietary network protocol
• Using shared file system
• Latest version of files in Subversion can be
  accessed using regular web browser!

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Subversion clients

• TortoiseSVN easy to use integrated with Windows
  Explorer client, has a built in diff tool
• Subclipse - Integrated in Eclipse client
• Several standalone desktop clients
• Of course UNIX style command line

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Downsides

• Problem with web projects and Visual Studio 2003
• A bug in Visual Studio 2003 prevents it from
  operating when using subversion on web projects
• Updates to the product are a bit too frequent
• Concurrent editing model may be frustrating to
  SourceSafe users

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Trac

• A web based system to complement Subversion with
• Wiki
• Issue tracker
• Friendly web access to revision control
• Basic reports
• It is possible to cross refer Subverison items
  with Wiki and Issues

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Trac plus/minus

• Positive
• Very nice web UI
• Integrated with subversion
• Easy to learn
• Plug-in system

• Downsides
• Admin UI is incomplete forced use of command line
• Plug-in system is problem in maintenance

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Further reading / Questions?

• Subversion site - http//subversion.tigris.org
• TortoiseSVN - http//tortoisesvn.tigris.org/
• Tracs web site - http//www.edgewall.com/trac