Formal Specification of the Subversion Version Control System in Z

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Formal Specification of the Subversion Version
Control System in Z

• 
  Zhongbo Huang (Jerry)
• 41184963
• Supervisor Annabelle
  McIver

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Workshop Presentation Outline

• 1. Introduction -- Subversion
• 2. Formal Specification --Z notation
• 3. Case Study -- Case scenario
• 4. Outcome of Project
• 5. Conclusion and Limitation

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1. Introduction --VCS

• Version Control System ( Revision Control System)
• Version Tracking
• Coordinating Teams
• Every change made to the source is tracked, along
  with who made the change, why they made it, and
  references to problems fixed, or enhancements
  introduced, by the change.
• an excellent way to combat the problem of sharing
  files between workers.

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1.Introduction--Subversion
Subversion Control system a centralized system
for sharing information. Allow many users to
share but work independently on the same
document. The repository remember every change
to every file and directory tree itself. It will
also merge users files to produce a single merged
copy recording all their modifications. The key
feature operation Update Operation Commit
Operation
Merge
Share
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2. Formal specification Z notation

• Formal specification is the use of mathematical
  principles to describe precisely the desired
  behavior of computer systems.
• Z notation
• Base on simple set theory, predicate logic,
  relation and function.
• Specify the requirements or behavior of systems.
• Analyze that behavior via proof, animation, test
  generation

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2.Z notation - example

• SVNFILE String
• f, f SVNFILE
• af ?, bf ! SVNFILE
• SVNFILE FileName x FileNo

Z notation
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2. Z notation- Schema example
Schema Name
f represent before operation, f represent
after operation.
Declaration
By convention names in the declarations ending
in ? are input and names ending in ! are
outputs.
Read operation doesnt change file
Predicate
fna! and fno! as the output equal to the first
and second pair set of f
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3. Case Study Case Scenario

• Alice and her collaborator, Bob, are working
  together on a small project (recipe), and using
  Subversion repository to share their work.

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3. Case Scenario Update and Commit Operation
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4.Outcome of Project

• Report detailing the enough specification of the
  key of features of Subversion using Z language,
  together with a commentary on the design
• The goal of this project was to understand and
  clarify Subversions behavior and what user can
  expect when he/her uses it.

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4.Outcome -- Update Operation
af, af represent Alice working copy from
project repository
rf? as input from project repository
Alices working copy update to project repository
the output f! and arn! represent the latest of
File and SVNRevisionNo in the SVNFile repository.
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4.Outcome Commit Operation
rf, af represent the state before the operation.
rf,af represent the state after the operation.
af? as input from project repository
Bobs working copy commit to project repository
This line notation address the revision number in
rf and bf increment after commit operation
successfully.
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5.Conclusion and Limitation

• Conclusion
• Lead to a well-though-out, well-structured
  program
• Provides an unambiguous statement of intent
• Act as documentation for the finished program,
  helping those who have to maintain and update the
  program in the future.
• Limitation
• Do not include all the details involved
• Some formal specification in this project may not
  be carefully considered or even wrong explanation
  because of limitation of personal capability and
  scheduled time.

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The End of Presentation
Question ?
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