CoxR: Open Source Development History Search System

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CoxR Open Source Development History Search
System
Makoto Matsushita, Kei Sasaki, and Katsuro Inoue
Osaka University
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Contents

• Background
• Open-source software development
• Repository analysis system CoxR
• Supporting Dynamic Communication System
• Future research interests

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Open Source Software Development

• Open and parallel software development
• Anybody join the party at anytime
• Developers are living all over the world

source code
source code
source code
source code
source code manual
CVS
email
requests
requests ? fixes
developers
email archives
submit bug-report request feature enhancement
GNATS
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Reusing repositories

• System repositories have valuable information
  such as products evolutional histories and each
  developers information
• processes to be done to products
• knowledge on requirements and design
• Analyze and reuse these contents may help to
  reduce time/efforts of whole software development
• reuse the ways of bug-fix
• understanding a project itself that are going to
  join
• reuse (a part of) products/components
• However, there are some difficulties to reuse
  contents

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Problem 1less relationship between systems

• Where can I find what I want?

It seems that bktr driver has a bug so Id like
to fix it
user
files also need to be changed
proposed fix for bktr driver
discussions on bktr driver
source code fixes
CVS
GNATS
email archive
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Problem 2Interests may vary

• Even if the problem is same, a solution that is
  done in the past is not suitable for all peoples
• knowledge and processes may vary for developers
• information needs may vary on time

Maybe similar bugs were appeared on other drivers
so search them up
Problem theres a bug on bktr driver
Id like to seek authorities of graphics driver
Id like to have a new version of bktr driver
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Objective

• Analyze past processes/histories kept on existing
  systems, to help developers to search,
  understand, reuse such processes
• Modeling information on systems as development
  community, using CVS, Email, and GNATS
• Propose an information extraction approach from
  development community
• A prototype of the proposed approach

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Topics

• Step 1 Modeling information
• Step 2 Information extraction algorithm
• Step 3 System implementation

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Model elements

• People developers registered to CVS, email
  archive, and GNATS databases
• Knowledge contents of CVS, E-mail, and GNATS

integrated model
email archives
GNATS
CVS
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Extracting people/knowledge
Knowledge
?
file path revision tag, date
source code comments
developer contributor
CVS
Subject body
From To, Cc
Message-Id Date
E-mail
modification
base
file path PR date last modified
Originator Responsible
fix audit-trail status
category bug class description
GNATS
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People/Knowledge network

• We assume that the network has 3 types of edges
• People-Knoledge
• People-People
• Knowledge-Knoledge

Development Community
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Extracting network edges (1/2)

• People-Knowledge edge
• People/Knowledge elements in the same CVS, Email
  and GNATS information
• People-People edge
• Peoples in the same CVS, Email, and GNATS
  information
• Peoples subscribed to the same lists
• Peoples working on the same directory

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Extracting network edges (2/2)

• Knowledge-Knowledge edge

• Directly connected
• Revision histories to the same file
• Files in the same directory
• Modified at the same time
• Email threads
• Email/PR IDs

• Similar Knowledges
• Source codes
• Keywords
• Base/modification information in GNATS

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Topics

• Step 1 Modeling information
• Step 2 Information extraction algorithm
• Step 3 System implementation

Finding out a small network that is matched to
the users input
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Topic community

• Topic reusable process and information
• Elements related to a topic can be defined as a
  sub-network of development community
• Topic community may vary to each user

development community
Experts on this area
patches
Topic communmity
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Topic community extraction (1/6)

• Select the initial knowledge elements
• Assume that a topic is given by a user
• Extract knowledge matched to the topic
• Select an initial knowledge elements

I found that there is an register error on bktr
driver while watching TV by fxtv program
Code fragments Directory/file name Mailing lists
name Bug class/description Keywords Date
CVSbktr_core.c 1.20 Comment fix register error
Keyword bktr
E-mailSubject bktr module unloding (2002)
user
GNATSDescription fix bktr option error (2000)
Search results
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Topic community extraction (2/6)

• Select the initial knowledge elements
• Assume that a topic is given by a user
• Extract knowledge matched to the topic
• Select an initial knowledge elements

It seems that bktr_card.c rev. 1.20 is good
CVSbktr_core.c 1.20 Comment fix register error
E-mailSubject bktr module unloding (2002)
user
Select bktr_card.c
GNATSDescription fix bktr option error (2000)
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Topic community extraction (3/6)

• Show related people/knowledges using the network
• User selects appropriate elements again

Id like to know the people working on bktr_core.c
developer fjoe
bktr_core.c
contributor phk
Search results
user
Search related elements
contributor roger
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Topic community extraction (4/6)

• Show related people/knowledges using the network
• User selects appropriate elements again

developer fjoe
Hmm, fjoe is actual developer so I want to know
more about him.
bktr_core.c
contributor phk
Select fjoe
user
contributor roger
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Topic community extraction (5/6)

• Search and select elements repeated

Variables changed in yuv422_pro()
Same time changed bktr_card.c
Ok, are there any other elements that when fjoe
changed bktr_core.c
developer fjoe
bktr_core.c
Search results
user
Search related elements
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Topic community extraction (6/6)

• Search and select elements repeated

Tracking GNATS elements that is talking about
bktr_card.c
Variables changed in yuv422_pro()
Same time changed bktr_card.c
GNATS PR41437 (closed) DescriptionProblems
bktr_card.cyuv422_pro()
developer fjoe
bktr_core.c
Email commented to the change
PR41437 causes a register error
Search results
Topic community
user
The user finally get information about the
changes to bktr_card.c, that helps to fix
register error
Search related elements
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Topics

• Step 1 Modeling information
• Step 2 Information extraction algorithm
• Step 3 System implementation

CoxR web-based system, using FreeBSD data
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CoxR implementation

• Using FreeBSD development data, from 1994 to 2004
• System development environment
• CPU Pentium4 1.5GHz
• RAM 512MB(SDRAM)
• OS Debian GNU/Linux
• System size about 10000 LOCs

CVS FreeBSD CVS repository (Total 57822 files,
618186 revisions) E-mail Commited changes
mailing lists (Total 213723) BTS FreeBSD
GNATS PRs (Total 82350)
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System overview
Topic words
Web Server
Search results
selection
user
System Control
History DB
Matched People/Knowledge
Knowledge-Knowledge relations
People-Knowledge relations
People-People relations
Information Extraction
Knowledge People
Relation DB
Knowledge People
CVS
E-mail
Relation extraction
GNATS
CoxR-C
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System evaluation

• Purpose
• CoxR provides useful information to developers
  with appropriate search results
• Process
• Announcing CoxR to freebsd-hackers and
  freebsd-current mailing lists that are mainly
  for FreeBSD developers
• Trace users behaviors with webservers log
• Evaluation period Jan/31/2005-Feb/21/2005
• Total users79 (31 unique users)

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Initial knowledge selection

• Unfortunately not all users select knowledge from
  the topic search results
• Maybe they are just try to use CoxR search, or
  search results
• is not good for users
• 18 out of 31 users select initial knowledge
• Type of information selected
• CVS 12
• E-mail 4
• GNATS 2
• Selection times average 4 times per topics (min
  1, max 9)

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Topic community search

• Users actually search topic community
• 12 out of 18
• they used to search related people and knowledge
  within the same subsystem
• Average network traversal 2 times
• People-People 1
• People-Knowledge 8
• Knowledge-Knowledge 13

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Discussions

• Initial knowledge selections
• 56 search results would leads to valuable
  information
• Search by keyword, then search by developer
  names and/or date is a typical search patterns
• Topic community selection
• 67 users who find initial knowledge elements are
  successfully find their own topic community
• They used to trace Knowledge-Knowledge and
  People-Knowledge edge of development network

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Conclusion

• CoxR, a search system for open-source software
  development
• CVS, Email, and GNATS
• Development network, topic community
• Evaluation helped with real developers
• Keywords may have its information costs
• Easy to find important keywords
• Links between similar keywords
• Developer roles
• Easy to find people by their roles
• Reuse topic community found by others
• It can be a suggestion of finding out topic
  community

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• Fin

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CoxR
CoxR (Web Server)
CoxR user
CGI-Main
Data Display Record System
Token compare tool
Lexical analysis tool
CVS Info DB
Fusion info DB
E-mail Info DB
Code DB
CoDS
SPxR
Fusion info Create tool
CVS info Create tool
E-mail info Create tool
DB Create tool
E-mail Archive
CVS Repository
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Example case
Sending a password
Needs improvements
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Searching the repositories
Identify similar code
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Searching similar code
Theres an evidence of improvement, but hard to
understand whats are actually changed
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Searching related information
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Search by revision histories
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Search by development time
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Search by keyword openssh
Combining search results will make it easy to
find what we need
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Search similar information
Files commit at the same time (2001/03/20
020640) and same developer (green)
Actual source code of how to hide the password
packet length is found by CoxR
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Solutions
Search how to fix
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Discussions

• Search similar codeshows actual changes
• Search relative infomation Understanding how
• to fix the
  security hole
• Easy to detect what we need, since any kind of
  information, including keywords, time, developer
  name, code fragment, can be used.
• Easy to understand search results by finding
  relative information easily it helps to grasp
  not only what, but also why this change
  happened.

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Conclusion Remarks

• Implementing CoxR, a search system for both CVS
  revisions and email archives.
• Using actual open-source development data, CoxR
  provides easy and quick way to search useful
  information on software development.
• Broader experimentation
• Improvements on search method (multiple search at
  one time)
• Information scoring (define importance/relation
  level of each information)