PSS Lab, Paris VII 2009: Orphaned Code: Analyzing Code Left behind and Its Impact on Software Evolution

8/8/2019 PSS Lab, Paris VII 2009: Orphaned Code: Analyzing Code Left behind and Its Impact on Software Evolution

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LibreSoft: General OverviewLibresoft Tools

Introduction to OrphaningApproach

Results and Work in ProgressFurther Work

Bibliography

Orphaned Code: Analysing Code Left behind and

Its Impact on Software Evolution

Daniel Izquierdo Cortazar

[email protected]/Libresoft, Universidad Rey Juan Carlos

PSS Lab, Paris University VIISeptember, 17th 2010

Daniel Izquierdo Cortazar Orphaned Code: Analysing Code Left behind and Its Impact on
http://goforward/http://find/http://goback/


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(cc) 2009 Daniel Izquierdo Cortzar.Some rights reserved. This document is distributed under the Creative

Commons Attribution-ShareAlike 3.0 licence, available inhttp://creativecommons.org/licenses/by-sa/3.0/

Daniel Izquierdo Cortazar Orphaned Code
http://goforward/http://find/http://goback/


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Table of contents

1 LibreSoft: General Overview

2 Libresoft Tools

3 Introduction to Orphaning

4 Approach

5

Results and Work in Progress6 Further Work

7 Bibliography

http://find/http://goback/


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Bibliography

Index


2 Libresoft Tools


4 Approach

5

Results and Work in Progress6 Further Work

7 Bibliography


Lib S f G l O i


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Location

Located at Universidad Rey Juan Carlos, Mstoles, MadridYoungest university in Madrid (12 years old)

Escuela Tecnica Superior de Ingeniera de Telecomunicaciones

GSyC (Grupo de Sistemas y Comunicaciones)

http://libresoft.es


Lib S ft G l O i
http://libresoft.es/http://libresoft.es/http://find/http://goback/


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People

Jess M. Gonzalez-Barahona, head of the group

Gregorio Robles, assistant professor31 people working in Libresoft.

2 professors

20 of them working on projects and research activities

7 of them with LibreSoft internships

2 of them with research (to do PhD) grants


LibreSoft: General Overview


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LibreSoft

Academic activities: mining software repositories.Industrial activities (consultant, mobile networking, web 2.0)

Reports related to libre software, like FLOSSImpact.

Master on Free Software (Galicia and Madrid -

http://master.libresoft.es)


http://master.libresoft.es/http://master.libresoft.es/http://find/http://goback/


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European Projects

QualOSS: Quality of Open Source Software

FLOSSMetrics: Free/Libre/Open Source Software MetricsFLOSSWorld: Free/Libre/Open Source Software: Worldwideimpact study

FLOSSInclude: Free/Libre/Open Source Software,International Cooperation

OSOR: The Open Source Observatory and Repository

QualipSO: Trust and Quality in Open Source Systems




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Empirical Approach: Data Sources

Publicly available data sources

Source Code Management (SCM) (CVS, SVN, Git, Mercurial,Bazaar,...)

Mailing Lists, forum data

Bug Tracking Systems

Web site, wiki, documentation, IRC logs, ...

Other places, FLOSSMole, FLOSSMetrics, ...




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We can directly analyse how a project/community evolvesWe can directly analyse how the developers social network isgrowing

We can measure number of people working on it

...




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Libresoft ToolsIntroduction to Orphaning

ApproachResults and Work in Progress

Further WorkBibliography


Empirical analysis provide a new point of view

Traceability of resultsTraceability of tools

We can not measure how Windows Vista evolved

We can not measure how Microsoft people interact among

themWe can not even measure the size of Windows in number oflines




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Index


2 Libresoft Tools


4 Approach

5 Results and Work in Progress

6 Further Work

7 Bibliography




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Data Sources

CVSAnalY - CVS, SVN, Git.

Mailing List Stats - mbox format

Bicho - SourceForge bug tracking system

SLOCCount (David Wheeler, not from Libresoft)


LibreSoft: General Overviewf


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CVSAnalY: An Example

It extracts statistical information out of CVS, SVN and GitIt transforms that data into a MySQL database

Web site: http://tools.libresoft.es/cvsanaly

Hosted at: http://git.libresoft.es/cvsanaly/

git clone git://git.libresoft.es/cvsanaly


LibreSoft: General OverviewLib f T l
http://tools.libresoft.es/cvsanalyhttp://git.libresoft.es/cvsanaly/http://git//git.libresoft.es/cvsanalyhttp://git//git.libresoft.es/cvsanalyhttp://git.libresoft.es/cvsanaly/http://tools.libresoft.es/cvsanalyhttp://find/http://goback/


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CVSAnalY: CVS Log

[...]1.246 (pj 13-Nov-01): /* Optional arg STRING supplies menu name for the keymap1.246 (pj 13-Nov-01): in case you use it as a menu with x-popup-menu. */)

1.246 (pj 13-Nov-01): (string)1.8 (rms 11-Sep-92): Lisp Object string;1.8 (rms 11-Sep-92): {1.8 (rms 11-Sep-92): Lisp Object tail;1.8 (rms 11-Sep-92): if (!NILP (string))1.8 (rms 11-Sep-92): tail = Fcons (string, Qnil);1.8 (rms 11-Sep-92): else1.8 (rms 11-Sep-92): tail = Qnil;1.1 (jimb 06-May-91): return Fcons (Qkeymap,

1.137 (rms 13-May-97): Fcons (Fmake char table (Qkeymap, Qnil), tail));1.1 (jimb 06-May-91): }

[...]


LibreSoft: General OverviewLib s ft T ls


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CVSAnalY: Basic Metrics

Number of CommitsNumber of Commiters

Committers with highest number of commits

Number of files worked by commiter

etc...




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CVSAnalY: Graphics




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Index


2 Libresoft Tools


4 Approach


6 Further Work

7 Bibliography




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Developer Turnover

Developer turnover is a problem.There is a knowledge gap when senior developers leave aproject

New developers need some time to become familiar with

existing source code




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Knowledge

Tacit knowledge: Not measurable

Explicit knowledge: It remains in the company/projectartifacts, such as code or documentation




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Knowledge Sharing

It is complicated to share tacit knowledge, but ...We can measure explicit knowledge:

Source code management (CVS, SVN, Git, ...)

Mailing lists

Bug tracking systems




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Research Question

How can we measure the knowledge loss due to

developer turnover?

Approach to measure knowledge gap left by developers

Is this knowledge gap a good indicator for the projectshealth?

Useful for managers, to determine risky zones

We can measure the impact in number of lines of codewithout author present in the current team




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Index


2 Libresoft Tools


4 Approach


6 Further Work

7 Bibliography



I d i O h i


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Previous Definitions

Committer: Developer with write access to the SCM system.

Author: Original developer of a line of code

Non-Active Committer: Committer with no activity since agiven date

Orphaned Line: Line of code whose author is a non-activecommitter



I t d ti t O h i


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Studying each period

Monthly analysis

Snapshots from each month



Introduction to Orphaning


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Detection of non-active committers

When does a committer leave the project?

How many lines were authored by her?

new orphaned lines





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Index


2 Libresoft Tools


4 Approach


6 Further Work

7 Bibliography





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Case Studies: GIMPand Evolution

GIMP (GNU Image Manipulation Program) is a graphics

editor





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Evolution combines e-mail, calendar, address book and task

list managements functions





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p gApproach


Bibliography


Both started at the same time (around 1998. At least usingthe Source Code Management system)

Both are included by default in the GNOME desktop (usingthe same process and release cycle)





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p gApproach


Bibliography

Orphaned Lines vs Size

1998-02-28 2000-02-28 2002-03-28 2004-03-28 2006-03-28

Time

0

200000

400000

600000

800000

1000000

1200000

NumberofLines

Ev. Total LinesEv. Orph. Lines

GIMP Total LinesGIMP Orph. Lines

Size an Orp ane Lines Evo ution





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Orphaned Lines Evolution

2001-05-28 2002-09-28 2003-12-28 2005-03-28 2006-06-28 2007-09-28

Time

0

100000

200000

300000

NumberofLines

Evolution 03

GIMP 03Evolution 05GIMP 05Evolution 07GIMP 07

Orp ane Lines Evo ution. Evo ution an GIMP.


LibreSoft: General OverviewLibresoft ToolsIntroduction to Orphaning

A h


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Orphaned Lines Evolution

Three main jumpsCore group of developers turnover is abrupt

Evolution of orphaned lines (not taking into account bigdeletions) is almost stable, just a small decrease

Nowadays, the number of orphaned lines reach the 80%!



A h


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Orphaned Lines GIMP

Just a big jumpCore group of developers remain stable during the wholeproject

Evolution of orphaned lines continuously decrease

Nowadays, the number of orphaned lines reach the 13%!



Approach


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What can tell us Orphaning?

We do not really know...

but we have some intuitions:

Maintenance problems could appear: try to quickly fix adefect in areas which you do not know

Code decay and aging : Orphaned areas in Evolution have not

been modified for a long time



Approach


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Matching Orphaningand Productivity

Work in Progress:

Hypothesis: High orphaning is correlated with lowproductivity



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Approach


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Matching Orphaningand Productivity:GIMP

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Time

0

500

1000

1500

2000

2500

3000

Mod

ifiedFiles

Productivity GIMP Project

6 12 18 24 30 36 42 48 54 60 66 72 78 84 90 96 102

0

100000

200000

300000

400000

500000



Approach


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pp oacResults and Work in Progress


Conclusions

Evolution: New set of developers = Increase of the

productivity (Surprising for us!)

Evolution: Old core group tended to disappear = big jumps inorphaning and productivity

GIMP: Risky situation, if some of the core group developers

disappear



Approach


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ppResults and Work in Progress


Conclusions

Evolution: company-driven project. People have to deal withthat code, they are paid for that job.

GIMP: community-driven project. People just choose, perhapsthey prefer to start from scratch.



Approach


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Index


2 Libresoft Tools


4 Approach


6 Further Work

7 Bibliography



Approach


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Productivity

Detection of files with high levels of orphaningMeasure how they evolve

New Hypothesis: High levels of orphaning (in a file) iscorrelated with low levels of productivity (in that file)



ApproachR l d W k i P


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Enrich the approach

More projects, more data.

Working on Apache 1.3, GTK++, Wireshark and some others.



ApproachR lt d W k i P


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Matching BTS and SCM

New Hypothesis: Modifications in non-authored code maymean the introduction of new bugs (due to the fact you donot really know this area). Thus, higher levels or orphaning,may show higher levels of bug introduction.





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Matching BTS and SCM

New Hypothesis: High levels of orphaning may show lowlevels of knowledge (certifying this by means of directinterviews with libre software developers).





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Index


2 Libresoft Tools


4 Approach


6 Further Work

7 Bibliography





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Bibliography

Slides based on the paper: Using Software Archaeology toMeasure Knowledge Loss in Software Projects due to Developer

Turnover.Daniel Izquierdo-Cortazar, Gregorio Robles, Felipe Ortega and

Jesus M. Gonzalez-Barahona.GSyC/Libresoft, Universidad Rey Juan Carlos (Madrid, Spain).

dizquierdo, grex, jfelipe, [email protected]





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Questions?

Thanks for your attendance!Questions?


Documents

PSS Lab, Paris VII 2009: Orphaned Code: Analyzing Code Left behind and Its Impact on Software Evolution