Predicting Defects for Eclipse

Predicting Defects for Eclipse for Eclipse
Thomas Zimmermann • Rahul Premraj • Andreas Zeller
Saarland University

Summary Project Eclipse (eclipse.org) Content Defect counts Complexity metrics Releases 2.0, 2.1, and 3.0 Level Packages and files URL www.st.cs.uni-sb.de/softevo/ More data Eclipse source code

Data Source Bugs Changes

Identifying Fixes
Change history contains ordinary changes as well as bug fixes
Use log messages to discriminate
Search for keywords – e.g. “bug” “fix”
Look out for bug IDs – e.g. “#33547”
Bugs Changes

Mapping Bugs
Each bug report has a unique bug ID
Bug reports contain releases (and sometimes components)
Associate bugs with changes via bug ID
Bugs Changes

Eclipse Bugs

Obtaining Data

Program is open source
Plenty of data available – automatically
Program data – all sorts of code analyses
Process data – changes, bugs, e-mail, etc.
Data set provides bugs, metrics, tokens

Predictions at Work

Eclipse Bug Data <?xml version="1.0" encoding="UTF-8"?>  <defects project="eclipse" release="2.0" dataversion="1.0"> <plug-in name="platform-launcher"> <counts> <count id="pre" value="0" avg="0.0" compilationunits="1" max="0"/> <count id="post" value="0" avg="0.0" compilationunits="1" max="0"/> </counts> <package name="org.eclipse"> <counts> <count id="pre" value="0" avg="0.0" compilationunits="1" max="0"/> <count id="post" value="0" avg="0.0" compilationunits="1" max="0"/> </counts> <package name="org.eclipse.core"> <counts> <count id="pre" value="0" avg="0.0" compilationunits="1" max="0"/> <count id="post" value="0" avg="0.0" compilationunits="1" max="0"/> </counts> <package name="org.eclipse.core.launcher"> <counts> <count id="pre" value="0" avg="0.0" compilationunits="1" max="0"/> <count id="post" value="0" avg="0.0" compilationunits="1" max="0"/> </counts> <compilationunit dir="/platform-launcher/library/" base="Main.java"> <counts> <count id="pre" value="0"/> <count id="post" value="0"/> </counts> </compilationunit> </package> </package> </package> </plug-in>

Eclipse Bug Data
For three Eclipse releases:
For all Eclipse components:
Defect counts before and after release
Complexity metrics
Syntactic tokens
Download at http://www.st.cs.uni-sb.de/softevo/
<?xml version="1.0" encoding="UTF-8"?>  <defects project="eclipse" release="2.0" dataversion="1.0"> <plug-in name="platform-launcher"> <counts> <count id="pre" value="0" avg="0.0" compilationunits="1" max="0"/> <count id="post" value="0" avg="0.0" compilationunits="1" max="0"/> </counts> <package name="org.eclipse"> <counts> <count id="pre" value="0" avg="0.0" compilationunits="1" max="0"/> <count id="post" value="0" avg="0.0" compilationunits="1" max="0"/> </counts> <package name="org.eclipse.core"> <counts> <count id="pre" value="0" avg="0.0" compilationunits="1" max="0"/> <count id="post" value="0" avg="0.0" compilationunits="1" max="0"/> </counts> <package name="org.eclipse.core.launcher"> <counts> <count id="pre" value="0" avg="0.0" compilationunits="1" max="0"/> <count id="post" value="0" avg="0.0" compilationunits="1" max="0"/> </counts> <compilationunit dir="/platform-launcher/library/" base="Main.java"> <counts> <count id="pre" value="0"/> <count id="post" value="0"/> </counts> </compilationunit> </package> </package> </package> </plug-in>

Eclipse Bugs

Where do bugs come from?

Is it the Developers? Does experience matter? Bug density correlates with experience!

How about Testing? Does code coverage predict bug density? Yes – the more tests, the more bugs!

History? I found lots of bugs here. Will there be more? Yes!

How about Metrics? Do code metrics predict bug density? Yes! (but only with history)

Syntactic Tokens? Which tokens predict bug density? imports • extends • implements

Eclipse Imports import org.eclipse.jdt.internal.compiler.lookup.*; import org.eclipse.jdt.internal.compiler.*; import org.eclipse.jdt.internal.compiler.ast.*; import org.eclipse.jdt.internal.compiler.util.*; ... import org.eclipse.pde.core.*; import org.eclipse.jface.wizard.*; import org.eclipse.ui.*; 14% of all components importing ui show a post-release defect 71% of all components importing compiler show a post-release defect Joint work with Adrian Schröter • Tom Zimmermann

Eclipse Imports Correlation with failure Correlation with success import org.eclipse.jdt.internal.compiler.lookup.*; import org.eclipse.jdt.internal.compiler.*; import org.eclipse.jdt.internal.compiler.ast.*; import org.eclipse.jdt.internal.compiler.util.*; ... import org.eclipse.pde.core.*; import org.eclipse.jface.wizard.*; import org.eclipse.ui.*;

What makes code buggy in the first place?

Eclipse Bug Data
For three Eclipse releases:
For all Eclipse components:
Defect counts before and after release
Complexity metrics
Syntactic tokens
Download at http://www.st.cs.uni-sb.de/softevo/
<?xml version="1.0" encoding="UTF-8"?>  <defects project="eclipse" release="2.0" dataversion="1.0"> <plug-in name="platform-launcher"> <counts> <count id="pre" value="0" avg="0.0" compilationunits="1" max="0"/> <count id="post" value="0" avg="0.0" compilationunits="1" max="0"/> </counts> <package name="org.eclipse"> <counts> <count id="pre" value="0" avg="0.0" compilationunits="1" max="0"/> <count id="post" value="0" avg="0.0" compilationunits="1" max="0"/> </counts> <package name="org.eclipse.core"> <counts> <count id="pre" value="0" avg="0.0" compilationunits="1" max="0"/> <count id="post" value="0" avg="0.0" compilationunits="1" max="0"/> </counts> <package name="org.eclipse.core.launcher"> <counts> <count id="pre" value="0" avg="0.0" compilationunits="1" max="0"/> <count id="post" value="0" avg="0.0" compilationunits="1" max="0"/> </counts> <compilationunit dir="/platform-launcher/library/" base="Main.java"> <counts> <count id="pre" value="0"/> <count id="post" value="0"/> </counts> </compilationunit> </package> </package> </package> </plug-in>

Predicting Defects for Eclipse

by promise07 on May 20, 2007

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Predicting Defects for Eclipse — Presentation Transcript