1. The Evolution of ANT Build Systems
Shane McIntosh, Bram Adams, Ahmed E. Hassan
Software Analysis and Intelligence Lab (SAIL)
Queen's University
Kingston, Canada

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What is a Build System?

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If source
code is like...

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And our
deliverable
is...

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(1a) Select Features

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(1a) Select Features

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(1b) Select Tools

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(1b) Select Tools

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(2) Construct Deliverables

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(2) Construct Deliverables

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(2) Construct Deliverables

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Our build
system could
be..

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Or...

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Or...

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Or...

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Build systems are complex!
Build system entirely re-implemented!

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Build systems are complex!
Dedicated build maintenance resources

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Research Questions
RQ1) Do source code and ANT build systems
co-evolve?
Initial work suggests make build systems
co-evolve with C source code
RQ2) Does the perceived build-time complexity
evolve?
Intuition suggests so

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Two perspectives for studying
build systems
Build System
Static
(Code Analysis)
Dynamic
(Log Analysis)

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Overview of our approach

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Apache ANT
<project name=”example” default=link”>
<target name=”init”>
<mkdir dir=”build” />
</target>
<target name=”compile” depends=”init”>
<javac destdir=”build” ... includes=”**/*.java” />
<javac desdir=”build” ... includes=”**/*.java” />
</target>
<target name=”link”>
<jar jarfile=”build/example.jar” basedir=”build” />
</target>
</project>

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Apache ANT
<project name=”example” default=link”>
<target name=”init”>
<mkdir dir=”build” />
</target>
<target name=”compile” depends=”init”>
<javac destdir=”build” srcdir=”src” includes=”**/*.java” />
<javac desdir=”build” srcdir=”src2” includes=”**/*.java” />
</target>
<target name=”link”>
<jar jarfile=”build/example.jar” basedir=”build” />
</target>
</project>

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Apache ANT
<project name=”example” default=link”>
<target name=”init”>
<mkdir dir=”build” />
</target>
<target name=”compile” depends=”init”>
<javac destdir=”build” srcdir=”src” includes=”**/*.java” />
<javac desdir=”build” srcdir=”src2” includes=”**/*.java” />
</target>
<target name=”link”>
<jar jarfile=”build/example.jar” basedir=”build” />
</target>
</project>

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UML Editor
176 kSLOC
6 kSBLOC
3%
Studied Projects
Web Container
277 kSLOC
11 kSBLOC
4%
App Server
731 kSLOC
29 kSBLOC
4%
IDE
2.9 MSLOC
200 kSBLOC
6%
Domain
Code Size
Build Size
Relative
Size

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RQ1) Do source code and ANT
build systems co-evolve?

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Build System Metrics (Static)

SBLOC – build system size

Halstead metrics – build system complexity
standardize yi=
yi−

Standardization to preserve
curve characteristics

27. 2701/13/02 05/28/03 10/09/04 02/21/06 07/06/07 11/17/08 04/01/10
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
SBLOC
SLOC
Time
StandardizedValue
Build & Source Change Together

28. 2801/13/02 05/28/03 10/09/04 02/21/06 07/06/07 11/17/08 04/01/10
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
SBLOC
SLOC
Time
StandardizedValue
Build & Source Change Together
ANTLR
Abstraction
Module
RestructuringModule
Restructuring

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01/14/04 08/01/04 02/17/05 09/05/05 03/24/06 10/10/06 04/28/07 11/14/07 06/01/08 12/18/08
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
3
SBLOC (4.x)
SLOC (4.x)
Time
StandardizedValue
Build & Source Change Together

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01/14/04 08/01/04 02/17/05 09/05/05 03/24/06 10/10/06 04/28/07 11/14/07 06/01/08 12/18/08
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5
3
SBLOC (4.x)
SLOC (4.x)
Time
StandardizedValue
Build & Source Change Together
Testsuite
Re-write
JAX-RPC
Restructuring

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RQ1) Do source code and ANT
build systems co-evolve?

Growth and reduction periods in build system
and source code often coincide

Periods where this doesn't happen are often
due to the same development event
Suggests source code and ANT build
systems co-evolve

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RQ2) Does the perceived build-
time complexity evolve?

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Build System Metrics (Dynamic)

Build length – number of targets/tasks
executed

Build depth – maximum recursive depth

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init
compile
link
Length = 3
Dynamic
build.xml

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init
compile
link
init
compile
Depth = 2
Dynamic
build.xml sub/build.xml
Length = 5

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1/13/02 10/9/04 7/6/07 4/1/10
-4
-3
-2
-1
0
1
2
3
4
5
6
Length
Depth
Time
StandardizedValueBuild length slowly increasing

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1/13/02 10/9/04 7/6/07 4/1/10
-4
-3
-2
-1
0
1
2
3
4
5
6
Length
Depth
Time
StandardizedValueBuild length slowly increasing
Libs built
from source

38. 3804/19/01 09/01/02 01/14/04 05/28/05 10/10/06 02/22/08 07/06/09
-1.5
-1
-0.5
0
0.5
1
1.5
2
Time
StandardizedValueBuild length and depth growing

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RQ2) Does the perceived build-
time complexity evolve?

Build length increases over time

Build depth also increases

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Other Findings

Halstead complexity of build system highly
correlated with SBLOC

Eclipse build system growing exponentially
(due to exponential growth in plugins)

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Threats to Validity

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Conclusions

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Questions?