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An Empirical Study of the Copy and Paste Behavior during Development

Tarek M. Ahmed Weiyi Shang Ahmed E. Hassan

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Copy & Paste leads to clones

//Code fragment Copy

//Code fragment

Paste

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//Code fragment Copy

//Code fragment

Paste

Copy & Paste leads to clones

Large number of code clones

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Clone detection tools detect C&P after it is performed

Source Code

Clone Detection

C&P

C&P

Code Clones

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There exists no large scale C&P study on developers

Controlled ExperimentSmall number Experienced only

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Larger scale study exists on regular users

• Regular computer users• Non-Software development tasks

A large scale C&P study is needed for software development tasks

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Eclipse Usage Data Collector (UDC) enables a large scale C&P study

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Months>1 Millions

Users

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How to detect C&P in Eclipse UDC

User ID What Kind … Description

104526 Executed Command org.eclipse.ui.edit.copy

User performs Copy

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How to detect C&P in Eclipse UDC

User ID What Kind … Description

104526 Executed Command org.eclipse.ui.edit.copy

104526 Executed Command org.eclipse.ui.edit.paste

User performs Paste

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Our study focuses on users who frequently and actively use Eclipse

Create Development

Sessions

Find Active Sessions

Find Frequent Users

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20

Months4 Million C&P

20,000

Users

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Uncovering the C&P behavior of IDE users

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Average number of C&P per hour isdifferent from recent studies

2.73 16

Our finding Previous finding

#Commands > Average #Commands + 1 Standard deviation

#Commands > Average #Commands + 2 Standard deviation

Heavy Editing

Sessions

V. Heavy Editing

Sessions

11.39 13.18

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Do IDE users follow the same C&P patterns as regular users?

How do IDE users copy and paste code across different file formats?

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Do IDE users follow the same C&P patterns as regular users?

How do IDE users copy and paste code across different file formats?

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Copy

//Code fragment

Paste

//Code fragment

Inside the same file Between different files

Copy

//Code fragment

//Code fragment

Paste

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Copy

//Code fragment

Paste

//Code fragment

Inside the same file Between different files

Copy

//Code fragment

//Code fragment

Paste

IDE users often C&P within the same file

80%IDE 20%

IDE23%

Regular 77%Regular

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IDE users perform consecutive C&P

A

Repeat

Copy

C Copy

B Paste

D Paste

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IDE users perform consecutive C&P

AB

C

Distribution

Copy

Paste

Paste

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IDE users perform consecutive C&P

A B C

Relay

Copy

Copy Paste

Paste

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IDE users often perform relay on C&P

A

C

B

DA

B

C

A B C

Repeat Distribution

Relay

32%Regular

9%IDE

36%Regular

1%IDE

2%Regular

33%IDE

Others

30%Regular

57%IDE

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C&P behavior of IDE users is different from regular users

IDE Users

Higher Within Higher Relay Lower Distribution

Regular Users

Higher Between Lower Relay Higher Distribution

Eclipse IDE requires tailored C&P support tools that differfrom regular users’ C&P tools

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Do IDE users follow the same C&P patterns as regular users?

How do IDE users copy and paste code across different file formats?

There are major differences between C&P behavior of Eclipse IDE users and C&P behavior of regular users.

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Do IDE users follow the same C&P patterns as regular users?

How do IDE users copy and paste code across different file formats?

There are major differences between C&P behavior of Eclipse IDE users and C&P behavior of regular users.

There exists large number of C&P between editors, hence, clone detection techniques would consider detect clones across different languages.

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Summary

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