recommending refactorings based on team co-maintenance patterns

04/09/2023

Recommending Refactorings based on Team Co-

Maintenance Patterns

Gabriele Sebastiano Nikolaos Massimiliano Rocco Gerardo

Bavota Panichella Tsantalis Di Penta Oliveto Canfora

04/09/2023

Outline

Context and Motivations- Software Development- Team based Refactoring (TBR) for restructuring

source code

Case Study- User Study: releases of the Android APIs

Results- Evaluation of TBR and comparison with the state of the art

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Refactoring is…

‘‘…a disciplined technique for restructuring an existing body of code, altering its internal structure without changing its external behavior’’. [Fowler 1999]

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Refactoring Sources of Information

- Refactoring operation need to capturing relation between code components.

- Various are the explored sources of information:

- Structural (Static and Dynamic);

- Semantic;

- Historical.

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Structural Information

- calls between methods, shared attributes, call relationships occurring during program execution.

Pros: - precise

information;- easy to capture;- always available.Cons:- may be imprecise;- may miss some kinds of dependencies.

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Semantic Information

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Semantic Information

- Textual similarity between code components.

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Semantic Information

Pros: - easy to capture;- always available.Cons:- Assumption that

terms are consistently used in the code

- Textual similarity between code components.

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Historical Information

Fabio Palomba et al. in ‘’Detecting bad smells in source code using change history information.’’’  - ASE 2013.

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Historical Information

Fabio Palomba et al. in ‘’Detecting bad smells in source code using change history information.’’’  - ASE 2013.

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Historical Information

Fabio Palomba et al. in ‘’Detecting bad smells in source code using change history information.’’’  - ASE 2013.

Pros: - precise information.Cons:- too strong to capture.

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Are we Missing other Kinds of Dependencies?

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Software development is a very human intensive activity….

Are we Missing other Kinds of Dependencies?

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Social Dimension

Time interval considered

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Social Dimension

Time interval considered

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Team-based Refactoring Opportunity

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Extract Class

Team-based Refactoring Opportunity

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Our ContributionTeam Based Refactoring (TBR):Information derived from teams to identify refactoring opportunities.

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Our Contribution

1) Teams identification

2) Detection of Refactoring opportunities (e.g. extract class refactoring)

Team Based Refactoring (TBR):Information derived from teams to identify refactoring opportunities.

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Teams Identification

Time

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Teams Identification

Time

Time window considered

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Teams Identification

Time

Time window considered

Class 1

Class 3

Class 2

Class 4

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Teams Identification

Time

Time window considered

Class 1

Class 3

Class 2

Class 4

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Teams Identification

Time

Time window considered

Class 1

Class 3

Class 2

Class 4

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Teams Identification

Time

Time window considered

Class 1

Class 3

Class 2

Class 4

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Teams Identification

Time

Time window considered

Class 1

Class 3

Class 2

Class 4

Ward's hierarchical clustering

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Detection of Refactoring Opportunities

Time window considered

1) Existence of a set of methods owned by a Team

Class 1

Class 3

Class 2

Class 4

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Detection of Refactoring Opportunities

Time window considered

1) Existence of a set of methods owned by a Team

2) Splitting classes with many responsabilities

Class 1

Class 2

Class 4Class 3

Class 2 –a)

Class 2 –b)

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Detection of Refactoring Opportunities

Time window considered

1) Existence of a set of methods owned by a Team

2) Splitting classes with many responsabilities

Class 2 –a)

Class 2 –b)

Class 1

Class 3

Class 2

Class 4

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Case Study

Goal: evaluate and compare the quality of the refactoring solutions identified by TBR with approaches based on more traditional sources.

Research questions:

• RQ1: Is the information derived from teams useful to identify refactoring opportunities?

• RQ2: Is the information derived from teams complementary to the sources of information typically exploited to identify refactoring opportunities?

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Context

•Objects:

•Subjects:

2 PhD students1 Industrial developer

Project from Andr. Api Period KLOC

framework-opt-telephony

Aug 2011-Jan 2013 73-78

framework-base Oct 2008-Jan 2013 534-1,043

framework-support Feb 2011-Nov 2012 58-61

sdk Oct 2008-Jan 2013 14-82

tool-base Nov 2012-Jan 2013 80-134

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RQ1: Is the information derived from teams

useful to identify refactoring opportunities?

Medium/Low perceived effort

Useful Refactoring solutions

78%

74%

22%

26%

NO YES

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RQ1: Is the information derived from teams

useful to identify refactoring opportunities?

Medium/Low perceived effort

Useful Refactoring solutions

78%

74%

22%

26%

NO YES

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RQ1: Is the information derived from teams

useful to identify refactoring opportunities?

Medium/Low perceived effort

Useful Refactoring solutions

78%

74%

22%

26%

NO YES

RQ2: TBR complementarity with other sources typically used for identifying refactoring

opportunities

Evaluation: MoJoFM

RQ2: TBR complementarity with other sources typically used for identifying refactoring

opportunities

Evaluation: MoJoFM

C1 C2

1

2 34

1

2 54

6

MoJoFM = 0 move + 0 join = 0= 1= 21 move 2 move

3

6

5

RQ2: TBR complementarity with other sources typically used for identifying refactoring

opportunities

Evaluation: MoJoFM

C1 C2

1

24

1

2 54

MoJoFM = 2 move + 0 join = 2= 3= 41 join2 join

63

3

6

5

3 move = 5

5

RQ2: TBR complementarity with other sources typically used for identifying refactoring

opportunities

Evaluation: MoJoFM

C1 C2

1

24

1

2 54

MoJoFM = 3 move + 3 join = 5= 63 join

3

6

5

63

max(∀ mno(Ci,Cj)max(∀ mno(Ci,Cj)

Structural U Semantic U Historical

Structural Semantic Historical0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

70%

30%

43%35%

RQ2: TBR complementarity with other sources typically used for identifying refactoring

opportunities

Structural U Semantic U Historical

Structural Semantic Historical0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

70%

30%

43%35%

30%

RQ2: TBR complementarity with other sources typically used for identifying refactoring

opportunities

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Conclusion

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Conclusion

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Conclusion

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Conclusion

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Conclusion