The Impact of Code Review Coverage and Code Review Participation on - PowerPoint PPT Presentation

The Impact of Code Review Coverage and Code Review Participation on Software Quality Shane Yasutaka Bram Ahmed E. McIntosh Kamei Adams Hassan

Code reviews : An opportunity for constructive criticism of code changes Yasu Shane Bram � 2

Code reviews : An opportunity for constructive criticism of code changes + + - Yasu - Patch Shane Bram � 2

Code reviews : An opportunity for constructive criticism of code changes Bram and Yasu, I made a code change. Could you have a look? + Yasu + - - Shane Patch Bram � 2

Code reviews : An opportunity for constructive criticism of code changes Bram and Yasu, I made a code change. Could you have a look? No way, Shane! + Yasu + - - Shane Patch Bram � 2

Code reviews : An opportunity for constructive criticism of code changes Bram and Yasu, I made a code change. Could you have a look? No way, Shane! + Yasu + - - Shane Patch Your code sucks! Bram � 2

Code reviews : An opportunity for constructive criticism of code changes Yasu Shane Bram � 3

Code reviews : An opportunity for constructive criticism of code changes + + - Yasu - Patch Shane Bram � 3

Code reviews : An opportunity for constructive criticism of code changes Bram and Yasu, I made a code change. Could you have a look? Yasu + + Shane - - Patch Bram � 3

Code reviews : An opportunity for constructive criticism of code changes Bram and Yasu, I made a code change. Could you have a look? Watch about NULL values at line 3! Yasu + + Shane - - Patch Bram � 3

Code reviews : An opportunity for constructive criticism of code changes Bram and Yasu, I made a code change. Could you have a look? Watch about NULL values at line 3! Yasu + + Shane - - Patch Your code still sucks! Bram � 3

Traditional � Code Inspections Mandated reviewer checklists and in-person meetings

Traditional � Code Inspections Measurably � improves � software � quality Mandated reviewer checklists and in-person meetings

Traditional � Modern � Code Inspections Code Review Measurably � improves � software � quality Mandated reviewer checklists and in-person Lightweight, tool-supported meetings

Traditional � Modern � Code Inspections Code Review Measurably � improves � ??? software � quality Mandated reviewer checklists and in-person Lightweight, tool-supported meetings

Are properties of the modern code review process linked to software quality? � 5

Are properties of the modern code review process linked to software quality? Coverage � 5

Are properties of the modern code review process linked to software quality? Coverage Participation � 5

Are properties of the modern code review process linked to software quality? � 6

Gerrit Code Review Process + + Yasu + + - - - - Patch Patch Shane Gerrit Bram � 7

Gerrit Code Review Process + Yasu + - + - + Patch - - Shane Gerrit Patch Bram � 7

Gerrit Code Review Process + Yasu + - Request + - + Patch review - - Shane Gerrit Patch Bram � 7

Gerrit Code Review Process Watch about NULL values at line 3! + Yasu + - + - + Patch - - Shane Gerrit Patch Bram � 7

Gerrit Code Review Process Watch about NULL values at line 3! + Yasu + - + - + Patch - - Shane Gerrit Patch Your code sucks! Bram � 7

Gerrit Code Review Process Watch about NULL values at line 3! Yasu + + + + - - - - Shane Gerrit Patch Patch Your code sucks! Bram � 7

Gerrit Code Review Process Yasu Shane Gerrit Bram � 8

Gerrit Code Review Process Yasu Shane Gerrit Bram � 8

Gerrit Code Review Process Upstream Yasu Shane Gerrit Bram � 8

Gerrit Code Review Process Changes are automatically Upstream integrated after review Yasu criteria are satisfied Shane Gerrit Bram � 8

Reviews can be linked to commits in source code repositories commit b5b46f398c1a04ab443bf22ec08c5efbf72c161e Author: Alan Alpert <alan.alpert@nokia.com> Date: Thu Mar 1 20:09:52 2012 +1000 � Add a hidden XandYAxis enum value For Qt 5 XandYAxis is being renamed to XAndYAxis to more consistently follow capitalization rules. Add an undocumented XandYAxis variable to ease porting. Upstream Change-Id: Id9e41dd5578373f5f557937da889a9326ff12e53 Reviewed-by: Martin Jones <martin.jones@jollamobile.com> Gerrit � 9

Reviews can be linked to commits in source code repositories commit b5b46f398c1a04ab443bf22ec08c5efbf72c161e Author: Alan Alpert <alan.alpert@nokia.com> Date: Thu Mar 1 20:09:52 2012 +1000 � Add a hidden XandYAxis enum value For Qt 5 XandYAxis is being renamed to XAndYAxis to more consistently follow capitalization rules. Add an undocumented XandYAxis variable to ease porting. Upstream Change-Id: Id9e41dd5578373f5f557937da889a9326ff12e53 Reviewed-by: Martin Jones <martin.jones@jollamobile.com> Gerrit � 9

Reviews can be linked to commits in source code repositories commit b5b46f398c1a04ab443bf22ec08c5efbf72c161e Author: Alan Alpert <alan.alpert@nokia.com> Date: Thu Mar 1 20:09:52 2012 +1000 � Add a hidden XandYAxis enum value For Qt 5 XandYAxis is being renamed to XAndYAxis to more consistently follow capitalization rules. Add an undocumented XandYAxis variable to ease porting. Upstream Change-Id: Id9e41dd5578373f5f557937da889a9326ff12e53 Reviewed-by: Martin Jones <martin.jones@jollamobile.com> Gerrit � 9

Reviews can be linked to commits in source code repositories commit b5b46f398c1a04ab443bf22ec08c5efbf72c161e Author: Alan Alpert <alan.alpert@nokia.com> Date: Thu Mar 1 20:09:52 2012 +1000 � Add a hidden XandYAxis enum value For Qt 5 XandYAxis is being renamed to XAndYAxis to more consistently follow capitalization rules. Add an undocumented XandYAxis variable to ease porting. Upstream Change-Id: Id9e41dd5578373f5f557937da889a9326ff12e53 Reviewed-by: Martin Jones <martin.jones@jollamobile.com> Gerrit � 9

Are properties of the modern code review process linked to software quality ? � 10

Software Quality as Post-Release Defect Counts Commit types Feature development Defect repairing Merge Upstream Release Development � 11

Software Quality as Post-Release Defect Counts Commit types Feature development Defect repairing Merge Upstream Release Development � 11

Software Quality as Post-Release Defect Counts Commit types Feature development Defect repairing Merge Upstream Release Development � 11

Software Quality as Post-Release Defect Counts Commit types Feature development Defect repairing Merge Upstream Release Development � 11

Software Quality as Post-Release Defect Counts Commit types Feature development Defect repairing Merge Upstream v1.0 Release Development � 11

Software Quality as Post-Release Defect Counts Commit types Feature development Defect repairing Merge Upstream v1.0 Release Development � 11

Software Quality as Post-Release Defect Counts Commit types Feature development Defect repairing Merge Upstream v1.0 Release Development � 11

Defect Models Comp. A How many Comp. B defects? Comp. C � 12

Defect Models 0 Comp. A How many 1 Comp. B defects? 5 Comp. C � 12

Explanatory Defect Models v1.0 Release Development � 13

Explanatory Defect Models Defect model v1.0 Release Development � 13

Explanatory Defect Models Defect model v1.0 � 14

Explanatory Defect Models Analyze relationship between Defect model v1.0 predictors and defects � 14

The Baseline � 15

Product Metrics The Baseline � 15

Product Metrics The Baseline e.g., SLOC, complexity � 15

Product Metrics The Baseline e.g., SLOC, complexity Process Metrics � 15

Product Metrics The Baseline e.g., SLOC, complexity Process Metrics e.g., Prior defects, churn � 15

Product Metrics The Baseline e.g., SLOC, complexity Process Metrics e.g., Prior defects, churn Human Factors Metrics � 15

Product Metrics The Baseline e.g., SLOC, complexity Process Metrics e.g., Prior defects, churn Human Factors Metrics e.g., # Minor contributors � 15

The Context � 16

v5.0.0 The Context 1,339 components 254 defect-prone v5.1.0 1,337 components 187 defect-prone � 16

v5.0.0 The Context 1,339 components 254 defect-prone v5.1.0 1,337 components 187 defect-prone v5.10.0 170 components 15 defect-prone � 16

v5.0.0 The Context 1,339 components 254 defect-prone v5.1.0 1,337 components 187 defect-prone v5.10.0 170 components 15 defect-prone v4.3.0 218 components 24 defect-prone � 16

Are properties of the code reviewing process linked to software quality? Coverage Participation

Are properties of the code reviewing process linked to software quality? Coverage Participation � 18

Are properties of the code reviewing process linked to software quality? Metrics � � Reviewed changes (%) Reviewed churn (%) Coverage Participation � 18