Through the Looking Glass Applying Analytics to Development Michael - - PowerPoint PPT Presentation

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Through the Looking Glass Applying Analytics to Development Michael - - PowerPoint PPT Presentation

Jan 28, 2024 312 likes •1.21k views

Through the Looking Glass Applying Analytics to Development Michael Feathers Independent Consultant Wednesday, November 7, 2012 How Much Do We Know? Wednesday, November 7, 2012 Wednesday, November 7, 2012 Wednesday, November 7, 2012

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SLIDE 1

“Through the Looking Glass”

Applying Analytics to Development

Michael Feathers

Independent Consultant

Wednesday, November 7, 2012

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SLIDE 2

How Much Do We Know?

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SLIDE 3

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SLIDE 4

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SLIDE 5

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SLIDE 6

Rationalistic Bias

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SLIDE 7

Version Control History

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SLIDE 8

Source Control Change Events as Data

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SLIDE 9

Git

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SLIDE 10

Git

Commit

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SLIDE 11

Git

Commit

commit hash (sha1) time/date stamp committer files actual change

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SLIDE 12

Git

Commit

commit hash (sha1) time/date stamp committer files actual change commit hash (sha1) time/date stamp committer method name method body add/change/delete

Method Event

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SLIDE 13

The Open/Closed Principle

"software entities (classes, modules, functions, etc.) should be open for extension, but closed for modification"

  • Bertrand Meyer

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SLIDE 14

100 200 300 400 files

Clojure

# of commits

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SLIDE 15

75 150 225 300 files

Fitnesse

# of commits

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SLIDE 16

17.5 35.0 52.5 70.0 files

JUnit

# of commits

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SLIDE 17

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SLIDE 18

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SLIDE 19

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SLIDE 20

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SLIDE 21

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7.5 15.0 22.5 30.0 time

A Method Lifeline

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SLIDE 23

1 2 3 4 time

Another Method

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SLIDE 24

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SLIDE 26

http://www.physorg.com/news/2011-04-early-lunch.html

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SLIDE 27

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SLIDE 28

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SLIDE 29

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SLIDE 30

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SLIDE 31

Commits per minute of each hour

repo.commits.map {|_,d| d.min }.freq

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SLIDE 32

repo.commits.map {|c,_| repo.commit(c).added_complexity.to_i }

Added Complexity Over Time

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SLIDE 33

Amount of Complexity Added by Hour of Day

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SLIDE 34

Normalized by Commits

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SLIDE 35

A Lifeline

repo.methods.select {|m| m.full_name == "FeelingsController#create" }.first.life_line

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SLIDE 36

Number of Files Touched Per Commit

repo.events.group_by(&:commit).map { |sha, events| events.map(&:file_name).uniq.count }.freq

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SLIDE 37

The Trending View

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SLIDE 38

Methods Ascending

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SLIDE 39

Trending Methods

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SLIDE 40

Static Views

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Classes By Closure Date

[["DummiesController", 2008-04-21 13:03:08 -0700], ["Core::ActiveRecord::AttributeDefaults::ClassMethods", 2008-04-22 16:02:54 -0700], ["Legacy::Database", 2008-04-24 15:37:51 -0700], ["Core::ActiveRecord::AttributeDelegation::ClassMethods", 2008-04-24 20:46:58 -0700], ["Core::ActiveRecord::SkipValidationForHasOnes", 2008-04-29 21:54:32 -0700]]

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SLIDE 42

Classes By Closure Date

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Temporal Correlation of Class Changes

[[["App", "Inventory"], 277], [["Inventory", "Object"], 216], [["Admin", "Inventory"], 195], [["Inventory", "User"], 188], [["Inventory", "Users"], 171], [["Inventory", "Deals"], 167], [["App", "Object"], 159], [["App", "InventoryController"], 152], [["Inventory", "Order"], 149], [["User", "Users"], 149], [["App", "User"], 143], [["Inventory", "InventoryController"], 143], [["Api", "Inventory"], 141], [["Admin", "App"], 136], [["Campaign", "Orders"], 134]]

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Temporal Correlation of Class Changes

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Temporal Correlation of Class Changes

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Enki - A Rails Blogging Platform

5 Unique Committers ["Xavier", "Jason", "Zach", "Pedro", "Gaelian"] 637 method events Spec to method ratios by committer: [0.09245283018867924, "Xavier"], [0.05084745762711865, "Jason"], [0.0, "Zach"], [0.6666666666666666, "Pedro"], [0.0, "Gaelian"]] Number of Method Modifications: Zach => 6 Xavier=> 167 Jason => 10 Pedro => 1

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Enki - CommentController Class

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Enki - Post Class

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Enki - Ownership Effect

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Enki - Average Lines Per Commit By Month

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Enki - Spec Lifelines

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Enki - Hour Profile

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MercuryApp

5 Unique Committers ["Sarah", "coreyhaines", "Cory", "Spencer", "sarah"] 7788 method events Spec to method ratios by committer: [0.40381791483113066, "Sarah"], [0.5220038748962081, "coreyhaines"], [0.0, "Cory"], [0.0, "Spencer"], [0.5171062009978618, "sarah"] Number of Method Modifications: Cory => 629 Sarah=> 739 Spencer => 2

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MercuryApp - User Class

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MercuryApp - FeelingsController Class

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MercuryApp - Ownership Effect

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MercuryApp - Average Lines Per Commit By Month

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MercuryApp - Hour Profile

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SLIDE 59

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Frequency of Inter-commit Intervals

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Frequency of Inter-commit Intervals

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Frequency of Inter-commit Intervals Rhythm

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Frequency of Inter-commit Intervals

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Average Lines of Code Per Commit By Week

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Complexity Tolerance (Developer A)

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Complexity Tolerance (Developer B)

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Ownership Effect (all methods)

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Code Mining Issues

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The Commit Problem

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The Social Environment Problem

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Blame

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Dangerous Knowledge

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Best Practice may be ‘Per Product Analysis’

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Metrics

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“Laws” of Metrics

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“Laws” of Metrics

  • 1. Distance Causes Misunderstanding

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SLIDE 77

“Laws” of Metrics

  • 1. Distance Causes Misunderstanding
  • 2. Highlighting Leads to Focus

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SLIDE 78

“Laws” of Metrics

  • 1. Distance Causes Misunderstanding
  • 2. Highlighting Leads to Focus
  • 3. Focus Leads to Action

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SLIDE 79

“Laws” of Metrics

  • 1. Distance Causes Misunderstanding
  • 2. Highlighting Leads to Focus
  • 3. Focus Leads to Action
  • 4. Focus Leads to Side-Effects

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SLIDE 80

“Laws” of Metrics

  • 1. Distance Causes Misunderstanding
  • 2. Highlighting Leads to Focus
  • 3. Focus Leads to Action
  • 4. Focus Leads to Side-Effects
  • 5. Knowledge Defines Normality

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Things to Look For

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Things to Look For

  • Relationship between the presence of tests and

refactoring

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Things to Look For

  • Reasons behind high churn in classes and methods

(beyond the runaways)

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Things to Look For

  • Identification Patterns for Good Programming Episodes

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Future Work

  • Automated commits for full picture of development

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Future Work

  • Analysis of changes for developer improvement

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Future Work

  • Catalog of norms for good development

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Future Work

  • Integration with bug fix data

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