In this presentation, I continue to add material around identifying and cleaning cruft, including a better way to tie the effort to business value.

1. The Technical Debt Trap
Michael J Norton
@DocOnDev
LeanDog LLC*
*The views expressed are not necessarily the views of LeanDog LLC
(but they could be)

2. Rant.begin

3. What is Technical Debt?

4. What is Technical Debt?
Ward Cunningham
oopsla’92

5. What is Technical Debt?
Ward Cunningham
Shipping first time code is
like going into debt.
oopsla’92

6. What is Technical Debt?
Ward Cunningham
Shipping first time code is
like going into debt.
A little debt speeds
development so long
as it is paid back
promptly with a
rewrite.
oopsla’92

7. What is Technical Debt?
Ward Cunningham
The danger occurs
when the debt is not
repaid.
Every minute spent on not-
quite-right code counts as
interest on that debt.
oopsla’92

8. What is Technical Debt?
Ward Cunningham
The danger occurs
when the debt is not
repaid.
Every minute spent on not-
quite-right code counts as
interest on that debt.
oopsla’92

9. Technical Debt is a Good Idea

10. Technical Debt is a Good Idea
WTF?

11. Technical Debt is a Good Idea
Strategic Design Decision

12. Technical Debt is a Good Idea
Strategic Design Decision
Allow for Rapid Delivery
To Elicit Quick Feedback
And Correct Design

13. Technical Debt is a Metaphor
Here Be Danger

14. Metaphors Rock
We reason by analogy
Can’t keep running
at this pace
Building on a weak foundation
Puts pressure on
It’s raining men our design

15. Metaphors Rock
We reason by analogy
Can’t keep running
at this pace
Building on a weak foundation
Puts pressure on
It’s raining men our design
(hallelujah)

16. Metaphorphosis
When Metaphors go wrong
Prudent

17. Metaphorphosis
When Metaphors go wrong
Return on Investment
Short-Term Fraudulent Credit Card
Inadvertent RecklessScheme
Pyramid Debt
Auto Loan
High Interest in the Third Quadrant
Home Loan Voluntary
Intentional Loan Shark Long-Term
Prudent Student Loan
Pragmatic Leverage Operational

18. Metaphorphosis

19. Metaphorphosis
When Metaphors go wrong
“cut a lot of corners”
James Shore
http://jamesshore.com/Blog/CardMeeting/Voluntary-Technical-Debt.html
“quick and dirty”
Martin Fowler
“sloppy”
http://www.martinfowler.com/bliki/TechnicalDebt.html
David Laribee “just hack it in”
http://msdn.microsoft.com/en-us/magazine/ee819135.aspx
Steve McConnell
http://blogs.construx.com/blogs/stevemcc/archive/2007/11/01/technical-debt-2.aspx

20. Technical Debt Quadrant
http://martinfowler.com/bliki/TechnicalDebtQuadrant.html

21. That’s not what I said
Ward Cunningham
[Many] have explained the debt metaphor
and confused it with the idea that
you could write code poorly with
the intention of doing a good job later.
http://www.youtube.com/watch?v=pqeJFYwnkjE&feature=player_embedded youtube.com 2009

22. That’s not what I said
Ward Cunningham
[Many] have explained the debt metaphor
and confused it with the idea that
you could write code poorly with
the intention of doing a good job later.
http://www.youtube.com/watch?v=pqeJFYwnkjE&feature=player_embedded youtube.com 2009

23. That’s not what I said
Ward Cunningham
... confused it with
the idea that you
could write code
poorly ... youtube.com 2009

24. Clean Code is Required
Ward Cunningham
The ability to pay back debt [...]
depends upon you writing code that
is clean enough to be able to refactor
as you come to understand your
problem. youtube.com 2009

25. Clean Code is Required
Ward Cunningham
The ability to pay back debt [...]
depends upon you writing code that
is clean enough to be able to
refactor as you come to
understand your problem. youtube.com 2009

26. Dirty Code is a Bad Idea
Ward Cunningham
Dirty code is to technical debt as the
pawn broker is to financial debt.
Don't think you are ever going to get
your code back.
http://twitter.com/WardCunningham/status/3742903303 twitter 2009

27. Is it Technical Debt?
Ask yourself...
Is the code clean?
Is the code tested?
Is there a learning objective?
Is there a plan for payback?
Is the business truly informed?

28. Is it Technical Debt?
If you said no to even one
Is the code clean?
Is the code tested?
Is there a learning objective?
Is there a plan for payback?
Is the business truly informed?
Then you don’t have Technical Debt

29. You have a mess
Mess (noun)
1. Disorderly accumulation, heap, or jumble
2. A state of embarrassing confusion
3. An unpleasant or difficult situation

30. You have cruft
Cruft (noun)
1. An unpleasant substance
2. The result of shoddy construction
3. Redundant, old or improperly written code

31. Chill. It’s just semantics, man.

32. Chill. It’s just semantics, man.
JUST Semantics?
Technical Debt is Good

33. Chill. It’s just semantics, man.
JUST Semantics?
Technical Debt is Good

34. Chill. It’s just semantics, man.
JUST Semantics?
Quick and Dirty is Technical Debt is Good

35. Chill. It’s just semantics, man.
JUST Semantics?
Quick and Dirty is Good

36. Chill. It’s just semantics, man.
JUST Semantics?
Quick and Dirty is Good

37. Technical Debt Quadrant

38. Technical Debt Quadrant
“Let’s deploy and
gather more
information.”

39. “Technical Debt”
in Other Industries
Construction
http://www.constructionmanagementschools.net/wp-content/uploads/2010/04/construction-mistakes-18.jpg

40. “Technical Debt”
in Other Industries
Construction
Reckless and Deliberate
http://www.constructionmanagementschools.net/wp-content/uploads/2010/04/construction-mistakes-18.jpg

41. “Technical Debt”
in Other Industries
Automotive
http://blog.ivman.com/wp-content/HomeRepair.jpg

42. “Technical Debt”
in Other Industries
Automotive
Reckless and Deliberate
http://blog.ivman.com/wp-content/HomeRepair.jpg

43. “Technical Debt”
in Other Industries
Medical
http://www.scientificamerican.com/media/inline/blog/Image/MedicalError.jpg

44. “Technical Debt”
in Other Industries
Medical
Reckless and Inadvertent
http://www.scientificamerican.com/media/inline/blog/Image/MedicalError.jpg

45. Technical Debt Quadrant
“Let’s deploy and
gather more
information.”

46. Technical Debt Quadrant
ible “Let’s deploy and
ns gather more
o
sp
information.”
Ir re

47. Technical Debt Quadrant
ible “Let’s deploy and
n s gather more
o
sp
information.”
Ir re
n t
e te
m p
In co

48. Technical Debt Quadrant
le ic al
s ib “Let’s deploy and
n
h t
o n gather more
ec eb
sp
information.”
T
Ir re D
n t
e te
m p
In co

49. Cruft or Debt?
DataSet aDs, qDs;
aDs = _dbConnector.UpdateAgentList();
qDs = _dbConnector.GetQueueList();
foreach (DataTable aTable in aDs.Tables) {
foreach (DataRow aRow in aTable.Rows) {
foreach (DataColumn aColumn in aTable.Columns) {
DataSet asDs = _dbConnector.GetAgentSkills(aRow[aColumn].ToString());//AgentId
foreach (DataTable asTable in asDs.Tables) {
foreach (DataRow asRow in asTable.Rows) {
foreach (DataColumn asColumn in asTable.Columns) {
foreach (DataTable qTable in qDs.Tables) {
foreach (DataRow qRow in qTable.Rows) {
foreach (DataColumn qColumn in qTable.Columns) {
DataSet sqDs = _dbConnector.GetSkillsForQueue(qRow[qColumn].ToString());
foreach (DataTable sqTable in sqDs.Tables) {
foreach (DataRow sqRow in sqTable.Rows) {
foreach (DataColumn sqColumn in sqTable.Columns) {
foreach (string skill in sqRow[sqColumn].ToString().Split(paramDelimStr)) {
if (skill == asRow[asColumn].ToString()) {
try {
_dbConnector.SetAgentQueueSkill(aRow[aColumn].ToString(),
qRow[qColumn].ToString(),
skill);
}
catch { continue; }
}}}}}}}}}}}}}}
http://thedailywtf.com/Series/2010/3/CodeSOD.aspx

50. Cruft or Debt?
DataSet aDs, qDs;
aDs = _dbConnector.UpdateAgentList();
http://thedailywtf.com/Series/2010/3/CodeSOD.aspx

51. Cruft or Debt?
if ((customer.state == “AL” && customer.type ==
CustomerType.GENERAL_AGENT && customer.revenue > 100000)
|| (customer.type == CustomerType.RETRO_AGENT &&
(customer.state == “WI” || customer.state == “IL”))
|| (customer.type == CustomerType.FED_MANAGEMENT &&
customer.revenue > 150000)) { ... }

52. Cruft or Debt?
if (customer.isFederallyRegulated()) { ... }

53. Cruft or Debt?
double getSpeed() {
switch (_type) {
case EUROPEAN:
return getBaseSpeed();
case AFRICAN:
return getBaseSpeed() - getLoadFactor() * _numberOfCoconuts;
case NORWEGIAN_BLUE:
return (_isNailed) ? 0 : getBaseSpeed(_voltage);
}
throw new RuntimeException ("Should be unreachable");
}
http://www.refactoring.com/catalog/replaceConditionalWithPolymorphism.html

54. Cruft or Debt?
class Swallow ...
double getSpeed() { return getBaseSpeed(); }
end class
class EuropeanSwallow ...
end class
class AfricanSwallow ...
double getSpeed() { return super.getSpeed - coconutLoad(); }
double coconutLoad() { return getLoadFactor() * _numberOfCoconuts; }
end class
class NorwegianSwallow ...
double getSpeed() { return (_isNailed) ? 0:getBaseSpeed(_voltage); }
end class

55. Messy Code is a Bad Decision
Every Time

56. Messy Code is a Bad Decision
Every Time
You are a professional developer
(Professionals behave ethically)

57. Messy Code is a Bad Decision
Every Time
You are a professional developer
(Professionals behave ethically)
You are going to create unintentional cruft
(You can’t help it. It’s unintentional.)

58. Messy Code is a Bad Decision
Every Time
You are a professional developer
(Professionals behave ethically)
You are going to create unintentional cruft
(You can’t help it. It’s unintentional.)
You have to clean up the existing cruft
(Intent doesn’t alter Responsibility)

59. Grammy Doesn’t Love Me!
Setting Expectations

60. The Trap
Mess begets mess

61. The Trap
Mess begets mess
Precedent for Speed over Quality
Expectation of increased velocity
Mess slows you down
Must generate more mess to keep up

62. The Trap
Mess begets mess
Precedent for Speed over Quality
Expectation of increased velocity
Mess slows you down
Must generate more mess to keep up
Ask permission to do your job correctly

63. Avoid The Trap
Incremental Fixes Fail
http://www.jacoozi.com/blog/wp-content/uploads/2007/01/refactoring_coc_big.jpg

64. Avoid The Trap
Clean Constantly

65. Avoid The Trap
Clean Constantly
Never make an intentional mess
Monitor your “Technical Debt”
Follow the Boy Scout Rule
Quality is your responsibility

66. Avoid The Trap
Clean Constantly
Never make an intentional mess
Monitor your “Technical Debt”
Follow the Boy Scout Rule
Quality is your responsibility
NEVER ask permission to do your job correctly

67. Monitoring “Technical Debt”
A few key metrics

68. Monitoring “Technical Debt”
A few key metrics
Code Coverage
Cyclomatic Complexity
Coupling
Maintainability

69. Monitoring Cruft/Debt
Code Coverage

70. Monitoring Cruft/Debt
Code Coverage
Code exercised by automated tests
Monitor test types separately
Don’t set a coverage target
100% Coverage is a smell

71. Monitoring Cruft/Debt
Code Coverage
Code exercised by automated tests
Monitor test types separately
Don’t set a coverage target
100% Coverage is a smell
Monitor trends, not points

72. Monitoring Cruft/Debt
Cyclomatic Complexity

73. Monitoring Cruft/Debt
Cyclomatic Complexity
Number of logical branches in code
Direct relationship with bugs
Typically high in concentrated areas
Reduce Conditionals

74. Monitoring Cruft/Debt
Cyclomatic Complexity
Number of logical branches in code
Direct relationship with bugs
Typically high in concentrated areas
Reduce Conditionals
Monitor trends, not points

75. Monitoring Cruft/Debt
Coupling

76. Monitoring Cruft/Debt
Coupling
Interconnectedness of systems
High Coupling = Difficult to Change
Afferent (Toward) and Efferent (Away)
Dependency Injection

77. Monitoring Cruft/Debt
Coupling
Interconnectedness of systems
High Coupling = Difficult to Change
Afferent (Toward) and Efferent (Away)
Dependency Injection
Monitor trends, not points

78. Debt/Cruft Cards
Tie it to Business Value

79. Debt/Cruft Cards
Tie it to Business Value
Velocity
Scalability
Availability

80. Debt/Cruft Cards
Tie it to Business Value
Velocity
Scalability
Availability
Maintainability

81. Review
Technical Debt
Cruft

82. Review
Technical Debt
Is a strategic design decision
Requires the business to be informed
Requires a pay-back plan - (Clean Code)
Cruft

83. Review
Technical Debt
Is a strategic design decision
Requires the business to be informed
Requires a pay-back plan - (Clean Code)
Cruft
Happens
Needs to be monitored and cleaned
Is (probably) NOT Technical Debt

84. Rant.end

85. Thank You!
The Technical Debt Trap
Michael J Norton
@DocOnDev
LeanDog LLC*
doc@leandog.com
*The views expressed are not necessarily the views of LeanDog LLC
(but they could be)