1.
Brutal Refactoring
Lying Code
The Churn
(and other emotional stories from)
Legacy Land!

2.
The big questions
What can I know?

3.
The big questions
What should I do?

4.
The big questions
What may I hope?

5.
( °□°╯ ）╯︵ ┻━┻

6.
(Maintaining) legacy code is depressing

7.
“Technical debt”

8.
“Continuous
improvement”

9.
What can I know?

10.
When using PHP: not much

11.
Dynamic types
/**
* @return mixed
*/

12.
No compiler
if (!'a') {
// ...
}

13.
No compiler
$a = 'a';
if ($a === 'a') {
// ...
}

14.
No compiler
if (!$a === false) {
// ...
}

15.
No compiler
if (false === !$a) {
// ...
}

16.
Domain knowledge has left the building
if ($product->isGrewBilly() && $customer->prefersPayTotum()) {
$this->emailManager->sendTotumBillyAnnuitySummary();
}

17.
"Legacy code is code without an owner"

18.
So... what should I do?

19.
Read books

20.
Replace a constructor argument
Override a method
Tamper with the class loader
Use AOP
...

21.
The
Churn.

22.
Core domain concepts

23.
Scaring away Churn monsters is a lot of
work too!

24.
Guess: who are the monsters in your
project?

25.
What else... should I do?

26.
Little things?

27.
Weed the ground

28.
Pick up the stones, then put them back

29.
Look your monster in the eyes

30.
“Could this go somewhere else?”

31.
What may I hope?

32.
How did we get here?

33.
Different developers
Changing landscape
Bad management
Bad developers

34.
You know what to do...
●
Write tests from the start
●
Document code and architecture decisions
●
Agree on a coding style
●
Enforce a coding standard
●
Run static analysis tools
And so on...

35.
You can hope that people will do this from
now on (actually, force them...)

36.
The secret: most code could remain
untouched

37.
Change will be needed, where?

38.
The framework
(yes, you will switch frameworks some day!)

39.
What can you do to make it
easier?
Don't use everything from the framework

40.
What can you do to make it
easier?
Rely on your own interfaces and
implementations

41.
Consolidate

42.
Not everything needs “consolidation”

43.
What can you do to make it
easier?
Don't let the framework leak into the core

44.
Again … What may I hope?

45.
Naive?

46.
This is it

47.
Do what you can do

48.
“Burnout”

49.
This is it

50.
How to make huge improvements to a
project?

51.
The big rewrite?

52.
Make the change easy,
then make the easy change

53.
Just Do It!

54.
Always keep the project in a working state