Connascence - How to detect code smell

Topics covered:
- clean code
- refactoring
- software development

Transcript

1. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connascence 1) Definition 2) Types 3) Examples and Usage
2. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connascence 1) Definition 2) Types 3) Examples and Usage Propose!
3. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com At the outset... DRY BEM Design Patterns Modularity No magic numbers KISS
4. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com
5. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connascence - taxonomy for different types of coupling - software quality metric
6. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Definition
7. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Definition • (1995) Meilir Page-Jones; “In software engineering, two components are connascent if a change in one would require the other to be modified in order to maintain the overall correctness of the system.”
8. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Definition Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name
9. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Definition Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name
10. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Definition Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name Direction where to refactor to
11. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Definition Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name Direction where to refactor to
12. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Definition Three axis of connascence: • Strength: Stronger connascence are harder to discover, or harder to refactor • Degree: An entity that is connascent with thousands of other entities is likely to be a larger issue than one that is connascent with only a few. • Locality: Connascent elements that are close together in a codebase are better than ones that are far apart Strength Weak Strong Degree Few A lot Few A lot Locality Close Far apart
13. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Definition Three axis of connascence: • Strength: Stronger connascence are harder to discover, or harder to refactor • Degree: An entity that is connascent with thousands of other entities is likely to be a larger issue than one that is connascent with only a few. • Locality: Connascent elements that are close together in a codebase are better than ones that are far apart Direction where to refactor to Strength Weak Strong Degree Few A lot Few A lot Locality Close Far apart
14. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Definition Three axis of connascence: • Strength: Stronger connascence are harder to discover, or harder to refactor • Degree: An entity that is connascent with thousands of other entities is likely to be a larger issue than one that is connascent with only a few. • Locality: Connascent elements that are close together in a codebase are better than ones that are far apart Direction where to refactor to Strength Weak Strong Degree Few A lot Few A lot Locality Close Far apart
15. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Types of Connascences: Identity Value Timing Execution Order ----------------- Position Algorithm Meaning Type Name Strength Degree Locality
16. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Types of Connascences: Identity Value Timing Execution Order ----------------- Position Algorithm Meaning Type Name Strength Degree Locality
17. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Types
18. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connassence of Name • Two components must agree on the name of something • Locality close* *same file
19. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connassence of Name • Two components must agree on the name of something • Locality close* *same file
20. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connassence of Name • Two components must agree on the name of something • Locality further apart
21. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connassence of Type • Two components must agree on the type of something
22. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connassence of Type • Two components must agree on the type of something • ...it happens for strong typed languages too:
23. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connassence of Meaning • Two components must agree on the interpretation of a value
24. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connassence of Meaning • Two components must agree on the interpretation of a value Aka. “magical number”
25. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connassence of Position • Two components must be adjacent or occur in a particluar order • 3 degrees of connascence
26. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connassence of Position • Two components must be adjacent or occur in a particluar order
27. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connassence of Algorithm • Two components must agree on a particular algorithm - Encryption, e.g. SHA-2, SHA512, etc - Certificate
28. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connassence of Execution Order • The order of execution of two components is important
29. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connassence of Timing • Two components must agree on the timing of execution E.g. Race condition between threads
30. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connassence of Value • Several values have to change together • Locality further apart
31. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Connassence of Identity • Two components must reference the same entity
32. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Examples
33. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Examples Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name
34. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Examples Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name
35. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Examples Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name
36. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Examples Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name
37. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Examples Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name
38. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Examples Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name
39. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Examples Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name
40. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Examples Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name *still connascence. of value, but locality close
41. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Examples Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name Types of connascence: • Connascence of Identity • Connascence of Value • Connascence of Timing • Connascence of Execution Order • Connascence of Position • Connascence of Algorithm • Connascence of Meaning • Connascence of Type • Connascence of Name
42. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Usage
43. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Usage • Gives me a way to evaluate and prioritize code review/refactor (now I don’t do fixes that are easiest but the most risky) • New tool to communicate (good reviews aren’t based on personal taste but on objective metric) • Gives new developers a framework/compass/guidance for writing good, clean, and maintainable code
44. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Usage • Gives me a way to evaluate and prioritize code review/refactor (now I don’t do fixes that are easiest but the most risky) • New tool to communicate (good reviews aren’t based on personal taste but on objective metric) • Gives new developers a framework/compass/guidance for writing good, clean, and maintainable code Propose!
45. @PandaScriptCom @thadeuszlay linkedin.com/in/trung-thanh-le/ PandaScript.com thanh.le@sinnerschrader.com Sources • “What every Software Developer should know about Object-Oriented Programming” by Meilir Page-Jones • ETE 2012 - Jim Weirich - Connascence Examined: https://www.youtube.com/watch?v=NLT7Qcn_PmI • Codemania 2015: Josh Robb - Connascence & Coupling: https://www.youtube.com/watch?v=Ip2o4vbAK3s