Architectural reconstruction (3): Evolution Analysis

Question 1

What is Lehman’s Law of Continuing change about?

Answer 1

An e-type program that is used in a real-world environment must change, or become
progressively less useful in that environment. (Lehman’s Law of Continuing Change).

E-type system:
- An e-type system is embedded in the real world
- The world changes, so the system must change

Question 2

What is Software Evolution?

Answer 2

Software evolution is the continual development of a piece of software
after its initial release to address changing stakeholder and/or market
requirements.
- We used to talk about software maintenance
- Nowadays evolution is the preferred term

Question 3

What is Evolution Analysis, and how to we find information about its evolution?

Answer 3

= the study of how a system evolves over time.
Where can we find such information about its evolution?
- Version control repository.
- E.g. use the tool Git-Truck

Question 4

What can Git Truck be used for in architecture recovery?

Answer 4

To highlight the parts of the system that are most changed.
Studies observe correlation between code churn and complexity metrics.
High code churn predicts bugs better than size.

Question 5

What is code churn?

Answer 5

= a metric that indicates how often a given piece of code—e.g., a file, a class, a
function—gets edited.
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EXTRA: can be detected with language independent analysis (which is good for
polyglot systems)

Question 6

What is evolutionary hotspot viewpoint?

Answer 6

These hotspots are areas where the system’s architecture needs to be flexible and adaptable to accommodate future evolution and growth.
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the focus is on identifying and analyzing those specific parts of the system that are likely to undergo frequent changes or have a higher potential for future modifications