LowFile-scopeRuby Plug & play

Extract duplicated business logic to models

Move domain behavior from controllers/views into models or service objects.

Why this matters

Improves cohesion, reuse, and testability.

Side-by-side examples engineers can pattern-match during review.

Avoid

def create; total = params[:items].sum { |i| i[:p]*i[:q] }; ... end

Prefer

def create; total = OrderCalculator.total(params[:items]); ... end

Bad

controller computes totals

Good

service/model encapsulates logic

From the same buckets as this rule.

Critical
Avoid Duplicating String Literals
Store repeated string literals in constants or variables to improve maintainability and reduce redundancy.
duplication-complexitymaintainability
Critical
Avoid Redundant `None` Comparisons
Identify cases where `x is None` or `x is not None` is used redundantly when `x` is always or never `None`. This may indicate a deeper logic issue.
duplication-complexityreadability-refactor+1
High
Avoid Functions That Always Return the Same Value
Identify functions that return the same value regardless of input. This may indicate poor design or a logic error.
duplication-complexityreadability-refactor+1