Excessive code complexity
Why is this an issue?
Cyclomatic complexity measures the number of independent execution paths through a piece of code. Complex code is:
Hard to test: More paths mean more test cases needed for full coverage.
Hard to understand: Developers struggle to follow complex logic.
Prone to bugs: Complex code is more likely to contain errors.
Difficult to maintain: Changes risk unintended side effects.
Examples
Example of incorrect code (deeply nested conditions):
public String getDiscount(Account acc) {
if (acc.Type == 'Enterprise') {
if (acc.AnnualRevenue > 1000000) {
if (acc.Years_As_Customer__c > 5) {
return '25%';
} else {
return '15%';
}
} else {
return '10%';
}
} else {
return '0%';
}
}
Example of correct code (simplified with early returns):
public String getDiscount(Account acc) {
if (acc.Type != 'Enterprise') {
return '0%';
}
if (acc.AnnualRevenue <= 1000000) {
return '10%';
}
if (acc.Years_As_Customer__c > 5) {
return '25%';
}
return '15%';
}
How can I fix violations?
Reduce complexity by refactoring.
Break large methods into smaller methods, each with a single purpose.
Split complex conditions into multiple well-named variables.
Use early returns to reduce nesting (the "Arrow anti-pattern").
Use strategy or state patterns instead of complex if/else chains.
When should I disable this rule?
You may dismiss specific violations for methods that inherently require complex logic, such as parsers or state machines, where the complexity is justified and well-documented.
Resources