verify-functions.md

Verify Functions

Functions can be validated for their signatures, modifiers, naming patterns, return types, and parameter structures.

To verify functions start by querying all functions present in the project:

Konsist
.scopeFromProject()
.functions()
...

In practical scenarios you'll typically want to verify a specific subset of functions - such as those defined inside classes:

Konsist
.scopeFromProject()
.classes()
.functions()
...

Konsist API allows to query local functions:

Konsist
.scopeFromProject()
.classes()
.functions(includeLocal = true)
...

Konsist allows you to verify multiple aspects of a functions. For a complete understanding of the available APIs, refer to the language reference documentation for KoFunctionDeclaration.

Let's look at few examples.

Verify Name

Function names can be validated to ensure they follow project naming conventions and patterns.

Check if function name starts with get :

...
.assertTrue {
   it.hasNameStartingWith("get")
}

Verify Modifiers

Function modifiers can be validated to ensure proper encapsulation and access control.

Check if function has public or default (also public) modifier:

..
.assertTrue {
   it.hasPublicOrDefaultModifier
}

Verify Annotations

Function-level and member annotations can be verified for presence, correct usage, and required attribute values.

Check if function is annotated with Binding annotation:

...
.assertTrue {
   it.hasAnnotationOf(Binding::class)
}

Verify Body Type

Functions with block bodies (using curly braces) can be validated to ensure compliance with code structure requirements:

...
.assertTrue { 
    it.hasBlockBody 
}

Expression body functions (using single-expression syntax) can be verified to maintain consistent style across the codebase:

...
.assertTrue { 
    it.hasExpressionBody 
}

Verify Parameters

Function parameters can be validated for their types, names, modifiers, and annotations to ensure consistent parameter usage.

Check if function has parameter of type String:

...
.assertTrue { 
    it.hasParameter { parameter  -> parameter.hasTypeOf(String::class) }
}

Verify Return Type

Return types can be checked to ensure functions follow expected return type patterns and contracts.

Check if function has Kotlin collection type:

...
.assertTrue { 
    it.returnType?.sourceDeclaration?.isKotlinCollectionType
}

Verify Generic Parameters

Generic type parameters can be validated to ensure proper generic type usage and constraints.

Check if function has type parameters:

...
.assertTrue { 
    it.hasTypeParameters()
}

Verify Generic Type Arguments

Generic type arguments can be checked for correct usage.

Check if return type has no type arguments:

...
.assertFalse {
    it.returnType?.hasTypeArguments()
}

Verify Top Level

Top-level functions (functions not declared inside a class) can be specifically queried and validated:

...
.assertTrue { 
    it.isTopLevel
}

This helps ensure top-level functions follow project conventions, such as limiting their usage or enforcing specific naming patterns.