Mocks for interfaces which return named nillable types do not have nil checks

[spaowi]

Example:

package main
type B interface {
  Bar()
}
type A interface {
  Get() B
}

Running mockery -name A -print on this does not yield a mock which checks for nil! The problem is that the B return type is parsed to an *ast.Ident, not an *ast.InterfaceType (and therefore isNillable returns false).

You can use the type of the identifier to handle this case, e.g.:

func (g *Generator) isNillable(typ ast.Expr) bool {
        switch t := typ.(type) {
        case *ast.StarExpr, *ast.ArrayType, *ast.MapType, *ast.InterfaceType, *ast.FuncType, *ast.ChanType:
                return true
        case *ast.Ident:
                switch d := t.Obj.Decl.(type) {
                case *ast.TypeSpec:
                        switch d.Type.(type) {
                        case *ast.StarExpr, *ast.ArrayType, *ast.MapType, *ast.InterfaceType, *ast.FuncType, *ast.ChanType:
                                return true
                        }
                }
        }
        return false
}

[dakiva]

@spaowi Your example works for the case where the interface return type is in the same package as the interface being mocked. However, when the interface is an exported type, the returned interface is incorrectly parsed as a *ast.SelectorExpr. With the code above, generating a mock for bar.A will not yield a mock that checks for nil:

package foo

type B interface {
MyFunc()
}

package bar

import "foo"

type A interface {
Get() foo.B
}

[spaowi]

Good point. I assume handling that case will require parsing imported packages.

[evanphx]

There is another feature that requires parsing other imported packages, so perhaps mockery should parse them to pull in other interfaces...