From 9addd626c3026220d3ffddd2e508f9a4b7153bc4 Mon Sep 17 00:00:00 2001
From: Kaarel Raspel <kaarel.raspel@gmail.com>
Date: Thu, 11 Mar 2021 00:00:54 +0200
Subject: [PATCH] Fixes #106

---
 retrieve.go      | 10 +++++++---
 retrieve_test.go |  4 ++++
 utils.go         |  4 ++++
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/retrieve.go b/retrieve.go
index acd7726..d600ba6 100644
--- a/retrieve.go
+++ b/retrieve.go
@@ -9,7 +9,7 @@ import (
 func Get(out interface{}, path string) interface{} {
 	result := get(reflect.ValueOf(out), path)
 
-	if result.Kind() != reflect.Invalid {
+	if result.Kind() != reflect.Invalid && !result.IsZero() {
 		return result.Interface()
 	}
 
@@ -23,7 +23,11 @@ func get(value reflect.Value, path string) reflect.Value {
 		length := value.Len()
 
 		if length == 0 {
-			return resultSlice
+			zeroElement := reflect.Zero(value.Type().Elem())
+			pathValue := get(zeroElement, path)
+			value = reflect.MakeSlice(reflect.SliceOf(pathValue.Type()), 0, 0)
+
+			return value
 		}
 
 		for i := 0; i < length; i++ {
@@ -31,7 +35,7 @@ func get(value reflect.Value, path string) reflect.Value {
 
 			resultValue := get(item, path)
 
-			if resultValue.Kind() == reflect.Invalid {
+			if resultValue.Kind() == reflect.Invalid || resultValue.IsZero() {
 				continue
 			}
 
diff --git a/retrieve_test.go b/retrieve_test.go
index 05a3f22..b773296 100644
--- a/retrieve_test.go
+++ b/retrieve_test.go
@@ -12,6 +12,9 @@ func TestGetSlice(t *testing.T) {
 	is.Equal(Get(SliceOf(foo), "ID"), []int{1})
 	is.Equal(Get(SliceOf(foo), "Bar.Name"), []string{"Test"})
 	is.Equal(Get(SliceOf(foo), "Bar"), []*Bar{bar})
+	is.Equal(Get(([]Foo)(nil), "Bar.Name"), []string{})
+	is.Equal(Get([]Foo{}, "Bar.Name"), []string{})
+	is.Equal(Get([]*Foo{}, "Bar.Name"), []string{})
 }
 
 func TestGetSliceMultiLevel(t *testing.T) {
@@ -33,6 +36,7 @@ func TestGetNil(t *testing.T) {
 
 	is.Equal(Get(foo2, "Bar.Name"), nil)
 	is.Equal(Get([]*Foo{foo, foo2}, "Bar.Name"), []string{"Test"})
+	is.Equal(Get([]*Foo{foo, foo2}, "Bar"), []*Bar{bar})
 }
 
 func TestGetThroughInterface(t *testing.T) {
diff --git a/utils.go b/utils.go
index 2c80a16..43d9a2b 100644
--- a/utils.go
+++ b/utils.go
@@ -77,6 +77,10 @@ func redirectValue(value reflect.Value) reflect.Value {
 			return value
 		}
 
+		if !res.IsValid() && value.Kind() == reflect.Ptr {
+			return reflect.Zero(value.Type().Elem())
+		}
+
 		value = res
 	}
 }