Fix Get() panic on nil pointers. Fixes #396.

Author: knadh

koanf.go

@@ -351,6 +351,13 @@ func (ko *Koanf) Get(path string) any {
 		return v
 	case map[string]any:
 		return maps.Copy(v)
+	case nil:
+		return nil
+	}
+
+	// Skil nil pointers before copying.
+	if rv := reflect.ValueOf(res); rv.Kind() == reflect.Ptr && rv.IsNil() {
+		return nil
 	}
 
 	out, _ := copystructure.Copy(&res)

tests/koanf_test.go

@@ -2046,3 +2046,26 @@ func TestFileProviderConcurrency(t *testing.T) {
 		t.Fatal("FILE PROVIDER DEADLOCK: Goroutines did not complete within timeout")
 	}
 }
+
+// TestGetNilPointer tests Get()'ing nil pointers.
+func TestGetNilPointer(t *testing.T) {
+	assert := assert.New(t)
+	k := koanf.New(".")
+
+	type test struct {
+		Name string
+	}
+	var nt *test
+	assert.Nil(k.Set("key", nt))
+	assert.True(k.Exists("key"))
+	assert.Nil(k.Get("key"))
+
+	// Test nil value.
+	assert.Nil(k.Set("val", nil))
+	assert.Nil(k.Get("val"))
+
+	// Test slice.
+	var s *[]string
+	assert.Nil(k.Set("slice", s))
+	assert.Nil(k.Get("slice"))
+}