Merge "Differentiate between empty and nil input" into udc-dev am: 267a137415

Original change: https://googleplex-android-review.googlesource.com/c/platform/build/soong/+/23374038

Change-Id: If4189ee29bf9a44eb86e594a2b3a2d6f3d27cec3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

android/util.go

@@ -26,7 +26,11 @@ import (
 
 // CopyOf returns a new slice that has the same contents as s.
 func CopyOf(s []string) []string {
-	return append([]string(nil), s...)
+	// If the input is nil, return nil and not an empty list
+	if s == nil {
+		return s
+	}
+	return append([]string{}, s...)
 }
 
 // Concat returns a new slice concatenated from the two input slices. It does not change the input

android/util_test.go

@@ -381,6 +381,14 @@ func TestRemoveFromList(t *testing.T) {
 	}
 }
 
+func TestCopyOfEmptyAndNil(t *testing.T) {
+	emptyList := []string{}
+	copyOfEmptyList := CopyOf(emptyList)
+	AssertBoolEquals(t, "Copy of an empty list should be an empty list and not nil", true, copyOfEmptyList != nil)
+	copyOfNilList := CopyOf(nil)
+	AssertBoolEquals(t, "Copy of a nil list should be a nil list and not an empty list", true, copyOfNilList == nil)
+}
+
 func ExampleCopyOf() {
 	a := []string{"1", "2", "3"}
 	b := CopyOf(a)