From 2096558837c0f583044c6a98e7fb7542af6517d1 Mon Sep 17 00:00:00 2001
From: Tom Cherry <tomcherry@google.com>
Date: Wed, 22 Aug 2018 15:40:09 -0700
Subject: [PATCH] init: always allow clearing a property

An unintended consequence of property types is that it makes clearing
a property, by setting it to an empty string, impossible.  This change
explicitly allows that case:

Test: new (and old) unit tests
Change-Id: I188693bfd3a71b64c194c3858544230b87d8d891
---
 init/property_type.cpp      |  5 +++++
 init/property_type_test.cpp | 10 +++++-----
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/init/property_type.cpp b/init/property_type.cpp
index 249b12b99..7d805552b 100644
--- a/init/property_type.cpp
+++ b/init/property_type.cpp
@@ -29,6 +29,11 @@ namespace android {
 namespace init {
 
 bool CheckType(const std::string& type_string, const std::string& value) {
+    // Always allow clearing a property such that the default value when it is not set takes over.
+    if (value.empty()) {
+        return true;
+    }
+
     auto type_strings = Split(type_string, " ");
     if (type_strings.empty()) {
         return false;
diff --git a/init/property_type_test.cpp b/init/property_type_test.cpp
index 068bccc8d..6d7f9270b 100644
--- a/init/property_type_test.cpp
+++ b/init/property_type_test.cpp
@@ -32,7 +32,7 @@ TEST(property_type, CheckType_string) {
 }
 
 TEST(property_type, CheckType_int) {
-    EXPECT_FALSE(CheckType("int", ""));
+    EXPECT_TRUE(CheckType("int", ""));
     EXPECT_FALSE(CheckType("int", "abc"));
     EXPECT_FALSE(CheckType("int", "-abc"));
     EXPECT_TRUE(CheckType("int", "0"));
@@ -43,7 +43,7 @@ TEST(property_type, CheckType_int) {
 }
 
 TEST(property_type, CheckType_uint) {
-    EXPECT_FALSE(CheckType("uint", ""));
+    EXPECT_TRUE(CheckType("uint", ""));
     EXPECT_FALSE(CheckType("uint", "abc"));
     EXPECT_FALSE(CheckType("uint", "-abc"));
     EXPECT_TRUE(CheckType("uint", "0"));
@@ -53,7 +53,7 @@ TEST(property_type, CheckType_uint) {
 }
 
 TEST(property_type, CheckType_double) {
-    EXPECT_FALSE(CheckType("double", ""));
+    EXPECT_TRUE(CheckType("double", ""));
     EXPECT_FALSE(CheckType("double", "abc"));
     EXPECT_FALSE(CheckType("double", "-abc"));
     EXPECT_TRUE(CheckType("double", "0.0"));
@@ -64,7 +64,7 @@ TEST(property_type, CheckType_double) {
 }
 
 TEST(property_type, CheckType_size) {
-    EXPECT_FALSE(CheckType("size", ""));
+    EXPECT_TRUE(CheckType("size", ""));
     EXPECT_FALSE(CheckType("size", "ab"));
     EXPECT_FALSE(CheckType("size", "abcd"));
     EXPECT_FALSE(CheckType("size", "0"));
@@ -80,7 +80,7 @@ TEST(property_type, CheckType_size) {
 }
 
 TEST(property_type, CheckType_enum) {
-    EXPECT_FALSE(CheckType("enum abc", ""));
+    EXPECT_TRUE(CheckType("enum abc", ""));
     EXPECT_FALSE(CheckType("enum abc", "ab"));
     EXPECT_FALSE(CheckType("enum abc", "abcd"));
     EXPECT_FALSE(CheckType("enum 123 456 789", "0"));