From 8767a67dd4ca018870507a442b006032038b7889 Mon Sep 17 00:00:00 2001
From: Thomas Goyne <tg@realm.io>
Date: Fri, 25 Aug 2017 16:05:47 -0700
Subject: [PATCH] Fix more cases where assigning an RLMArray property to itself
 would clear the RLMArray

---
 CHANGELOG.md                     | 16 ++++++++++++++++
 Realm/ObjectStore                |  2 +-
 Realm/RLMAccessor.hpp            |  2 ++
 Realm/RLMAccessor.mm             | 26 ++++++++++----------------
 Realm/Tests/ArrayPropertyTests.m |  4 ++++
 5 files changed, 33 insertions(+), 17 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e89305202f..c5ec86bd8c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,19 @@
+x.x.x Release notes (yyyy-MM-dd)
+=============================================================
+
+### API Breaking Changes
+
+* None.
+
+### Enhancements
+
+* None.
+
+### Bugfixes
+
+* Fix more cases where assigning an RLMArray property to itself would clear the
+  RLMArray.
+
 2.10.0 Release notes (2017-08-21)
 =============================================================
 
diff --git a/Realm/ObjectStore b/Realm/ObjectStore
index 2a715a49c4..4de03a96f8 160000
--- a/Realm/ObjectStore
+++ b/Realm/ObjectStore
@@ -1 +1 @@
-Subproject commit 2a715a49c4880701025684677af7e56dda857be7
+Subproject commit 4de03a96f86848297c36e89b7e9da49bf8b4d46d
diff --git a/Realm/RLMAccessor.hpp b/Realm/RLMAccessor.hpp
index 8ff279eda6..dc8807b26f 100644
--- a/Realm/RLMAccessor.hpp
+++ b/Realm/RLMAccessor.hpp
@@ -68,6 +68,8 @@ class RLMAccessorContext {
     RLMOptionalId default_value_for_property(realm::ObjectSchema const&,
                                              std::string const& prop);
 
+    bool is_same_list(realm::List const& list, id v) const noexcept;
+
     template<typename Func>
     void enumerate_list(__unsafe_unretained const id v, Func&& func) {
         for (id value in v) {
diff --git a/Realm/RLMAccessor.mm b/Realm/RLMAccessor.mm
index 551ccc8c5f..8acd88d199 100644
--- a/Realm/RLMAccessor.mm
+++ b/Realm/RLMAccessor.mm
@@ -136,23 +136,13 @@ void setValue(__unsafe_unretained RLMObjectBase *const obj, NSUInteger colIndex,
               __unsafe_unretained id<NSFastEnumeration> const value) {
     RLMVerifyInWriteTransaction(obj);
 
-    realm::List list(obj->_realm->_realm, obj->_row.get_linklist(colIndex));
-    if ([(id)value respondsToSelector:@selector(isBackedByList:)] && [(id)value isBackedByList:list]) {
-        return; // self-assignment is a no-op
+    realm::List list(obj->_realm->_realm, *obj->_row.get_table(), colIndex, obj->_row.get_index());
+    RLMClassInfo *info = obj->_info;
+    if (list.get_type() == realm::PropertyType::Object) {
+        info = &obj->_info->linkTargetType(obj->_info->propertyForTableColumn(colIndex).index);
     }
-
-    list.remove_all();
-    if (!value || (id)value == NSNull.null) {
-        return;
-    }
-
-    RLMAccessorContext ctx(obj->_realm,
-                           obj->_info->linkTargetType(obj->_info->propertyForTableColumn(colIndex).index));
-    translateError([&] {
-        for (id element in value) {
-            list.add(ctx, element);
-        }
-    });
+    RLMAccessorContext ctx(obj->_realm, *info);
+    translateError([&] { list.assign(ctx, value, false); });
 }
 
 void setValue(__unsafe_unretained RLMObjectBase *const obj, NSUInteger colIndex,
@@ -863,3 +853,7 @@ static auto to_optional(__unsafe_unretained id const value, Fn&& fn) {
 {
     return RLMOptionalId{defaultValue(@(prop.c_str()))};
 }
+
+bool RLMAccessorContext::is_same_list(realm::List const& list, __unsafe_unretained id const v) const noexcept {
+    return [v respondsToSelector:@selector(isBackedByList:)] && [v isBackedByList:list];
+}
diff --git a/Realm/Tests/ArrayPropertyTests.m b/Realm/Tests/ArrayPropertyTests.m
index 9bb3e09566..9549eb8106 100644
--- a/Realm/Tests/ArrayPropertyTests.m
+++ b/Realm/Tests/ArrayPropertyTests.m
@@ -1037,6 +1037,8 @@ - (void)testUnmanagedAssignment {
     // Self-assignment is a no-op
     array2.intArray = array2.intArray;
     XCTAssertEqualObjects([array2.intArray valueForKey:@"self"], (@[io2, io3]));
+    array2[@"intArray"] = array2[@"intArray"];
+    XCTAssertEqualObjects([array2[@"intArray"] valueForKey:@"self"], (@[io2, io3]));
 }
 
 - (void)testManagedAssignment {
@@ -1070,6 +1072,8 @@ - (void)testManagedAssignment {
     // Self-assignment is a no-op
     array2.intArray = array2.intArray;
     XCTAssertEqualObjects([array2.intArray valueForKey:@"intCol"], (@[@2, @3]));
+    array2[@"intArray"] = array2[@"intArray"];
+    XCTAssertEqualObjects([array2[@"intArray"] valueForKey:@"intCol"], (@[@2, @3]));
 
     [realm cancelWriteTransaction];
 }