From 0fb0967ee089801d482ba758a23304df1f9decc1 Mon Sep 17 00:00:00 2001
From: Kenneth Geisshirt <kenneth.geisshirt@mongodb.com>
Date: Tue, 7 Jun 2022 11:16:55 +0200
Subject: [PATCH] Realm.Configuration.sync can be a boolean (#4616)
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* Realm.Configuration.sync can be a boolean

Co-authored-by: Kræn Hansen <kraen.hansen@mongodb.com>
---
 CHANGELOG.md     | 1 +
 src/js_realm.hpp | 7 ++++---
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4f27656193..b1163e5e6f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ x.x.x Release notes (yyyy-MM-dd)
 * <Either mention core version or upgrade>
 * <Using Realm Core vX.Y.Z>
 * <Upgraded Realm Core from vX.Y.Z to vA.B.C>
+* Fixed a bug preventing opening a synced Realm as a local Realm. (since v10.18.0)
 
 10.19.0 Release notes (2022-6-2)
 =============================================================
diff --git a/src/js_realm.hpp b/src/js_realm.hpp
index 4da97f02f5..79fa832005 100644
--- a/src/js_realm.hpp
+++ b/src/js_realm.hpp
@@ -838,7 +838,7 @@ void RealmClass<T>::handle_initial_subscriptions(ContextType ctx, size_t argc, c
     ObjectType config_object = Value::to_object(ctx, config_value);
 
     ValueType sync_value = Object::get_property(ctx, config_object, "sync");
-    if (Value::is_undefined(ctx, sync_value)) {
+    if (!Value::is_object(ctx, sync_value)) {
         return;
     }
     ObjectType sync_object = Value::validated_to_object(ctx, sync_value);
@@ -1564,8 +1564,9 @@ realm::Realm::Config RealmClass<T>::write_copy_to_helper(ContextType ctx, Object
     // validate 5)
     // check whether a sync config exists -- it is optional
     ValueType syncConfigValue = Object::get_property(ctx, output_config, "sync");
-    if (!Value::is_undefined(ctx, syncConfigValue) && !Value::is_object(ctx, syncConfigValue)) {
-        throw std::invalid_argument("'sync' property must be an object");
+    if (!Value::is_undefined(ctx, syncConfigValue) && !Value::is_object(ctx, syncConfigValue) &&
+        !Value::is_boolean(ctx, syncConfigValue)) {
+        throw std::invalid_argument("if set, 'sync' property must be an object or a boolean");
     }