fixed crash when setting custom shadow props to null

Reviewed By: emilsjolander

Differential Revision: D3923634

fbshipit-source-id: 005e316e70fa280960c796375b2e94f9967a089d

Author: majak

React/Views/RCTComponentData.m

@@ -145,22 +145,34 @@ - (RCTPropBlock)propBlockForKey:(NSString *)name
     // Check for custom setter
     if ([keyPath isEqualToString:@"__custom__"]) {
 
-      // Get custom setter
-      SEL customSetter = NSSelectorFromString([NSString stringWithFormat:@"set_%@:for%@View:withDefaultView:", name, shadowView ? @"Shadow" : @""]);
+      // Get custom setter. There is no default view in the shadow case, so the selector is different.
+      NSString *selectorString;
+      if (!shadowView) {
+        selectorString = [NSString stringWithFormat:@"set_%@:for%@View:withDefaultView:", name, shadowView ? @"Shadow" : @""];
+      } else {
+        selectorString = [NSString stringWithFormat:@"set_%@:forShadowView:", name];
+      }
+      SEL customSetter = NSSelectorFromString(selectorString);
 
       propBlock = ^(id<RCTComponent> view, id json) {
         RCTComponentData *strongSelf = weakSelf;
         if (!strongSelf) {
           return;
         }
         json = RCTNilIfNull(json);
-        if (!json && !strongSelf->_defaultView) {
-          // Only create default view if json is null
-          strongSelf->_defaultView = [strongSelf createViewWithTag:nil];
+        if (!shadowView) {
+          if (!json && !strongSelf->_defaultView) {
+            // Only create default view if json is null
+            strongSelf->_defaultView = [strongSelf createViewWithTag:nil];
+          }
+          ((void (*)(id, SEL, id, id, id))objc_msgSend)(
+            strongSelf.manager, customSetter, json, view, strongSelf->_defaultView
+          );
+        } else {
+          ((void (*)(id, SEL, id, id))objc_msgSend)(
+            strongSelf.manager, customSetter, json, view
+          );
         }
-        ((void (*)(id, SEL, id, id, id))objc_msgSend)(
-          strongSelf.manager, customSetter, json, view, strongSelf->_defaultView
-        );
       };
 
     } else {

React/Views/RCTViewManager.h

@@ -126,10 +126,10 @@ RCT_REMAP_VIEW_PROPERTY(name, __custom__, type)         \
 /**
  * This macro can be used when you need to provide custom logic for setting
  * shadow view properties. The macro should be followed by a method body, which can
- * refer to "json", "view" and "defaultView" to implement the required logic.
+ * refer to "json" and "view".
  */
 #define RCT_CUSTOM_SHADOW_PROPERTY(name, type, viewClass) \
 RCT_REMAP_SHADOW_PROPERTY(name, __custom__, type)         \
-- (void)set_##name:(id)json forShadowView:(viewClass *)view withDefaultView:(viewClass *)defaultView
+- (void)set_##name:(id)json forShadowView:(viewClass *)view
 
 @end