Merge pull request #2614 from jsfb/monitor-should-update-owner-is-useful

Find cases where shouldUpdateReactComponent is det

Author: jimfb

src/core/shouldUpdateReactComponent.js

@@ -12,6 +12,8 @@
 
 "use strict";
 
+var monitorCodeUse = require('monitorCodeUse');
+
 /**
  * Given a `prevElement` and `nextElement`, determines if the existing
  * instance should be updated as opposed to being destroyed or replaced by a new
@@ -30,12 +32,41 @@ function shouldUpdateReactComponent(prevElement, nextElement) {
     if (prevType === 'string' || prevType === 'number') {
       return (nextType === 'string' || nextType === 'number');
     } else {
-      return (
-        nextType === 'object' &&
-        prevElement.type === nextElement.type &&
-        prevElement.key === nextElement.key &&
-        prevElement._owner === nextElement._owner
-      );
+      if (nextType === 'object' &&
+          prevElement.type === nextElement.type &&
+          prevElement.key === nextElement.key) {
+        var ownersMatch = prevElement._owner === nextElement._owner;
+        var prevName = null;
+        var nextName = null;
+        var nextDisplayName = null;
+        if(__DEV__) {
+          if (!ownersMatch) {
+            if (prevElement._owner != null &&
+                prevElement._owner.getPublicInstance() != null &&
+                prevElement._owner.getPublicInstance().constructor != null) {
+              prevName = prevElement._owner.getPublicInstance().constructor.displayName;
+            }
+            if (nextElement._owner != null &&
+                nextElement._owner.getPublicInstance() != null &&
+                nextElement._owner.getPublicInstance().constructor != null) {
+              nextName = nextElement._owner.getPublicInstance().constructor.displayName;
+            }
+            if(nextElement.type != null && nextElement.type.displayName != null) {
+              nextDisplayName = nextElement.type.displayName;
+            }
+            monitorCodeUse(
+              'react_should_update_owner_is_useful',
+              {
+                key: prevElement.key,
+                prevOwner: prevName,
+                nextOwner: nextName,
+                nextDisplayName: nextDisplayName
+              }
+            );
+          }
+        }
+        return ownersMatch;
+      }
     }
   }
   return false;