From d7a6fc084764cc387cfa50398e6cee9c376fb579 Mon Sep 17 00:00:00 2001
From: Zhisheng Huang <zsh@fb.com>
Date: Wed, 4 Dec 2019 15:30:33 -0800
Subject: [PATCH] Add a flag to control how the IGSectionObject's
 isEqualToDiffable: is implemented

Summary:
In the Feed view, all the -isEqualToDiffable: implementation only checks the pk, a.k.a the identifier.

Let's mimic that behavior.

Reviewed By: calimarkus

Differential Revision: D18714064

fbshipit-source-id: e1fe9624da2997ecc7ca9b684ddd471d77b7564c
---
 .../IGListTestUICollectionViewDataSource.h    |  5 ++++
 .../IGListTestUICollectionViewDataSource.m    | 30 +++++++++++++++++--
 2 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/Tests/Objects/IGListTestUICollectionViewDataSource.h b/Tests/Objects/IGListTestUICollectionViewDataSource.h
index 6a790e16..91d7d4bc 100644
--- a/Tests/Objects/IGListTestUICollectionViewDataSource.h
+++ b/Tests/Objects/IGListTestUICollectionViewDataSource.h
@@ -19,6 +19,11 @@
 
 + (instancetype)sectionWithObjects:(NSArray *)objects identifier:(NSString *)identifier;
 
+/**
+ @param usesIdentifierForDiffable YES if we only use the `identifier` for -isEqualToDiffableObject. NO then we compares both the `identifier` as well as `objects`.
+ */
++ (instancetype)sectionWithObjects:(NSArray *)objects identifier:(NSString *)identifier usesIdentifierForDiffable:(BOOL)usesIdentifierForDiffable;
+
 @end
 
 @interface IGListTestUICollectionViewDataSource : NSObject <UICollectionViewDataSource>
diff --git a/Tests/Objects/IGListTestUICollectionViewDataSource.m b/Tests/Objects/IGListTestUICollectionViewDataSource.m
index cda06c9f..2dfbfbad 100644
--- a/Tests/Objects/IGListTestUICollectionViewDataSource.m
+++ b/Tests/Objects/IGListTestUICollectionViewDataSource.m
@@ -9,18 +9,26 @@
 
 #import "IGListTestUICollectionViewDataSource.h"
 
+#import <IGAssert/IGAssert.h>
+
 @implementation IGSectionObject {
     NSString *_identifier;
+    BOOL _usesIdentifierForDiffable;
 }
 
 + (instancetype)sectionWithObjects:(NSArray *)objects {
-    return [IGSectionObject sectionWithObjects:objects identifier:[NSUUID UUID].UUIDString];
+    return [IGSectionObject sectionWithObjects:objects identifier:[NSUUID UUID].UUIDString usesIdentifierForDiffable:NO];
 }
 
 + (instancetype)sectionWithObjects:(NSArray *)objects identifier:(NSString *)identifier {
+    return [IGSectionObject sectionWithObjects:objects identifier:identifier usesIdentifierForDiffable:NO];
+}
+
++ (instancetype)sectionWithObjects:(NSArray *)objects identifier:(NSString *)identifier usesIdentifierForDiffable:(BOOL)usesIdentifierForDiffable {
     IGSectionObject *object = [[IGSectionObject alloc] init];
     object.objects = objects;
     object->_identifier = [identifier copy];
+    object->_usesIdentifierForDiffable = usesIdentifierForDiffable;
     return object;
 }
 
@@ -34,8 +42,24 @@
     if (object == self) {
         return YES;
     } else if ([object isKindOfClass:IGSectionObject.class]) {
-        return (self.objects && [self.objects isEqualToArray:[object objects]])
-        || (!self.objects && ![object objects]);
+        IGSectionObject *sectionObject = (IGSectionObject *)object;
+        if (_usesIdentifierForDiffable) {
+            return [_identifier isEqualToString:sectionObject->_identifier];
+        } else {
+            return [self isEqual:object];
+        }
+    } else {
+        return NO;
+    }
+}
+
+- (BOOL)isEqual:(id)object {
+    if (object == self) {
+        return YES;
+    } else if ([object isKindOfClass:IGSectionObject.class]) {
+        IGSectionObject *sectionObject = (IGSectionObject *)object;
+        return ([self.objects isEqualToArray:sectionObject.objects]
+                && [_identifier isEqualToString:sectionObject->_identifier]);
     } else {
         return NO;
     }