From 8edb5a45d3d08001c4b1b9af9cf705a9fb8affaa Mon Sep 17 00:00:00 2001
From: Michael Schneider <maicki@users.noreply.github.com>
Date: Wed, 20 Feb 2019 11:21:47 -0800
Subject: [PATCH] Move ASSectionController and ASSupplementaryNodeSource method
 to be optional (#1302)

---
 Source/ASSectionController.h                     |  7 +++----
 Source/ASSupplementaryNodeSource.h               |  4 ++--
 Source/Private/ASIGListAdapterBasedDataSource.mm | 16 ++++++++++++----
 3 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/Source/ASSectionController.h b/Source/ASSectionController.h
index 5d48bbef1f..6807596138 100644
--- a/Source/ASSectionController.h
+++ b/Source/ASSectionController.h
@@ -16,13 +16,14 @@ NS_ASSUME_NONNULL_BEGIN
 @class ASBatchContext;
 
 /**
- * A protocol that your section controllers should conform to,
- * in order to be used with AsyncDisplayKit.
+ * A protocol that your section controllers should conform to, in order to be used with Texture.
  *
  * @note Your supplementary view source should conform to @c ASSupplementaryNodeSource.
  */
 @protocol ASSectionController <NSObject>
 
+@optional
+
 /**
  * A method to provide the node block for the item at the given index.
  * The node block you return will be run asynchronously off the main thread,
@@ -48,8 +49,6 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (ASCellNode *)nodeForItemAtIndex:(NSInteger)index;
 
-@optional
-
 /**
  * Asks the section controller whether it should batch fetch because the user is
  * near the end of the current data set.
diff --git a/Source/ASSupplementaryNodeSource.h b/Source/ASSupplementaryNodeSource.h
index 3d63a6900e..20bedddeec 100644
--- a/Source/ASSupplementaryNodeSource.h
+++ b/Source/ASSupplementaryNodeSource.h
@@ -15,6 +15,8 @@ NS_ASSUME_NONNULL_BEGIN
 
 @protocol ASSupplementaryNodeSource <NSObject>
 
+@optional
+
 /**
  * A method to provide the node-block for the supplementary element.
  *
@@ -33,8 +35,6 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (ASCellNode *)nodeForSupplementaryElementOfKind:(NSString *)kind atIndex:(NSInteger)index;
 
-@optional
-
 /**
  * A method to provide the size range used for measuring the supplementary
  * element of the given kind at the given index.
diff --git a/Source/Private/ASIGListAdapterBasedDataSource.mm b/Source/Private/ASIGListAdapterBasedDataSource.mm
index ade87eb581..3cf77afc0a 100644
--- a/Source/Private/ASIGListAdapterBasedDataSource.mm
+++ b/Source/Private/ASIGListAdapterBasedDataSource.mm
@@ -215,12 +215,16 @@ typedef struct {
 
 - (ASCellNodeBlock)collectionNode:(ASCollectionNode *)collectionNode nodeBlockForItemAtIndexPath:(NSIndexPath *)indexPath
 {
-  return [[self sectionControllerForSection:indexPath.section] nodeBlockForItemAtIndex:indexPath.item];
+  ASIGSectionController *ctrl = [self sectionControllerForSection:indexPath.section];
+  ASDisplayNodeAssert([ctrl respondsToSelector:@selector(nodeBlockForItemAtIndex:)], @"Expected section controller to respond to to %@. Controller: %@", NSStringFromSelector(@selector(nodeBlockForItemAtIndex:)), ctrl);
+  return [ctrl nodeBlockForItemAtIndex:indexPath.item];
 }
 
 - (ASCellNode *)collectionNode:(ASCollectionNode *)collectionNode nodeForItemAtIndexPath:(NSIndexPath *)indexPath
 {
-  return [[self sectionControllerForSection:indexPath.section] nodeForItemAtIndex:indexPath.item];
+  ASIGSectionController *ctrl = [self sectionControllerForSection:indexPath.section];
+  ASDisplayNodeAssert([ctrl respondsToSelector:@selector(nodeForItemAtIndex:)], @"Expected section controller to respond to to %@. Controller: %@", NSStringFromSelector(@selector(nodeForItemAtIndex:)), ctrl);
+  return [ctrl nodeForItemAtIndex:indexPath.item];
 }
 
 - (ASSizeRange)collectionNode:(ASCollectionNode *)collectionNode constrainedSizeForItemAtIndexPath:(NSIndexPath *)indexPath
@@ -235,12 +239,16 @@ typedef struct {
 
 - (ASCellNodeBlock)collectionNode:(ASCollectionNode *)collectionNode nodeBlockForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
 {
-  return [[self supplementaryElementSourceForSection:indexPath.section] nodeBlockForSupplementaryElementOfKind:kind atIndex:indexPath.item];
+  id<ASSupplementaryNodeSource> ctrl = [self supplementaryElementSourceForSection:indexPath.section];
+  ASDisplayNodeAssert([ctrl respondsToSelector:@selector(nodeBlockForSupplementaryElementOfKind:atIndex:)], @"Expected section controller to respond to to %@. Controller: %@", NSStringFromSelector(@selector(nodeBlockForSupplementaryElementOfKind:atIndex:)), ctrl);
+  return [ctrl nodeBlockForSupplementaryElementOfKind:kind atIndex:indexPath.item];
 }
 
 - (ASCellNode *)collectionNode:(ASCollectionNode *)collectionNode nodeForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
 {
-  return [[self supplementaryElementSourceForSection:indexPath.section] nodeForSupplementaryElementOfKind:kind atIndex:indexPath.item];
+  id<ASSupplementaryNodeSource> ctrl = [self supplementaryElementSourceForSection:indexPath.section];
+  ASDisplayNodeAssert([ctrl respondsToSelector:@selector(nodeForSupplementaryElementOfKind:atIndex:)], @"Expected section controller to respond to to %@. Controller: %@", NSStringFromSelector(@selector(nodeForSupplementaryElementOfKind:atIndex:)), ctrl);
+  return [ctrl nodeForSupplementaryElementOfKind:kind atIndex:indexPath.item];
 }
 
 - (NSArray<NSString *> *)collectionNode:(ASCollectionNode *)collectionNode supplementaryElementKindsInSection:(NSInteger)section