GTFilterList nullability

Author: Ben Chatelain

ObjectiveGit/GTFilterList.h

@@ -18,6 +18,8 @@ typedef NS_OPTIONS(NSInteger, GTFilterListOptions) {
 	GTFilterListOptionsAllowUnsafe = GIT_FILTER_ALLOW_UNSAFE,
 };
 
+NS_ASSUME_NONNULL_BEGIN
+
 /// An opaque list of filters that apply to a given path.
 @interface GTFilterList : NSObject
 
@@ -26,7 +28,9 @@ typedef NS_OPTIONS(NSInteger, GTFilterListOptions) {
 /// filterList - The filter list to wrap and take ownership of. This filter list
 ///              will be automatically disposed when the receiver deallocates.
 ///              Must not be NULL.
-- (instancetype)initWithGitFilterList:(git_filter_list *)filterList NS_DESIGNATED_INITIALIZER;
+///
+/// Returns an initialized filter list, or nil if an error occurred.
+- (nullable instancetype)initWithGitFilterList:(git_filter_list *)filterList NS_DESIGNATED_INITIALIZER;
 
 /// Returns the underlying `git_filter_list`.
 - (git_filter_list *)git_filter_list __attribute__((objc_returns_inner_pointer));
@@ -37,7 +41,7 @@ typedef NS_OPTIONS(NSInteger, GTFilterListOptions) {
 /// error     - If not NULL, set to any error that occurs.
 ///
 /// Returns the filtered data, or nil if an error occurs.
-- (NSData *)applyToData:(NSData *)inputData error:(NSError **)error;
+- (nullable NSData *)applyToData:(NSData *)inputData error:(NSError **)error;
 
 /// Attempts to apply the filter list to a file in the given repository.
 ///
@@ -47,14 +51,16 @@ typedef NS_OPTIONS(NSInteger, GTFilterListOptions) {
 /// error        - If not NULL, set to any error that occurs.
 ///
 /// Returns the filtered data, or nil if an error occurs.
-- (NSData *)applyToPath:(NSString *)relativePath inRepository:(GTRepository *)repository error:(NSError **)error;
+- (nullable NSData *)applyToPath:(NSString *)relativePath inRepository:(GTRepository *)repository error:(NSError **)error;
 
 /// Attempts to apply the filter list to a blob.
 ///
 /// blob  - A blob of the data that should be filtered. Must not be nil.
 /// error - If not NULL, set to any error that occurs.
 ///
 /// Returns the filtered data, or nil if an error occurs.
-- (NSData *)applyToBlob:(GTBlob *)blob error:(NSError **)error;
+- (nullable NSData *)applyToBlob:(GTBlob *)blob error:(NSError **)error;
 
 @end
+
+NS_ASSUME_NONNULL_END