GTReference nullability

Author: phatblat

ObjectiveGit/GTReference.h

@@ -61,8 +61,8 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic, readonly, strong) GTReflog *reflog;
 
 /// Convenience initializers
-+ (id)referenceByResolvingSymbolicReference:(GTReference *)symbolicRef error:(NSError **)error;
-- (id)initByResolvingSymbolicReference:(GTReference *)symbolicRef error:(NSError **)error;
++ (nullable instancetype)referenceByResolvingSymbolicReference:(GTReference *)symbolicRef error:(NSError **)error;
+- (nullable instancetype)initByResolvingSymbolicReference:(GTReference *)symbolicRef error:(NSError **)error;
 
 /// Designated initializer.
 ///

ObjectiveGit/GTReference.m

@@ -70,11 +70,11 @@ - (BOOL)isRemote {
 	return git_reference_is_remote(self.git_reference) != 0;
 }
 
-+ (id)referenceByResolvingSymbolicReference:(GTReference *)symbolicRef error:(NSError **)error {
++ (instancetype)referenceByResolvingSymbolicReference:(GTReference *)symbolicRef error:(NSError **)error {
 	return [[self alloc] initByResolvingSymbolicReference:symbolicRef error:error];
 }
 
-- (id)initByResolvingSymbolicReference:(GTReference *)symbolicRef error:(NSError **)error {
+- (instancetype)initByResolvingSymbolicReference:(GTReference *)symbolicRef error:(NSError **)error {
 	NSParameterAssert(symbolicRef != nil);
 
 	git_reference *ref = NULL;

ObjectiveGit/GTRepository+References.h

@@ -8,6 +8,8 @@
 
 #import "GTrepository.h"
 
+NS_ASSUME_NONNULL_BEGIN
+
 @class GTReference;
 
 @interface GTRepository (References)
@@ -18,6 +20,8 @@
 /// error - The error if one occurs. May be NULL.
 ///
 /// Returns the reference or nil if look up failed.
-- (GTReference *)lookUpReferenceWithName:(NSString *)name error:(NSError **)error;
+- (nullable GTReference *)lookUpReferenceWithName:(NSString *)name error:(NSError **)error;
 
 @end
+
+NS_ASSUME_NONNULL_END