Avoid exception when closing a repository window

It seems to be caused by PBGitHistoryList holding a weak reference
to PBGitRepository but also observing it via KVO which may lead to
the PBGitRepository object to be deallocated before the KVO-observer
is removed.

Attempt to solve this by implementing explicit setters in PBGitHistory
which also call the update actions that were previously triggered
by KVO.

If the atomicity of those fields was crucial before, this may require
a bit more work.

Author: ssp

Classes/git/PBGitHistoryList.m

@@ -51,9 +51,6 @@ - (id) initWithRepository:(PBGitRepository *)repo
 	commits = [NSMutableArray array];
 	repository = repo;
 	lastBranchFilter = -1;
-	[repository addObserver:self forKeyPath:@"currentBranch" options:0 context:@"currentBranch"];
-	[repository addObserver:self forKeyPath:@"currentBranchFilter" options:0 context:@"currentBranch"];
-	[repository addObserver:self forKeyPath:@"hasChanged" options:0 context:@"repositoryHasChanged"];
 
 	shouldReloadProjectHistory = YES;
 	projectRevList = [[PBGitRevList alloc] initWithRepository:repository rev:[PBGitRevSpecifier allBranchesRevSpec] shouldGraph:NO];
@@ -96,9 +93,6 @@ - (void)cleanup
 	}
 	[graphQueue cancelAllOperations];
 
-	[repository removeObserver:self forKeyPath:@"currentBranch"];
-	[repository removeObserver:self forKeyPath:@"currentBranchFilter"];
-	[repository removeObserver:self forKeyPath:@"hasChanged"];
 }
 
 
@@ -350,19 +344,8 @@ - (void) updateHistoryForRev:(PBGitRevSpecifier *)rev
 
 #pragma mark -
 #pragma mark Key Value Observing
-
 - (void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
 {
-	if ([@"currentBranch" isEqualToString:(__bridge NSString*)context]) {
-		[self updateHistory];
-		return;
-	}
-
-	if ([@"repositoryHasChanged" isEqualToString:(__bridge NSString*)context]) {
-		[self forceUpdate];
-		return;
-	}
-
 	if ([@"commitsUpdated" isEqualToString:(__bridge NSString*)context]) {
 		NSInteger changeKind = [(NSNumber *)[change objectForKey:NSKeyValueChangeKindKey] intValue];
 		if (changeKind == NSKeyValueChangeInsertion) {

Classes/git/PBGitRepository.h

@@ -50,8 +50,8 @@ static NSString * PBStringFromBranchFilterType(PBGitXBranchFilterType type) {
 
 @interface PBGitRepository : NSDocument
 
-@property (assign) BOOL hasChanged;
-@property (assign) NSInteger currentBranchFilter;
+@property (nonatomic, assign) BOOL hasChanged;
+@property (nonatomic, assign) NSInteger currentBranchFilter;
 
 @property (readonly, strong) PBGitWindowController *windowController;
 @property (readonly, getter = getIndexURL) NSURL* indexURL;

Classes/git/PBGitRepository.m

@@ -40,8 +40,7 @@ @interface PBGitRepository () {
 
 @implementation PBGitRepository
 
-@synthesize revisionList, branchesSet, currentBranch, refs, hasChanged;
-@synthesize currentBranchFilter;
+@synthesize revisionList, branchesSet, currentBranch, currentBranchFilter, hasChanged, refs;
 
 #pragma mark -
 #pragma mark Memory management
@@ -478,6 +477,22 @@ - (void) readCurrentBranch
 		self.currentBranch = [self addBranch: [self headRef]];
 }
 
+- (void) setCurrentBranch:(PBGitRevSpecifier *)newCurrentBranch {
+	currentBranch = newCurrentBranch;
+	[revisionList updateHistory];
+}
+
+- (void) setCurrentBranchFilter:(NSInteger)newCurrentBranchFilter {
+	currentBranchFilter = newCurrentBranchFilter;
+	[revisionList updateHistory];
+}
+
+- (void) setHasChanged:(BOOL)newHasChanged {
+	hasChanged = newHasChanged;
+	[revisionList forceUpdate];
+}
+
+
 #pragma mark Stashes
 
 - (NSArray *)stashes