A command line tool for repairing Xcode xcasset sets which have gained a bunch of "unassigned image" warnings. Strips any dictionaries which have no "filename" reference from the images dictionary. Point it at the .imageset folder you wish to repair.

imageset-repair

//
//  main.m
//  imageset-repair
//
//  Created by Warren Burton on 25/07/2014.
//  Create a new Xcode commmand line project and paste into main.m
//  Use with a source control system 
//  May have unintended consequnces so you will want the ability to revert.
//

#import <Foundation/Foundation.h>

void recursiveRepairAtPath(NSString *path);

int main(int argc, const char * argv[])
{

    @autoreleasepool {
        
        NSString *string = nil;
        
        if (argc < 2) {
            
            char buffer[1024];
            
            getcwd((char *)&buffer, 1024);
            
            string = [NSString stringWithUTF8String:(char *)&buffer];
            
            NSLog(@"Yo, World! - %@",string);
            
        }
        else {
            
            string = [NSString stringWithUTF8String:argv[1]];
            
        }
        
        recursiveRepairAtPath(string);
        
        
        
    }
    return 0;
}

void recursiveRepairAtPath(NSString *path) {
    
    NSArray *items = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:path error:NULL];
    
    for (NSString *xpath in items) {
        
        if ([[xpath pathExtension] isEqualToString:@"imageset"]) {
            
            NSString *target = [[path stringByAppendingPathComponent:xpath] stringByAppendingPathComponent:@"Contents.json"];
            
            NSData *json = [NSData dataWithContentsOfFile:target];
            
            if (json.length > 0) {
                
                NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:json options:0 error:NULL];
                
                NSMutableDictionary *mdict = [dict mutableCopy];
                
                NSMutableArray *images = [dict[@"images"] mutableCopy];
                
                NSEnumerator *revEnum = [images reverseObjectEnumerator];
                
                NSDictionary *idict = nil;
                
                while (idict = [revEnum nextObject]) {
                    
                    if (!idict[@"filename"]) {
                        [images removeObject:idict];
                        NSLog(@"fixing - %@",target);
                    }
                    
                }
                
                mdict[@"images"] = images;
                
                BOOL res = [[NSJSONSerialization dataWithJSONObject:mdict options:0 error:NULL] writeToFile:target atomically:YES];
                
                NSLog(@"%d - %@",res,target);

            }
            
            
        }
        
    }
    
}