Autoreleased NSMutableArray not populated - iphone

Question

I want to populate an array like this:
NSMutableArray *array = [self methodThatReturnsAnArray];
In the "methodThatReturnsAnArray"-method I create an array like this:
NSMutableArray *arrayInMethod = [[NSMutableArray alloc] init];
When I'm finished populating "arrayInMethod" I'm returning the array and in order to prevent a memory leak I'm using:
return [arrayInMethod autorelease];
However the "array"-variable is never populated. When removing the "autorelease" it works fine though. What should I do in order to make sure that the returned object i released?
EDIT
+ (NSMutableArray *)buildInstants:(NSArray *)huntsArray {
NSMutableArray *goGetObjects = [[[NSMutableArray alloc] init] autorelease];
for (int i = 0; i < [huntsArray count]; i++) {
NSDictionary *huntDict = [huntsArray objectAtIndex:i];
PHGoGet *goGet = [[PHGoGet alloc] init];
goGet.title = [huntDict objectForKey:#"title"];
goGet.description = [huntDict objectForKey:#"description"];
goGet.start = [huntDict objectForKey:#"start"];
goGet.end = [huntDict objectForKey:#"end"];
goGet.ident = [huntDict objectForKey:#"id"];
if ((CFNullRef)[huntDict objectForKey:#"image_url"] != kCFNull) {
goGet.imageURL = [huntDict objectForKey:#"image_url"];
} else {
goGet.imageURL = nil;
}
if ((CFNullRef)[huntDict objectForKey:#"icon_url"] != kCFNull) {
goGet.iconURL = [huntDict objectForKey:#"icon_url"];
} else {
goGet.iconURL = nil;
}
goGet.longitude = [huntDict objectForKey:#"lng"];
goGet.latitude = [huntDict objectForKey:#"lat"];
goGet.companyIdent = [huntDict objectForKey:#"company_id"];
[goGetObjects insertObject:goGet atIndex:i];
[goGet release];
}
return [[goGetObjects copy] autorelease];
}

Answer 1

Try using the convienence method for NSMutableArray... change:
NSMutableArray *arrayInMethod = [[NSMutableArray alloc] init];
To...
NSMutableArray *arrayInMethod = [NSMutableArray array];
array will return an autoreleased object.

Answer 2

First of all, I recommend you not to return a NSMutableArray from any method. It's better to use NSArray for that to avoid some very difficult to debug problems. My proposition is:
You declare the mutable array and populate it:
NSMutableArray *arrayInMethod = [[[NSMutableArray alloc] init] autorelease];
Then you return an autoreleased copy:
return [[arrayInMethod copy] autorelease];
And finally, when you take the returned array, you make it mutable again (only if you need to change it):
NSMutableArray *array = [[self methodThatReturnsAnArray] mutableCopy];
When you're done with the array, you release it:
[array release];