Warning: "The receiver of message 'sizeWithFont:constrainedToSize:lineBreakMode:' is nil..."

I got this warning:

"The receiver of message 'sizeWithFont:constrainedToSize:lineBreakMode:' is nil and returns a value of type 'CGSize' that will be garbage"

I don't get it. What am I doing wrong?

Here's the code I'm using:

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {

        NSString *text = nil;
        NSUInteger row = indexPath.row;

    if (indexPath.section == FIRST_SECTION) {
        text = [_firstArray objectAtIndex:row];
    } else if (indexPath.section == SECOND_SECTION) {
        text = [_secondArray objectAtIndex:row];
    } else {
           text = nil;
        NSLog(@"Wrong section");
    }

    UITableViewCell *cell = [self myCell];
    UILineBreakMode lineBreakMode = cell.textLabel.lineBreakMode;

    CGFloat width = _tableView.contentSize.width - (kTableCellHPadding*2 + tableCellMargin*2);
    UIFont* font = cell.textLabel.font;
    CGSize size = [text sizeWithFont:font
     开发者_开发问答              constrainedToSize:CGSizeMake(width, CGFLOAT_MAX)
                       lineBreakMode:lineBreakMode];

    if (size.height > kMaxLabelHeight) size.height = kMaxLabelHeight;

    return size.height + kTableCellVPadding*2;

}

---

The cause is the following code segment:

if (indexPath.section == FIRST_SECTION) {
    text = [_firstArray objectAtIndex:row];
} else if (indexPath.section == SECOND_SECTION) {
    text = [_secondArray objectAtIndex:row];
} else {
    NSLog(@"Wrong section");
}

In that in the else part, no value is assigned to the text variable. So, it remains as nil. So, XCode complains about it being null.