UICollectionView minimumLineSpacing bug

I'm creating a horizontal scroll view through the collection view.

I used flowlayout for layout, and I set the scroll direction to horizontal.

I found a bug in this situation.

If the width of the item is different, line spacing is not applied, but item spacing is applied.

Since it is a horizontal scroll, line spacing should be applied in the direction of the column, but item spacing is applied.

Does anyone know anything about this?

//
//  ViewController.swift
//  minimumLineSpacingTest
//
//  Created by Hoonki chae on 2023/07/12.
//

import UIKit

class TestCell: UICollectionViewCell {
    
}

class ViewController: UIViewController {

    let collectionView = UICollectionView(frame: .zero, collectionViewLayout: UICollectionViewFlowLayout())
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.view.backgroundColor = .white
        self.collectionView.frame = .init(origin: .init(x: 0, y: 100), size: .init(width: self.view.frame.width, height: 50))
        self.view.addSubview(self.collectionView)
        self.collectionView.backgroundColor = .systemGray.withAlphaComponent(0.2)
        self.collectionView.delegate = self
        self.collectionView.dataSource = self
        self.collectionView.register(TestCell.self, forCellWithReuseIdentifier: "Cell")
        (self.collectionView.collectionViewLayout as? UICollectionViewFlowLayout)?.scrollDirection = .horizontal
    }


}


extension ViewController: UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 5
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath)
        cell.backgroundColor = .green.withAlphaComponent(0.3)
        return cell
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return .init(width: indexPath.item > 2 ? 150 : 140, height: 50)
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return 20
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
        return 4
    }
    
}```

I had the same issue.

UICollectionView minimumLineSpacing bug
 
 
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