JP Simard jpsim

When a LazyVStack is nested within a ScrollView on iOS 17, the scroll view's content offset can be incorrectly set for a brief moment, causing the scroll view to "jitter".

Here's some sample code:

import SwiftUI

struct ContentView: View {
    @State var isExpanded = Set<Int>()
    var body: some View {

This gist documents the steps to analyze the binary size allocation for SwiftLint (and other SwiftPM-based executables).

First, install Bloaty McBloatface: https://github.com/google/bloaty

Then run the following:

$ swift build -c release
$ ditto .build/release/swiftlint swiftlint-stripped
$ strip -rSTX swiftlint-stripped

With the following code:

import SwiftUI

struct ContentView: View {
    @State private var showPopover = false

    var body: some View {
 NavigationView {

An Xcode project generates the following archive:

$ tree Yams-macosx.xcarchive
Yams-macosx.xcarchive
├── Info.plist
├── Products
│   └── Library
│       └── Frameworks
│           └── Yams.framework

Running jazzy from a fresh Ubuntu machine:

Create a brand new Ubuntu machine

$ doctl compute droplet create jazzy --size 16gb \
    --image ubuntu-16-10-x64 --region sfo1
$ doctl compute ssh jazzy

Install Swift

Build & run a subset of Swift tests on Linux

# Spin up a beefy Digital Ocean droplet
doctl compute droplet create swift-dev --size m-224gb --image ubuntu-16-10-x64 --region sfo2 --ssh-keys XXXXXXX
doctl compute ssh swift-dev
# Install dependencies
apt-get update
apt-get install git cmake ninja-build clang python uuid-dev libicu-dev icu-devtools libbsd-dev libedit-dev libxml2-dev libsqlite3-dev swig libpython-dev libncurses5-dev pkg-config libblocksruntime-dev libcurl4-openssl-dev autoconf libtool systemtap-sdt-dev tzdata
# Clone &amp; build Swift

	NSInternalInconsistencyException: Call must be made on main thread
	0 CoreFoundation 0x196c40cb4 __exceptionPreprocess + 164 (NSException.m:202)
	1 libobjc.A.dylib 0x18fcd83d0 objc_exception_throw + 60 (objc-exception.mm:356)
	2 Foundation 0x1913ce54c -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 188 (NSException.m:242)
	3 UIKitCore 0x1999f3da0 -[UIApplication _performBlockAfterCATransactionCommitSynchronizes:] + 404 (UIApplication.m:3377)
	4 UIKitCore 0x199a00318 -[UIApplication _updateStateRestorationArchiveForBackgroundEvent:saveState:exitIfCouldNotRestoreState:updateSnapshot:windowScene:] + 528 (UIApplication.m:11822)
	5 UIKitCore 0x199a005dc -[UIApplication _updateSnapshotAndStateRestorationWithAction:windowScene:] + 144 (UIApplication.m:11867)
	6 <REDACTED> 0x104bbbc04 @objc closure #1 in <REDACTED>.userNotificationCenter(_:

	import AppKit
	import Compression
	import CoreImage
	import Foundation
	import Vision

	// MARK: - Get QR code image from specified path

	guard CommandLine.arguments.count == 2 else {
	print("Usage: scan-shc [path-to-qr-image]")

	extension Array {
	func parallelMap<T>(transform: (Element) -> T) -> [T] {
	var result = ContiguousArray<T?>(repeating: nil, count: count)
	return result.withUnsafeMutableBufferPointer { buffer in
	DispatchQueue.concurrentPerform(iterations: buffer.count) { idx in
	buffer[idx] = transform(self[idx])
	}
	return buffer.map { $0! }
	}
	}

	#import <Foundation/Foundation.h>
	#import <QuartzCore/QuartzCore.h>
	#import <iostream>
	#import <vector> // Needed for gist to compile.
	#pragma mark - Pure Implementation Functions
	const static unichar kUTF16Newline = (unichar)'\n'; // old naming habits die hard!
	/**
	* Calculates an array of line end "positions" for a given string.
	* The equivalent Swift function was `(String) -> [Int]` or `(NSString) -> [Int]`
	*