Xcode previews fail with JIT error

UI Frameworks SwiftUI
bryan1anderson OP
Created Jun ’24
Replies 11
Boosts 5
Views 1.2k
Participants 12

== PREVIEW UPDATE ERROR:

JITError

==================================

|  NoBuiltTargetDescriptionCouldBeFound
|  
|  translationUnit: PreviewTranslationUnit(moduleNamePrefix: "Previews_EmptyFeedRow", sourceIdentifier: file:///Users/bryananderson/Developer/JournalApp/JournalApp/Interface/Feed/EmptyFeedRow.swift -> EmptyFeedRow.swift, parseTree: ParseTree(version: 727, statements: 3, providers: 1), update: nil, changesContextMemoizer: PreviewsPipeline.PreviewTranslationUnit.(unknown context at $34b4b9c4c).ChangesContextMemoizer(parseTree: ParseTree(version: 727, statements: 3, providers: 1), sourceIdentifier: file:///Users/bryananderson/Developer/JournalApp/JournalApp/Interface/Feed/EmptyFeedRow.swift -> EmptyFeedRow.swift, cachedValue: os.OSAllocatedUnfairLock<Swift.Optional<PreviewsModel.ParseTree.PreviewChangesContext>>(__lock: Swift.ManagedBuffer<Swift.Optional<PreviewsModel.ParseTree.PreviewChangesContext>, __C.os_unfair_lock_s>)), registryDeclarationMemoizer: PreviewsPipeline.PreviewTranslationUnit.(unknown context at $34b4b9bec).RegistryDeclarationMemoizer)
|  
|  builtTargetDescriptions:
|

== VERSION INFO:

Tools: 16A5171c
OS:    24A5264n
PID:   906
Model: MacBook Pro
Arch:  arm64e

== ENVIRONMENT:

openFiles = [
    /Users/bryananderson/Developer/JournalApp/JournalApp/Interface/Feed/EmptyFeedRow.swift
]
wantsNewBuildSystem = true
newBuildSystemAvailable = true
activeScheme = JournalApp
activeRunDestination = iPhone 15 Pro variant iphonesimulator arm64
workspaceArena = [x]
buildArena = [x]
buildableEntries = [
    Remember.app
]
runMode = JIT Executor

== SELECTED RUN DESTINATION:

name = iPhone 15 Pro
eligible = true
sdk = Optional(<DVTSDK:0x13870da30:'iphonesimulator18.0':Simulator - iOS 18.0:<DVTFilePath:0x600001e8c700:'/Applications/Xcode-beta.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator18.0.sdk'>>)
variant = Optional("iphonesimulator")
device = Optional(<DVTiPhoneSimulator: 0x32f00d290> {
		SimDevice: iPhone 15 Pro (CF3C85BC-F559-4437-9072-7F30153B399B, iOS 18.0, Booted)
			PairedSim: <DVTiPhoneSimulator: 0x33733d150> {
		SimDevice: Apple Watch Series 9 (45mm) (627CE93E-EB02-4200-BE40-3DCB5C91DB44, watchOS 11.0, Shutdown)
}
})

== SELECTED RUN DESTINATION:

Simulator - iOS 18.0 | iphonesimulator | arm64 | iPhone 15 Pro | Apple Watch Series 9 (45mm)
jit enabled: true
fallback to dynamic replacement: false
Replies  11
Boosts  5
Views  1.2k
Participants  12
bryan1anderson OP
Jun ’24

error log
0
bryan1anderson OP
Jun ’24

CrashReportError: Fatal Error in UVJITAgent.swift

App crashed due to fatalError in UVJITAgent.swift at line 58.

JIT linker connection terminated due to remote disconnect
0
Kwiky OP
Jun ’24

Same here. This is awful

0
Frameworks Engineer OP
Apple
Jul ’24

Can you try again with Xcode 16 Beta 2 that came out recently and let us know how it goes?

0
dsbirch OP
Jul ’24

I just updated to Xcode 16 beta 3. A very simple Mac app I developed in beta 2 that previewed successfully just prior to the Xcode upgrade has started crashing on preview with the "fatalError in UVJITAgent.swift" message. It builds and runs successfully. It's only a problem previewing the app's one view.

2
iQQator@RBC OP
Jul ’24

Create empty project with type App in MacOS Sequoia in Xcode 16 beta 3

import SwiftUI

struct ContentView: View {
    var body: some View {
        Text("abcdef")
    }
}

#Preview {
    ContentView()
}

Preview provides crash :)

2
SubvertDev OP
Jul ’24

Same error. MacOS Sequoia Public Beta + Xcode 16 Beta 3. Every preview crashes after some time and doesn't recover until I close and reopen Xcode.

0
huwsername OP
Aug ’24

I am seeing this on Xcode 16.1 beta 1

0
JoshWood OP
Oct ’24

Version 16.0 (16A242d)

any solutions?

0
funktional-ee OP
2w

This is still unresolved as of Xcode Version 16.1 (16B40) and the 16.2 beta.

However, I am not seeing this on all projects. I am noting this specifically on projects which use an XCFramework we are building. It works just fine on-device, but is crashing previews with this JITError.

In our case, it claims that all(?) of the symbols declared in our XCFramework component could not be found.

For our case, we were generally able to get the projects working again by using Legacy Previews Execution, but this is obviously not great.

For a "realistic" example project, see https://github.com/stadiamaps/ferrostar. For a much more minimal project, see https://github.com/ianthetechie/uniffi-starter.

We're tracking this in https://github.com/stadiamaps/ferrostar/issues/344

0
jzatlo OP
4h

Still having JIT errors on device preview

0
Xcode previews fail with JIT error
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