Xcode 26 RC unable to compile asset catalogs on CI

This started with Xcode 26 beta 7, however it has continued to occur with the release candidate. Whenever I try to compile our asset catalog + icon composer icon for our AppKit/SwiftUI-based macOS app, actool fails with the following exception:

*** Terminating app due to uncaught exception 'IBPlatformToolFailureException', reason: 'The tool closed the connection (AssetCatalogAgent-AssetRuntime)

Last command:
_ON_QUEUE_sendMessage:toChannelReturningError:during:

Backtrace of last command:
  0   -[IBAbstractPlatformToolProxy _ON_QUEUE_sendMessage:toChannelReturningError:during:] (in IDEInterfaceBuilderKit)
  1   __74-[IBAbstractPlatformToolProxy sendMessage:toChannelReturningError:during:]_block_invoke (in IDEInterfaceBuilderKit)
  2   _dispatch_client_callout (in libdispatch.dylib)
  3   _dispatch_lane_barrier_sync_invoke_and_complete (in libdispatch.dylib)
  4   DVTDispatchSync (in DVTFoundation)
  5   -[IBAbstractPlatformToolProxy sendMessage:toChannelReturningError:during:] (in IDEInterfaceBuilderKit)
  6   -[AssetCatalogRemoteAgentProxy compileItemsWithCatalogRelativeIdentifierPaths:tagSolutionSpace:andStickerPacksWithCatalogRelativeIdentifierPaths:options:] (in IDEInterfaceBuilderCocoaTouchIntegration)
  7   -[IBICLARToolCARCompiler compileCARItems:tagSolutionSpace:options:queue:completionHandler:] (in AssetCatalogCocoaTouchKit)
  8   -[IBICAbstractPlatformAdapter compileCARItems:tagSolutionSpace:options:queue:completionHandler:] (in AssetCatalogFoundation)
  9   __84-[IBICAbstractPlatformAdapter compileSelectedItems:options:queue:completionHandler:]_block_invoke (in AssetCatalogFoundation)
 10   __93-[IBICAbstractPlatformAdapter compileStandaloneCatalogItems:options:queue:completionHandler:]_block_invoke (in AssetCatalogFoundation)
 11   __DVT_CALLING_CLIENT_BLOCK__ (in DVTFoundation)
 12   __DVTDispatchAsync_block_invoke (in DVTFoundation)
 13   _dispatch_call_block_and_release (in libdispatch.dylib)
 14   _dispatch_client_callout (in libdispatch.dylib)
 15   _dispatch_main_queue_drain.cold.5 (in libdispatch.dylib)
 16   _dispatch_main_queue_drain (in libdispatch.dylib)
 17   _dispatch_main_queue_callback_4CF (in libdispatch.dylib)
 18   __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ (in CoreFoundation)
 19   __CFRunLoopRun (in CoreFoundation)
 20   CFRunLoopRunSpecific (in CoreFoundation)
 21   -[NSRunLoop(NSRunLoop) runMode:beforeDate:] (in Foundation)
 22   -[NSRunLoop(DVTNSRunLoopAdditions) dvt_spinRunLoopInMode:whileQueue:executesAsynchronously:] (in DVTFoundation)
 23   -[NSRunLoop(DVTNSRunLoopAdditions) dvt_spinRunLoopInMode:whileBlockExecutesConcurrently:] (in DVTFoundation)
 24   -[NSRunLoop(DVTNSRunLoopAdditions) dvt_spinRunLoopInMode:waitingForSemaphore:] (in DVTFoundation)
 25   -[IBCLIImageCatalogToolPersona compileCatalogCollection:withPlatformAdapter:arguments:outputDictionary:] (in ibtoold)
 26   -[IBCLIImageCatalogToolPersona invokeArguments:outputDictionary:] (in ibtoold)
 27   -[IBCLIImageCatalogToolPersona runSingleInvocation:outputtingToFileHandle:andVerifyingEnvironment:] (in ibtoold)
 28   IBCLIServerRunSingleInvocation (in ibtoold)
 29   __IBCLIServerRunSingleInvocationWithIODirectedAtPipesAndUnlinkOnSuccess_block_invoke_2 (in ibtoold)
 30   __IBCLIServerRunSingleInvocationWithIODirectedAtPipesAndUnlinkOnSuccess_block_invoke (in ibtoold)
 31   -[IBCLIErrorForwarder forwardErrorOutputToDescriptor:whileInvokingBlock:] (in ibtoold)
 32   IBCLIServerRunSingleInvocationWithIODirectedAtPipesAndUnlinkOnSuccess (in ibtoold)
 33   main (in ibtoold)
 34   start (in dyld)

I can't seem to get it to compile consistently — it works fine locally.

I would ❤️ a workaround, otherwise I'm not sure that we'll be able to ship an update to our app for macOS 26.

FB20183399

Xcode 26 RC unable to compile asset catalogs on CI
 
 
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