Swift Playground crashes

Question

Created Jul ’25

Replies 2

Boosts 1

Participants 3

I'm trying to use the new #Playground feature in Xcode, but it keeps crashing in the canvas. I am testing on Xcode 26.0 beta 4, on both macOS 15 and macOS26 beta 4. How do I figure out what's going on?

I also have a few SwiftUI previews in my project, which also crashes if I try to preview them. They're not in any active tab right now in Xcode. But the #Playground feature still doesn't work.

I also don't get a crash when working on a #Playground in a different project.

I've tried cleaning out Derived Data and restarting the Mac / Xcode, all with no avail. How do I track down what's causing this? Do previews and playground run on the same engine?


System Integrity Protection: enabled

Triggered by Thread: 0

Exception Type:    EXC_CRASH (SIGABRT)
Exception Codes:   0x0000000000000000, 0x0000000000000000

Termination Reason:  Namespace OBJC, Code 1, 


Thread 0 Crashed:
0   libsystem_kernel.dylib        	       0x100634ad0 __abort_with_payload + 8
1   libsystem_kernel.dylib        	       0x100659dc0 abort_with_payload_wrapper_internal + 100
2   libsystem_kernel.dylib        	       0x100659d5c abort_with_reason + 28
3   libobjc.A.dylib               	       0x18009bd08 _objc_fatalv(unsigned long long, unsigned long long, char const*, char*) + 112
4   libobjc.A.dylib               	       0x18009bc98 _objc_fatal(char const*, ...) + 28
5   libobjc.A.dylib               	       0x18008be14 lookUpImpOrForward + 580
6   libobjc.A.dylib               	       0x180072f00 _objc_msgSend_uncached + 64
7   ???                           	       0x340a44048 ???
8   CJournal                      	       0x1001c54c4 __debug_blank_executor_run_user_entry_point + 152
9   PreviewsInjection             	       0x241623bf4 0x2415ff000 + 150516
10  PreviewsInjection             	       0x24162481c 0x2415ff000 + 153628
11  PreviewsInjection             	       0x241624740 __previews_injection_run_user_entrypoint + 12
12  XOJITExecutor                 	       0x25543ad48 __xojit_executor_run_program_wrapper + 1460
13  XOJITExecutor                 	       0x25543725c 0x255435000 + 8796
14  PreviewsInjection             	       0x24162468c 0x2415ff000 + 153228
15  CJournal                      	       0x1001c4c7c __debug_blank_executor_main + 996
16  ???                           	       0x1003e13d0 ???
17  dyld                          	       0x100218924 start + 6400

Boost

Answer 1

Developer Tools Engineer OP

Apple

Jul ’25

Yes, #Playground execution uses the same engine as Previews in Xcode.

Could you try this workaround: with the preview/playground canvas open, select the menu item Editor / Canvas / Use Legacy Previews Execution to enable that mode. Do previews and playgrounds now work?

In either case, please file a feedback report for the case when execution is failing, attaching previews diagnostics (from the diagnostics button in the canvas). Thanks!

1

Answer 2

cajazzer OP

Jul ’25

I tried the Legacy Previews Execution and it worked for a simple print(), however I am trying to use it with importing FoundationModels to use LanguageModelSession, and it fails with "Cannot find playgrounds". This worked in beta 3 BTW.

0