Open Radar

 
Summary:
The following code reliably produces a crash.

Steps to Reproduce:
import GameplayKit

class Broken {
    let graph: GKGridGraph
    
    init() {
        graph = GKGridGraph(fromGridStartingAt: [0, 0], width: 1, height: 1, diagonalsAllowed: false)
    }
}

var g: Broken?
autoreleasepool {
    g = Broken()
}

g = nil

Expected Results:
No crashes or errors.

Actual Results:
Playground execution failed: Execution was interrupted, reason: EXC_BAD_ACCESS (code=EXC_I386_GPFLT).
* thread #1: tid = 0x4576a, 0x0000000110d3d63f GameplayKit`-[GKGraphNode dealloc] + 31, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
  * frame #0: 0x0000000110d3d63f GameplayKit`-[GKGraphNode dealloc] + 31
    frame #1: 0x00007fff9ffbb2dd CoreFoundation`-[__NSArrayM dealloc] + 205
    frame #2: 0x00007fff95188b81 libobjc.A.dylib`object_cxxDestructFromClass(objc_object*, objc_class*) + 127
    frame #3: 0x00007fff95181383 libobjc.A.dylib`objc_destructInstance + 116
    frame #4: 0x00007fff951812e5 libobjc.A.dylib`object_dispose + 22
    frame #5: 0x0000000110d389d1 GameplayKit`-[GKGraph dealloc] + 65
    frame #6: 0x0000000110dc84b3 $__lldb_expr36`__lldb_expr_36.Broken.deinit(self=0x00007f81a3115c20) + 35 at <EXPR>:0
    frame #7: 0x0000000110dc8438 $__lldb_expr36`__lldb_expr_36.Broken.__deallocating_deinit + 24 at <EXPR>:0
    frame #8: 0x0000000110dc82d5 $__lldb_expr36`main + 725 at <EXPR>:0
    frame #9: 0x000000010bafd710 Gameplay`_mh_execute_header + 22288
    frame #10: 0x000000010bafeb31 Gameplay`reabstraction thunk helper from @callee_owned () -> (@unowned ()) to @callee_owned (@in ()) -> (@out ()) + 17
    frame #11: 0x000000010bafe881 Gameplay`partial apply forwarder for reabstraction thunk helper from @callee_owned () -> (@unowned ()) to @callee_owned (@in ()) -> (@out ()) + 81
    frame #12: 0x000000010bafebb0 Gameplay`reabstraction thunk helper from @callee_owned (@in ()) -> (@out ()) to @callee_owned () -> (@unowned ()) + 32
    frame #13: 0x000000010bafebe7 Gameplay`reabstraction thunk helper from @callee_owned () -> (@unowned ()) to @callee_unowned @convention(block) () -> (@unowned ()) + 39
    frame #14: 0x00007fffa003724c CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12
    frame #15: 0x00007fffa0016b65 CoreFoundation`__CFRunLoopDoBlocks + 341
    frame #16: 0x00007fffa001632e CoreFoundation`__CFRunLoopRun + 910
    frame #17: 0x00007fffa0015d38 CoreFoundation`CFRunLoopRunSpecific + 296
    frame #18: 0x00007fff98922d55 HIToolbox`RunCurrentEventLoopInMode + 235
    frame #19: 0x00007fff98922a97 HIToolbox`ReceiveNextEventCommon + 184
    frame #20: 0x00007fff989229cf HIToolbox`_BlockUntilNextEventMatchingListInModeWithFilter + 71
    frame #21: 0x00007fff92642236 AppKit`_DPSNextEvent + 1067
    frame #22: 0x00007fff92641665 AppKit`-[NSApplication _nextEventMatchingEventMask:untilDate:inMode:dequeue:] + 454
    frame #23: 0x00007fff926361c8 AppKit`-[NSApplication run] + 682
    frame #24: 0x000000010bafd9c8 Gameplay`main + 696
    frame #25: 0x00007fff932d75ad libdyld.dylib`start + 1
    frame #26: 0x00007fff932d75ad libdyld.dylib`start + 1


Version:
Xcode 7.1 beta (7B60)

Notes:
When width>1 or height>1, the crash does not occur.


Configuration:
OS X 10.11 (15A279b)