[Scummvm-tracker] [ScummVM :: Bugs] #17215: ULTIMA4: Enhanced mode crashes after successful melee hits on macOS ARM64

[ScummVM :: Bugs]

#17215: ULTIMA4: Enhanced mode crashes after successful melee hits on macOS ARM64
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Reporter:  davidnir                  |      Owner:  (none)
    Type:  defect                    |     Status:  new
Priority:  normal                    |  Component:  Engine: Ultima
 Version:                            |   Keywords:  crash macos arm64
    Game:  Ultima IV: Quest of the   |  combat enhanced
  Avatar                             |
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 ScummVM crashes during ordinary combat in Ultima IV Enhanced after the
 player successfully hits an enemy with a melee weapon.

 System:

 MacBook with Apple M2 processor

 macOS 15.8 (24H23)

 ARM64 native ScummVM build

 Ultima IV: Quest of the Avatar - Enhanced (DOS/English)

 GOG game files

 Tested versions:

 ScummVM 2026.3.0

 ScummVM 2026.3.1git31808-gb603fb5f8e6, built September 19, 2026

 Both versions exhibit the same problem.

 Steps to reproduce:

 Load the attached save in Ultima IV Enhanced.

 Enter combat with an ordinary enemy such as an orc, skeleton, or troll.

 Attack the enemy repeatedly with a melee weapon.

 After several successful hits, ScummVM crashes completely.

 Additional testing:

 Reproduced using two different saves: an autosave and a manual save.

 Reproduced with both a sword and a mace.

 Passing dozens of turns without attacking did not cause a crash, even when
 the character was eventually killed.

 Attacking an empty adjacent square dozens of times did not cause a crash.

 Setting the SFX volume to zero did not prevent the crash.

 The crash does not necessarily occur on the first successful attack; it
 generally occurs after several blows.

 It does not appear to be associated with killing an enemy.

 Both macOS crash reports show EXC_BAD_ACCESS (SIGSEGV) on the main thread
 while executing inside ScummVM. The stable build attempted to read address
 0x44; the daily build attempted to read address 0x1f8.

 Expected result:
 Successful melee attacks should resolve without crashing ScummVM.

 Actual result:
 After several successful melee hits, the entire ScummVM application
 terminates with EXC_BAD_ACCESS.
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Ticket URL: <https://bugs.scummvm.org/ticket/17215>
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