Chris Muller uploaded a new version of System to project The Trunk:
http://source.squeak.org/trunk/System-cmm.1368.mcz

==================== Summary ====================

Name: System-cmm.1368
Author: cmm
Time: 7 September 2022, 11:44:24.530988 pm
UUID: 1e9cce91-389c-4e8f-9fb2-05714f748ca4
Ancestors: System-ct.1367

When Squeak is run headless with a syntax error in the startup document, report it to the terminal and exit rather than leave the process hung with no output clues.

=============== Diff against System-ct.1367 ===============

Item was changed:
  ----- Method: CodeLoader>>installSourceFile: (in category 'installing') -----
  installSourceFile: aStream
  	"Install the previously loaded source file"
  	| contents trusted |
  	aStream ifNil:[^self error:'No content to install'].
  	trusted := SecurityManager default positionToSecureContentsOf: aStream.
  	trusted ifFalse:[(SecurityManager default enterRestrictedMode) 
  					ifFalse:[ aStream close.
  							^ self error:'Insecure content encountered']].
  	contents := self allButShebangLine: aStream upToEnd unzipped asString.
  	(aStream respondsTo: #close) ifTrue:[aStream close].
+ 	^[contents readStream fileIn] 
+ 		on: SyntaxErrorNotification 
+ 		do: [ : err | Smalltalk isHeadless
+ 			 ifTrue: 
+ 				[FileStream stdout nextPutAll: err errorCode; cr; flush.
+ 				Smalltalk snapshot: false andQuit: true ]
+ 			ifFalse: [err pass] ]!
- 	^contents readStream fileIn!