Tony Garnock-Jones uploaded a new version of Kernel to project The Trunk:
http://source.squeak.org/trunk/Kernel-tonyg.1152.mcz

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

Name: Kernel-tonyg.1152
Author: tonyg
Time: 11 February 2018, 4:07:32.778194 pm
UUID: 3e6a5937-c9a5-4991-b9d7-c0e023cf75e3
Ancestors: Kernel-tonyg.1151

Clear out Promise rejecters and resolvers once the promise settles - already-fired callbacks will not be needed again, and if not cleared out, hang around forever, causing problems for long-lived, reusable promises.

=============== Diff against Kernel-tonyg.1151 ===============

Item was changed:
  ----- Method: Promise>>rejectWith: (in category 'resolving') -----
  rejectWith: anObject
  	"Reject this promise."
  	mutex critical: [
+ 		(state == #pending) ifTrue: [ | worklist |
- 		(state == #pending) ifTrue: [
  			error := anObject.
  			state := #rejected.
+ 			worklist := rejecters.
+ 			resolvers := #().
+ 			rejecters := #().
+ 			worklist do: [:r | self evaluateRejecter: r]]]!
- 			rejecters do: [:r | self evaluateRejecter: r]]]!

Item was changed:
  ----- Method: Promise>>resolveWith: (in category 'resolving') -----
  resolveWith: arg
  	"Resolve this promise. If arg is itself a Promise, make this promise depend upon it,
  	as detailed in the Promises/A+ spec:
  		https://promisesaplus.com/#the-promise-resolution-procedure"
  
  	arg isPromise
  		ifTrue: [
  			arg whenResolved: [:v | self resolveWith: v].
  			arg whenRejected: [:e | self rejectWith: e]]
  		ifFalse: [
  			mutex critical: [
+ 				(state == #pending) ifTrue: [ | worklist |
- 				(state == #pending) ifTrue: [
  					value := arg.
  					state := #fulfilled.
+ 					worklist := resolvers.
+ 					resolvers = #().
+ 					rejecters := #().
+ 					worklist do: [:r | self evaluateResolver: r]]]]!
- 					resolvers do: [:r | self evaluateResolver: r]]]]!

Item was changed:
  ----- Method: Promise>>whenRejected: (in category 'resolving') -----
  whenRejected: aBlock
  	"Evaluate aBlock when I am rejected"
  	aBlock numArgs <= 1 ifFalse: [self error: 'Must be 0- or 1-argument block'].
+ 	mutex critical: [
+ 		(state == #pending)
+ 			ifTrue: [rejecters := rejecters copyWith: aBlock]
+ 			ifFalse: [self isRejected ifTrue: [self evaluateRejecter: aBlock]]].
+ 	^ nil!
- 	^ mutex critical: [
- 		rejecters := rejecters copyWith: aBlock.
- 		self isRejected ifTrue:[self evaluateRejecter: aBlock].
- 	]!

Item was changed:
  ----- Method: Promise>>whenResolved: (in category 'resolving') -----
  whenResolved: aBlock
  	"Evaluate aBlock when I am resolved"
  	aBlock numArgs <= 1 ifFalse:[self error: 'Must be 0- or 1-argument block'].
+ 	mutex critical: [
+ 		(state == #pending)
+ 			ifTrue: [resolvers := resolvers copyWith: aBlock]
+ 			ifFalse: [self isResolved ifTrue: [self evaluateResolver: aBlock]]].
+ 	^ nil!
- 	^ mutex critical: [
- 		resolvers := resolvers copyWith: aBlock.
- 		self isResolved ifTrue:[self evaluateResolver: aBlock].
- 	]!