David T. Lewis uploaded a new version of Kernel to project The Trunk:
http://source.squeak.org/trunk/Kernel-ct.1321.mcz

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

Name: Kernel-ct.1321
Author: ct
Time: 9 April 2020, 7:55:56.724949 pm
UUID: 6f8c6c8d-a379-5f46-b774-587e81ddb067
Ancestors: Kernel-eem.1319

Integrates ModificationForbidden into Error hierarchy. This makes ModificationForbidden catchable by #ifError:, TestResult exError and others. See also: http://forum.world.st/Why-is-ModificationForbidden-not-an-Error-td5114717.html

Further refactorings applied:
- Update class comment (use Smalltalk-typical format, update instvar names and don't hardcode their count)
- Use #translated and #format: for message texts
- Update method comment of #resume which was copied from Context

=============== Diff against Kernel-eem.1319 ===============

Item was changed:
+ Error subclass: #ModificationForbidden
- Exception subclass: #ModificationForbidden
  	instanceVariableNames: 'mirror object fieldIndex newValue retrySelector resumptionValue'
  	classVariableNames: ''
  	poolDictionaries: ''
  	category: 'Kernel-Exceptions'!
  
+ !ModificationForbidden commentStamp: 'ct 4/9/2020 19:49' prior: 0!
+ This error is raised when attempting to mutate a read-only object.
- !ModificationForbidden commentStamp: 'eem 3/11/2020 15:46' prior: 0!
- This exception is raised when attempting to mutate a read-only object.
  
+ My instances describe the necessary state to be able to reproduce the modification via the #retryModification protocol.
- My instances have 5 fields to be able to reproduce the modification via the retryModification method.
  
+ Instance Variables
+ 	mirror:				<Context | Behavior | Array>
+ 	object:				<Object>
+ 	fieldIndex:			<SmallInteger | nil>
+ 	newValue:			<Object>
+ 	resumptionValue:	<Object>
+ 	retrySelector:		<Symbol>
+ 
+ mirror
+ 	- the object that will perform the modification on object if modificationRetried
+ 
+ object
+ 	- read-only object that attempted to mutate
+ 
+ fieldIndex
+ 	- index of the field in the object mutated, relevant for the corresponding selector
+ 
+ newValue
+ 	- value that was attempted to be stored into the read-only object
+ 
+ resumptionValue
+ 	- value that will be returned when the ModificationForbidden is resumed
+ 
+ retrySelector
+ 	- selector that can be used to reproduce the mutation (#object:basicAt:put:, #object:instVarAt:put:, etc.)!
- mirror	<Context|Behavior|Array>	the object that will perform the modification on object if modificationRetried
- object	<Object>					read-only object that attempted to mutate
- index	<SmallInteger | nil>		index of the field in the object mutated, relevant for the corresponding selector
- value	<Object>					value that was attempted to be stored into the read-only object
- selector	<Symbol>					selector that can be used to reproduce the mutation (#object:basicAt:put:, #object:instVarAt:put:, etc)!

Item was removed:
- ----- Method: ModificationForbidden>>defaultAction (in category 'priv handling') -----
- defaultAction
- 	UnhandledError signalForException: self!

Item was changed:
  ----- Method: ModificationForbidden>>indexedMessageText (in category 'printing') -----
  indexedMessageText
+ 
+ 	^ 'Cannot modify field {2} of read-only object {1}' translated
+ 		format: {
+ 			self printObject: object.
+ 			fieldIndex }!
- 	^String streamContents:
- 		[ :s |
- 		s << ' '.
- 		self printObject: object on: s. 
- 		s << ' is read-only, hence its field '.
- 		fieldIndex printOn: s.
- 		s << ' cannot be modified with '.
- 		self printObject: newValue on: s]!

Item was added:
+ ----- Method: ModificationForbidden>>isResumable (in category 'priv handling') -----
+ isResumable
+ 
+ 	^ true!

Item was changed:
  ----- Method: ModificationForbidden>>nonIndexedMessageText (in category 'printing') -----
  nonIndexedMessageText
+ 
+ 	^ 'Cannot execute {2} on read-only object {1}' translated
+ 		format: {
+ 			self printObject: object.
+ 			retrySelector printString }!
- 	^String streamContents:
- 		[ :s |
- 		s << ' '.
- 		self printObject: object on: s. 
- 		s << ' is read-only, hence its selector '.
- 		s << retrySelector.
- 		s << ' cannot be executed with '.
- 		self printObject: newValue on: s]!

Item was added:
+ ----- Method: ModificationForbidden>>printObject: (in category 'private') -----
+ printObject: obj
+ 
+ 	^ [obj printString]
+ 		ifError: ['<cannot print object>' translated]!

Item was removed:
- ----- Method: ModificationForbidden>>printObject:on: (in category 'printing') -----
- printObject: obj on: s
- 	[obj printOn: s]
- 		on: Exception
- 		do: [ :ex | s << '<cannot print object>' ]!

Item was changed:
  ----- Method: ModificationForbidden>>resume (in category 'controlling') -----
  resume
+ 	"Return from the message that signaled the receiver."
- 	"Roll back thisContext to self and resume.  Execute unwind blocks when rolling back.  ASSUMES self is a sender of thisContext"
  
+ 	^ self resume: resumptionValue!
- 	self resume: resumptionValue!