Faulty code: make undeclared write resumable with the right value

src/Kernel-Tests-Extended/CompiledMethodTest.class.st

@@ -1003,6 +1003,38 @@ CompiledMethodTest >> testWritesSlot [
 	self assert: ((Point>>#setX:setY:) writesSlot: (Point slotNamed: #x))
 ]
 
+{ #category : #'tests - testing' }
+CompiledMethodTest >> testWritesUndeclared [
+	| method |
+
+	"x is an ivar"
+	method := self class compiler compile: 'x ^ x := 0'.
+	self deny: method usesUndeclareds.
+	self assert: (self executeMethod: method) equals: 0.
+
+	"undeclaredxyz is not declared"
+	method := self class compiler permitFaulty: true; compile: 'z ^ undeclaredxyz := 1'.
+	self assert: method usesUndeclareds.
+	self should: [ self executeMethod: method ] raise: UndeclaredVariableWrite.
+	self
+		assert:
+			([ self executeMethod: method ]
+				on: UndeclaredVariableWrite
+				do: [:e | e resume])
+		equals: 1.
+
+	"check same behavior in blocks"
+	method := self class compiler permitFaulty: true; compile: 'msg ^ self in: [ :anObject | undeclaredxyz := 2 ]'.
+	self assert: method usesUndeclareds.
+	self should: [ self executeMethod: method ] raise: UndeclaredVariableWrite.
+	self
+		assert:
+			([ self executeMethod: method ]
+				on: UndeclaredVariableWrite
+				do: [:e | e resume])
+		equals: 2
+]
+
 { #category : #examples }
 CompiledMethodTest >> writeX [
 

src/Kernel/UndeclaredVariable.class.st

@@ -83,9 +83,10 @@ UndeclaredVariable >> register [
 UndeclaredVariable >> runtimeUndeclaredWrite: anObject [
 
 	<debuggerCompleteToSender>
-	UndeclaredVariableWrite new
+	^ UndeclaredVariableWrite new
 		messageText: 'Attempt to write to undeclared variable ' , self name;
 		variable: self;
+		value: anObject;
 		signal
 ]
 

src/Kernel/UndeclaredVariableWrite.class.st

@@ -5,11 +5,37 @@ Class {
 	#name : #UndeclaredVariableWrite,
 	#superclass : #Error,
 	#instVars : [
-		'variable'
+		'variable',
+		'value'
 	],
 	#category : #'Kernel-Exceptions'
 }
 
+{ #category : #testing }
+UndeclaredVariableWrite >> defaultResumeValue [
+
+	^ value
+]
+
+{ #category : #testing }
+UndeclaredVariableWrite >> isResumable [
+	"The undeclared variable write become a no-op"
+
+	^ true
+]
+
+{ #category : #accessing }
+UndeclaredVariableWrite >> value [
+
+	^ value
+]
+
+{ #category : #accessing }
+UndeclaredVariableWrite >> value: anObject [
+
+	value := anObject
+]
+
 { #category : #accessing }
 UndeclaredVariableWrite >> variable [