Fix GRDynamicVariable>>use:during: in GemStone to correctly implement expected semantics (see method comments for details)

Johan Brichau · Johan Brichau · commit 43c99eb0ea1f · 2017-09-08T09:36:59.000+02:00
diff --git a/repository/Grease-GemStone-Core.package/GRDynamicVariable.class/class/use.during..st b/repository/Grease-GemStone-Core.package/GRDynamicVariable.class/class/use.during..st
@@ -1,11 +1,18 @@
 accessing
 use: anObject during: aBlock
-  | p oldValue result |
-  "We cannot just do a super call to value:during: because the GS implementation does not return a result value and also does not produce an error when the dynamic var was not found."
+  | p hasOldValue oldValue result |
+  "Implementation cannot send a supercall to value:during: because:
+   - this method needs to return the value
+   - the defaultValue may not be invoked here to support throwing errors as defaultValue
+   - nil may not remain installed as the default value once the block has finished running"
   p := Processor activeProcess.
+  hasOldValue := p environment includesKey: self.
   oldValue := p environmentAt: self.
   [ 
   p environmentAt: self put: anObject.
   result := aBlock value ]
-    ensure: [ p environmentAt: self put: oldValue ].
+    ensure: [ 
+      hasOldValue
+        ifFalse: [ p environment removeKey: self ]
+        ifTrue: [ p environmentAt: self put: oldValue ] ].
   ^ result
diff --git a/repository/Grease-GemStone-Core.package/GRDynamicVariable.class/methodProperties.json b/repository/Grease-GemStone-Core.package/GRDynamicVariable.class/methodProperties.json
@@ -2,6 +2,6 @@
 	"class" : {
 		"default" : "JohanBrichau 07/23/2017 09:48",
 		"defaultValue" : "JohanBrichau 07/23/2017 09:47",
-		"use:during:" : "JohanBrichau 09/07/2017 05:38" },
+		"use:during:" : "JB 09/08/2017 00:34" },
 	"instance" : {
 		 } }
diff --git a/repository/Grease-GemStone-Core.package/monticello.meta/version b/repository/Grease-GemStone-Core.package/monticello.meta/version
