[[ Bug 21333 ]] Allow aggregates to contain nullptrs

livecodeali · livecodeali · commit 9198210498f7 · 2018-06-05T15:17:35.000+01:00
diff --git a/docs/lcb/notes/feature-nullable_aggregate_fields.md b/docs/lcb/notes/feature-nullable_aggregate_fields.md
@@ -0,0 +1,4 @@
+# LiveCode Builder Language
+## Nullable aggregate fields
+* Aggregate fields of Pointer type can now contain `nothing`, 
+  i.e. null pointers
diff --git a/libfoundation/src/foundation-foreign.cpp b/libfoundation/src/foundation-foreign.cpp
@@ -1294,9 +1294,16 @@ static bool _aggregate_export(const MCForeignTypeDescriptor* desc, MCValueRef p_
             const MCForeignTypeDescriptor *t_field_desc = MCForeignTypeInfoGetDescriptor(t_field_type);
             if (t_element_type == t_field_desc->bridgetype)
             {
-                if (!t_field_desc->doexport(t_field_desc, t_element, false, t_ptr))
+                if (t_element_type == kMCNullTypeInfo)
                 {
-                    t_success = false;
+                     MCMemoryClear(t_ptr, t_size);
+                }
+                else
+                {
+                    if (!t_field_desc->doexport(t_field_desc, t_element, false, t_ptr))
+                    {
+                        t_success = false;
+                    }
                 }
             }
             else if (MCTypeInfoIsForeign(t_element_type))
diff --git a/tests/lcb/vm/foreign-aggregate.lcb b/tests/lcb/vm/foreign-aggregate.lcb
@@ -26,4 +26,18 @@ public handler TestForeignAggregate_Roundtrip()
 	end repeat
 end handler
 
+public foreign type AggregateWithPointer binds to "MCAggregateTypeInfo:r"
+constant kAggregateWithNullPointer is [nothing]
+
+public handler TestForeignAggregateNullPointerRoundTrip()
+	variable tAggregate as AggregateWithPointer
+	put kAggregateWithNullPointer into tAggregate
+	
+	variable tList as List
+	put tAggregate into tList
+	
+	test "aggregate containing null pointer roundtrips" when \
+		tList[1] is kAggregateWithNullPointer[1]
+end handler
+
 end module

Original file line number	Diff line number	Diff line change
`@@ -1294,9 +1294,16 @@ static bool _aggregate_export(const MCForeignTypeDescriptor* desc, MCValueRef p_`
`1294`	`1294`	`const MCForeignTypeDescriptor *t_field_desc = MCForeignTypeInfoGetDescriptor(t_field_type);`
`1295`	`1295`	`if (t_element_type == t_field_desc->bridgetype)`
`1296`	`1296`	`{`
`1297`		`- if (!t_field_desc->doexport(t_field_desc, t_element, false, t_ptr))`
	`1297`	`+ if (t_element_type == kMCNullTypeInfo)`
`1298`	`1298`	`{`
`1299`		`- t_success = false;`
	`1299`	`+ MCMemoryClear(t_ptr, t_size);`
	`1300`	`+ }`
	`1301`	`+ else`
	`1302`	`+ {`
	`1303`	`+ if (!t_field_desc->doexport(t_field_desc, t_element, false, t_ptr))`
	`1304`	`+ {`
	`1305`	`+ t_success = false;`
	`1306`	`+ }`
`1300`	`1307`	`}`
`1301`	`1308`	`}`
`1302`	`1309`	`else if (MCTypeInfoIsForeign(t_element_type))`