Add support for resetting the env namespace

src/Pact/Native.hs

@@ -553,9 +553,18 @@ namespaceDef = setTopLevelOnly $ defGasRNative "namespace" namespace
   where
     namespace :: GasRNativeFun e
     namespace g i as = case as of
-      [TLitString nsn] -> go g i nsn
+      [TLitString nsn] ->
+        ifExecutionFlagSet FlagDisablePact47
+          (go g i nsn)
+          (if T.null nsn then
+             goEmpty g i
+           else go g i nsn)
       _ -> argsError i as
 
+    goEmpty g0 fa = computeGas' g0 fa (GUnreduced [])
+      $ success "Namespace reset to root"
+      $ evalRefs . rsNamespace .= Nothing
+
     go g0 fa ns = do
       let name = NamespaceName ns
           info = _faInfo fa

tests/pact/namespaces.repl

@@ -291,3 +291,29 @@
 
 
 (rollback-tx)
+
+(begin-tx)
+
+(env-exec-config ['DisablePact47])
+(namespace 'carl)
+
+(expect-failure
+  "Setting namespace back to root namespace pre-Pact 4.7 fork fails"
+  (namespace ""))
+
+(expect
+  "Carl contract fqn not required for member access - no ns"
+  true
+  (carl-module.f))
+
+(env-exec-config [])
+
+(expect
+  "Setting namespace back to root namespace post-Pact 4.7 fork succeeds"
+  "Namespace reset to root"
+  (namespace ""))
+
+(expect
+  "Carl contract fqn required for member access - with ns"
+  true
+  (carl.carl-module.f))