Close iterator after error in {Map,Set,WeakMap,WeakSet} constructors

Issue #17

5 files changed, 53 insertions, 6 deletions

diff --git a/js/src/builtin/Map.js b/js/src/builtin/Map.js
index 432364614..27a12bfff 100644
--- a/js/src/builtin/Map.js
+++ b/js/src/builtin/Map.js
@@ -40,11 +40,18 @@ function MapConstructorInit(iterable) {
         var nextItem = next.value;
 
         // Step 8.d.
-        if (!IsObject(nextItem))
+        if (!IsObject(nextItem)) {
+            IteratorCloseThrow(iter);
             ThrowTypeError(JSMSG_INVALID_MAP_ITERABLE, "Map");
+        }
 
         // Steps 8.e-j.
-        callContentFunction(adder, map, nextItem[0], nextItem[1]);
+        try {
+            callContentFunction(adder, map, nextItem[0], nextItem[1]);
+        } catch (e) {
+            IteratorCloseThrow(iter);
+            throw e;
+        }
     }
 }
 
diff --git a/js/src/builtin/Set.js b/js/src/builtin/Set.js
index accc70120..c61a49ef8 100644
--- a/js/src/builtin/Set.js
+++ b/js/src/builtin/Set.js
@@ -40,7 +40,12 @@ function SetConstructorInit(iterable) {
         var nextValue = next.value;
 
         // Steps 8.d-e.
-        callContentFunction(adder, set, nextValue);
+        try {
+            callContentFunction(adder, set, nextValue);
+        } catch (e) {
+            IteratorCloseThrow(iter);
+            throw e;
+        }
     }
 }
 
diff --git a/js/src/builtin/Utilities.js b/js/src/builtin/Utilities.js
index bfb1fe7f4..2dece3801 100644
--- a/js/src/builtin/Utilities.js
+++ b/js/src/builtin/Utilities.js
@@ -154,6 +154,29 @@ function GetIterator(obj, method) {
     return iterator;
 }
 
+// ES2017 draft rev 7.4.6.
+// When completion.[[Type]] is throw.
+function IteratorCloseThrow(iter) {
+    // Steps 1-2 (implicit)
+
+    // Step 3.
+    var returnMethod = GetMethod(iter, "return");
+
+    // Step 4 (done in caller).
+    if (returnMethod === undefined)
+        return;
+
+    try {
+        // Step 5.
+        callContentFunction(returnMethod, iter);
+    } catch (e) {
+    }
+
+    // Step 6 (done in caller).
+
+    // Steps 7-9 (skipped).
+}
+
 var _builtinCtorsCache = {__proto__: null};
 
 function GetBuiltinConstructor(builtinName) {
diff --git a/js/src/builtin/WeakMap.js b/js/src/builtin/WeakMap.js
index 066a72bfe..708be8424 100644
--- a/js/src/builtin/WeakMap.js
+++ b/js/src/builtin/WeakMap.js
@@ -40,10 +40,17 @@ function WeakMapConstructorInit(iterable) {
         var nextItem = next.value;
 
         // Step 8.d.
-        if (!IsObject(nextItem))
+        if (!IsObject(nextItem)) {
+            IteratorCloseThrow(iter);
             ThrowTypeError(JSMSG_INVALID_MAP_ITERABLE, "WeakMap");
+        }
 
         // Steps 8.e-j.
-        callContentFunction(adder, map, nextItem[0], nextItem[1]);
+        try {
+            callContentFunction(adder, map, nextItem[0], nextItem[1]);
+        } catch (e) {
+            IteratorCloseThrow(iter);
+            throw e;
+        }
     }
 }
diff --git a/js/src/builtin/WeakSet.js b/js/src/builtin/WeakSet.js
index eb7c2378f..8589f9dc6 100644
--- a/js/src/builtin/WeakSet.js
+++ b/js/src/builtin/WeakSet.js
@@ -40,7 +40,12 @@ function WeakSetConstructorInit(iterable) {
         var nextValue = next.value;
 
         // Steps 8.d-e.
-        callContentFunction(adder, set, nextValue);
+        try {
+            callContentFunction(adder, set, nextValue);
+        } catch (e) {
+            IteratorCloseThrow(iter);
+            throw e;
+        }
     }
 }