Bug 1216261 - Fix OOM handling of DebugScopes. (r=jonco)

js/src/jit-test/tests/debug/bug1216261.js

@@ -0,0 +1,15 @@
+// |jit-test| exitstatus: 3
+
+if (!('oomAfterAllocations' in this))
+    quit(3);
+
+var g = newGlobal();
+var dbg = new Debugger(g);
+dbg.onDebuggerStatement = function(frame) {
+    oomAfterAllocations(5);
+    // OOMs here, and possibly again in the error reporter when trying to
+    // report the OOM, so the shell just exits with code 3.
+    frame.older.eval("escaped = function() { return y }");
+}
+g.eval("function h() { debugger }");
+g.eval("(function () { var y = {p:42}; h(); yield })().next();");

js/src/vm/ScopeObject.cpp

@@ -2354,7 +2354,7 @@ DebugScopes::DebugScopes(JSContext* cx)
 
 DebugScopes::~DebugScopes()
 {
-    MOZ_ASSERT(missingScopes.empty());
+    MOZ_ASSERT_IF(missingScopes.initialized(), missingScopes.empty());
 }
 
 bool
@@ -2454,15 +2454,14 @@ DebugScopes::ensureCompartmentData(JSContext* cx)
     if (c->debugScopes)
         return c->debugScopes;
 
-    c->debugScopes = cx->runtime()->new_<DebugScopes>(cx);
-    if (c->debugScopes && c->debugScopes->init())
-        return c->debugScopes;
+    AutoInitGCManagedObject<DebugScopes> debugScopes(cx->make_unique<DebugScopes>(cx));
+    if (!debugScopes || !debugScopes->init()) {
+        ReportOutOfMemory(cx);
+        return nullptr;
+    }
 
-    if (c->debugScopes)
-        js_delete<DebugScopes>(c->debugScopes);
-    c->debugScopes = nullptr;
-    ReportOutOfMemory(cx);
-    return nullptr;
+    c->debugScopes = debugScopes.release();
+    return c->debugScopes;
 }
 
 DebugScopeObject*