From f75b6dc79c232a8287901ffc79d5d0b3a5ff9137 Mon Sep 17 00:00:00 2001
From: Dave Camp <dcamp@mozilla.com>
Date: Mon, 10 Jun 2013 21:18:18 -0700
Subject: [PATCH] Bug 883599 - Fix the inspector actor's nextSibling and
 previousSibling requests. r=paul

---
 toolkit/devtools/server/actors/inspector.js   |  8 +++---
 .../mochitest/test_inspector-traversal.html   | 27 ++++++++++++++++++-
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/toolkit/devtools/server/actors/inspector.js b/toolkit/devtools/server/actors/inspector.js
index 7dc92f7a82a..be0fe43f960 100644
--- a/toolkit/devtools/server/actors/inspector.js
+++ b/toolkit/devtools/server/actors/inspector.js
@@ -567,7 +567,7 @@ let traversalMethod = {
     whatToShow: Option(1)
   },
   response: {
-    node: RetVal("domnode")
+    node: RetVal("domnode", {optional: true})
   }
 }
 
@@ -1035,7 +1035,8 @@ var WalkerActor = protocol.ActorClass({
    */
   nextSibling: method(function(node, options={}) {
     let walker = documentWalker(node.rawNode, options.whatToShow || Ci.nsIDOMNodeFilter.SHOW_ALL);
-    return this._ref(walker.nextSibling());
+    let sibling = walker.nextSibling();
+    return sibling ? this._ref(sibling) : null;
   }, traversalMethod),
 
   /**
@@ -1049,7 +1050,8 @@ var WalkerActor = protocol.ActorClass({
    */
   previousSibling: method(function(node, options={}) {
     let walker = documentWalker(node.rawNode, options.whatToShow || Ci.nsIDOMNodeFilter.SHOW_ALL);
-    return this._ref(walker.previousSibling());
+    let sibling = walker.previousSibling();
+    return sibling ? this._ref(sibling) : null;
   }, traversalMethod),
 
   /**
diff --git a/toolkit/devtools/server/tests/mochitest/test_inspector-traversal.html b/toolkit/devtools/server/tests/mochitest/test_inspector-traversal.html
index fa125c8c86c..fb31388ffa3 100644
--- a/toolkit/devtools/server/tests/mochitest/test_inspector-traversal.html
+++ b/toolkit/devtools/server/tests/mochitest/test_inspector-traversal.html
@@ -185,7 +185,32 @@ addTest(function testSiblings() {
       ok(response.nodes[0] === gWalker.rootNode, "Document element is its own sibling.");
     });
   }).then(runNextTest));
-})
+});
+
+addTest(function testNextSibling() {
+  promiseDone(gWalker.querySelector(gWalker.rootNode, "#y").then(y => {
+    is(y.id, "y", "Got the right node.");
+    return gWalker.nextSibling(y);
+  }).then(z => {
+    is(z.id, "z", "nextSibling got the next node.");
+    return gWalker.nextSibling(z);
+  }).then(nothing => {
+    is(nothing, null, "nextSibling on the last node returned null.");
+  }).then(runNextTest));
+});
+
+addTest(function testPreviousSibling() {
+  promiseDone(gWalker.querySelector(gWalker.rootNode, "#b").then(b => {
+    is(b.id, "b", "Got the right node.");
+    return gWalker.previousSibling(b);
+  }).then(a => {
+    is(a.id, "a", "nextSibling got the next node.");
+    return gWalker.previousSibling(a);
+  }).then(nothing => {
+    is(nothing, null, "previousSibling on the first node returned null.");
+  }).then(runNextTest));
+});
+
 
 addTest(function testFrameTraversal() {
   promiseDone(gWalker.querySelector(gWalker.rootNode, "#childFrame").then(childFrame => {