From fa239ea2705b97571adb68e26f710e89d877b686 Mon Sep 17 00:00:00 2001
From: Tim Abbott <tabbott@humbughq.com>
Date: Wed, 3 Apr 2013 14:44:26 -0400
Subject: [PATCH] hashchange: Don't change the hash when called from hashchange
 code.

I generally don't like this sort of state variable, but I don't see a
better solution.  The codepath is that when you start out on the
subscriptions page and then click one of the left sidebar links to
narrow to something:

(1) hashchanged() would call ui.change_tab
(2) ui.change_tab triggers a gear change event
(3) The ui.js gear-changed event handler updates the hash

Resulting in the hash ending up at "#".  Since there's no easy way to
pass arguments through to the event handler, we just use a global
variable inside hash_change.js to track whether we're currently
handling a hashchange event.

(imported from commit 7bb905a223b5539240fc36de7896ee8074ebc62e)
---
 zephyr/static/js/hashchange.js | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/zephyr/static/js/hashchange.js b/zephyr/static/js/hashchange.js
index 7e4bf29640..3319207d32 100644
--- a/zephyr/static/js/hashchange.js
+++ b/zephyr/static/js/hashchange.js
@@ -3,6 +3,7 @@ var hashchange = (function () {
 var exports = {};
 
 var expected_hash = false;
+var changing_hash = false;
 
 // Some browsers zealously URI-decode the contents of
 // window.location.hash.  So we hide our URI-encoding
@@ -19,6 +20,9 @@ function decodeHashComponent(str) {
 }
 
 exports.changehash = function (newhash) {
+    if (changing_hash) {
+        return;
+    }
     expected_hash = newhash;
     // Some browsers reset scrollTop when changing the hash to "",
     // so we save and restore it.
@@ -32,6 +36,9 @@ exports.changehash = function (newhash) {
 };
 
 exports.save_narrow = function (operators) {
+    if (changing_hash) {
+        return;
+    }
     if (operators === undefined) {
         exports.changehash('#');
     } else {
@@ -60,7 +67,7 @@ function parse_narrow(hash) {
 }
 
 // Returns true if this function performed a narrow
-function hashchanged() {
+function do_hashchange() {
     // If window.location.hash changed because our app explicitly
     // changed it, then we don't need to do anything.
     // (This function only neds to jump into action if it changed
@@ -95,6 +102,13 @@ function hashchanged() {
     return false;
 }
 
+function hashchanged() {
+    changing_hash = true;
+    var ret = do_hashchange();
+    changing_hash = false;
+    return ret;
+}
+
 exports.initialize = function () {
     window.onhashchange = hashchanged;
     if (hashchanged()) {