From bc30b17176dca09ec6fdc70c2636a9d0593a6f75 Mon Sep 17 00:00:00 2001
From: Thibaut <thibaut@me.com>
Date: Sun, 10 May 2015 15:52:24 -0400
Subject: [PATCH] Scroll to top on transition cache hit

---
 lib/assets/javascripts/turbolinks.js.coffee  | 15 +++++++------
 test/javascript/turbolinks_visit_test.coffee | 22 ++++++++++++++++++++
 2 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/lib/assets/javascripts/turbolinks.js.coffee b/lib/assets/javascripts/turbolinks.js.coffee
index ac0fbc2c..8f79f785 100644
--- a/lib/assets/javascripts/turbolinks.js.coffee
+++ b/lib/assets/javascripts/turbolinks.js.coffee
@@ -30,12 +30,12 @@ fetch = (url, options = {}) ->
   progressBar?.start()
 
   if transitionCacheEnabled and cachedPage = transitionCacheFor(url.absolute)
-    fetchHistory cachedPage
+    fetchHistory cachedPage, recallScrollPosition: false
     options.showProgressBar = false
-    fetchReplacement url, options
   else
     options.onLoadFunction = resetScrollPosition unless options.change
-    fetchReplacement url, options
+
+  fetchReplacement url, options
 
 transitionCacheFor = (url) ->
   cachedPage = pageCache[url]
@@ -89,11 +89,14 @@ fetchReplacement = (url, options) ->
 
   xhr.send()
 
-fetchHistory = (cachedPage) ->
+fetchHistory = (cachedPage, options) ->
   xhr?.abort()
   changePage createDocument(cachedPage.body), title: cachedPage.title, runScripts: false
   progressBar?.done()
-  recallScrollPosition cachedPage
+  if options.recallScrollPosition
+    recallScrollPosition cachedPage
+  else
+    resetScrollPosition()
   triggerEvent EVENTS.RESTORE
 
 cacheCurrentPage = ->
@@ -587,7 +590,7 @@ onHistoryChange = (event) ->
   if event.state?.turbolinks && event.state.url != currentState.url
     if cachedPage = pageCache[(new ComponentUrl(event.state.url)).absolute]
       cacheCurrentPage()
-      fetchHistory cachedPage
+      fetchHistory cachedPage, recallScrollPosition: true
     else
       visit event.target.location.href
 
diff --git a/test/javascript/turbolinks_visit_test.coffee b/test/javascript/turbolinks_visit_test.coffee
index 06c331ab..4613f239 100644
--- a/test/javascript/turbolinks_visit_test.coffee
+++ b/test/javascript/turbolinks_visit_test.coffee
@@ -259,6 +259,28 @@ suite 'Turbolinks.visit()', ->
     @Turbolinks.pagesCached(0)
     @Turbolinks.visit('iframe2.html')
 
+  test "scrolls to top on transition cache hit", (done) ->
+    load = 0
+    restoreCalled = false
+    @document.addEventListener 'page:load', =>
+      load += 1
+      if load is 1
+        @window.scrollTo(8, 8)
+        setTimeout (=> @Turbolinks.visit('iframe.html')), 0
+      else if load is 2
+        assert.ok restoreCalled
+        assert.equal @window.pageXOffset, 16
+        assert.equal @window.pageYOffset, 16
+        done()
+    @document.addEventListener 'page:restore', =>
+      assert.equal @window.pageXOffset, 0
+      assert.equal @window.pageYOffset, 0
+      @window.scrollTo(16, 16)
+      restoreCalled = true
+    @window.scrollTo(4, 4)
+    @Turbolinks.enableTransitionCache()
+    @Turbolinks.visit('iframe2.html')
+
   test "doesn't scroll to top with :change", (done) ->
     @window.scrollTo(42, 42)
     @document.addEventListener 'page:load', =>