Bug 838954 - Add a newline in .innerHTML serialization of <pre> when first character is a newline. r=smaug

dom/base/nsContentUtils.cpp

@@ -279,6 +279,7 @@ bool nsContentUtils::sEncodeDecodeURLHash = false;
 bool nsContentUtils::sGettersDecodeURLHash = false;
 bool nsContentUtils::sPrivacyResistFingerprinting = false;
 bool nsContentUtils::sSendPerformanceTimingNotifications = false;
+bool nsContentUtils::sAppendLFInSerialization = false;
 
 uint32_t nsContentUtils::sHandlingInputTimeout = 1000;
 
@@ -593,6 +594,8 @@ nsContentUtils::Init()
                                "network.cookie.cookieBehavior",
                                nsICookieService::BEHAVIOR_ACCEPT);
 
+  Preferences::AddBoolVarCache(&sAppendLFInSerialization,
+                               "dom.html_fragment_serialisation.appendLF");
 #if !(defined(DEBUG) || defined(MOZ_ENABLE_JS_DUMP))
   Preferences::AddBoolVarCache(&sDOMWindowDumpEnabled,
                                "browser.dom.window.dump.enabled");
@@ -8979,12 +8982,12 @@ StartElement(Element* aContent, StringBuilder& aBuilder)
 
   aBuilder.Append(">");
 
-  /*
+
   // Per HTML spec we should append one \n if the first child of
   // pre/textarea/listing is a textnode and starts with a \n.
   // But because browsers haven't traditionally had that behavior,
   // we're not changing our behavior either - yet.
-  if (aContent->IsHTMLElement()) {
+  if (nsContentUtils::AppendLFInSerialization() && aContent->IsHTMLElement()) {
     if (localName == nsGkAtoms::pre || localName == nsGkAtoms::textarea ||
         localName == nsGkAtoms::listing) {
       nsIContent* fc = aContent->GetFirstChild();
@@ -8997,7 +9000,7 @@ StartElement(Element* aContent, StringBuilder& aBuilder)
         }
       }
     }
-  }*/
+  }
 }
 
 static inline bool

dom/base/nsContentUtils.h

@@ -1954,6 +1954,10 @@ public:
   static already_AddRefed<mozilla::layers::LayerManager>
   PersistentLayerManagerForDocument(nsIDocument *aDoc);
 
+  /* static */
+  static bool AppendLFInSerialization()
+    { return sAppendLFInSerialization; }
+
   /**
    * Determine whether a content node is focused or not,
    *
@@ -2771,6 +2775,7 @@ private:
   static bool sGettersDecodeURLHash;
   static bool sPrivacyResistFingerprinting;
   static bool sSendPerformanceTimingNotifications;
+  static bool sAppendLFInSerialization;
   static uint32_t sCookiesLifetimePolicy;
   static uint32_t sCookiesBehavior;
 

dom/base/test/test_bug744830.html

@@ -26,7 +26,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=744830
   t.appendChild(document.createElement("textarea"));
   t.firstChild.appendChild(document.createTextNode("\nhello"));
   // This is the old behavior. Spec requires something else.
-  is(t.innerHTML, "<textarea>\nhello</textarea>",
+  is(t.innerHTML, "<textarea>\n\nhello</textarea>",
      "No extra newlines should be inserted to the textarea!");
 
   t.innerHTML = null;

modules/libpref/init/all.js

@@ -5520,3 +5520,9 @@ pref("dom.webkitBlink.filesystem.enabled", true);
 // Is the Servo-backed style system enabled?
 pref("layout.css.servo.enabled", true);
 #endif
+
+#ifdef NIGHTLY_BUILD
+pref("dom.html_fragment_serialisation.appendLF", true);
+#else
+pref("dom.html_fragment_serialisation.appendLF", false);
+#endif

testing/profiles/prefs_general.js

@@ -350,3 +350,4 @@ user_pref("webextensions.tests", true);
 user_pref("startup.homepage_welcome_url", "about:blank");
 user_pref("startup.homepage_welcome_url.additional", "");
 user_pref("browser.usedOnWindows10.introURL", "");
+user_pref("dom.html_fragment_serialisation.appendLF", true);

testing/web-platform/meta/MANIFEST.json

@@ -15341,6 +15341,10 @@
         "path": "domparsing/innerhtml-01.xhtml",
         "url": "/domparsing/innerhtml-01.xhtml"
       },
+      {
+	"path": "domparsing/innerhtml-02.html",
+	"url": "/domparsing/innerhtml-02.html"
+      },
       {
         "path": "domparsing/innerhtml-03.xhtml",
         "url": "/domparsing/innerhtml-03.xhtml"

testing/web-platform/meta/html/syntax/serializing-html-fragments/initial-linefeed-pre.html.ini

@@ -1,8 +0,0 @@
-[initial-linefeed-pre.html]
-  type: testharness
-  [outer div]
-    expected: FAIL
-
-  [inner div]
-    expected: FAIL
-

testing/web-platform/tests/domparsing/innerhtml-02.html

@@ -0,0 +1,126 @@
+<!DOCTYPE html>
+<title>innerHTML in HTML</title>
+<link rel="author" title="Ms2ger" href="mailto:ms2ger@gmail.com">
+<link rel="help" href="http://html5.org/specs/dom-parsing.html#innerhtml">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id="log"></div>
+<script>
+var voidElements = [
+  "area", "base", "basefont", "bgsound", "br", "col", "command", "embed",
+  "frame", "hr", "img", "input", "keygen", "link", "meta", "param", "source",
+  "track", "wbr"
+];
+var tests = [
+  [
+    function() {
+      var el = document.createElement("div");
+      el.appendChild(document.createElement("xmp"))
+        .appendChild(document.createElement("span"))
+        .appendChild(document.createTextNode("<"));
+      return el;
+    },
+    "<xmp><span>&lt;<\/span><\/xmp>"
+  ],
+  [
+    function() {
+      var el = document.createElement("xmp");
+      el.appendChild(document.createElement("span"))
+        .appendChild(document.createTextNode("<"));
+      return el;
+    },
+    "<span>&lt;<\/span>"
+  ],
+  [
+    function() {
+      var el = document.createElement("xmp");
+      el.appendChild(document.createTextNode("<"));
+      return el;
+    },
+    "<"
+  ],
+  [
+    function() {
+      var el = document.createElement("div");
+      el.appendChild(document.createElement("br"));
+      return el;
+    },
+    "<br>"
+  ],
+  [
+    function() {
+      var el = document.createElement("div");
+      el.appendChild(document.createElement("input"))
+        .appendChild(document.createElement("span"));
+      return el;
+    },
+    "<input>"
+  ],
+  [
+    function() {
+      var el = document.createElement("img");
+      el.appendChild(document.createElement("div"))
+        .appendChild(document.createElement("span"));
+      return el.firstChild;
+    },
+    "<span><\/span>"
+  ],
+  [
+    function() {
+      var el = document.createElement("div");
+      el.appendChild(document.createElement("style"))
+        .appendChild(document.createElement("span"));
+      return el;
+    },
+    "<style><span><\/span><\/style>"
+  ],
+  [
+    function() {
+      var el = document.createElement("div");
+      el.appendChild(document.createElement("style"))
+        .appendChild(document.createTextNode("<"));
+      return el;
+    },
+    "<style><<\/style>"
+  ],
+  [
+    function() {
+      var el = document.createElement("div");
+      el.appendChild(document.createElement("style"))
+        .appendChild(document.createElement("span"))
+        .appendChild(document.createTextNode("<"));
+      return el;
+    },
+    "<style><span>&lt;<\/span><\/style>"
+  ]
+];
+voidElements.forEach(function(tag) {
+  tests.push([
+    function() {
+      var el = document.createElement(tag);
+      el.appendChild(document.createElement("span"));
+      return el;
+    },
+    "<span><\/span>"
+  ]);
+});
+["pre", "textarea", "listing"].forEach(function(tag) {
+  tests.push([
+    function() {
+      var el = document.createElement("div");
+      el.appendChild(document.createElement(tag))
+        .appendChild(document.createTextNode("\nA"));
+      return el;
+    },
+    "<" + tag + ">\n\nA<\/" + tag + ">"
+  ]);
+});
+test(function() {
+  tests.forEach(function(t) {
+    var el = t[0](), expected = t[1];
+    test(function() {
+      assert_equals(el.innerHTML, expected);
+    }, "Expected innerHTML: " + format_value(expected) + " for " + el.localName + ".");
+  });
+});
+</script>