Bug 1099103 - Prevent numbers input using a grouping separator from being mis-processed as if the separator was a decimal separator. r=dholbert

dom/html/test/forms/test_input_number_data.js

@@ -30,3 +30,8 @@ var tests = [
     inputWithoutGrouping: "123456.78", value: 123456.78
   },
 ];
+
+var invalidTests = [
+  { desc: "Invalid German", langTag: "de", input: "12.34" }
+];
+

dom/html/test/forms/test_input_number_l10n.html

@@ -49,11 +49,24 @@ function runTest(test) {
                                      "') localization without grouping separator");
 }
 
+function runInvalidInputTest(test) {
+  elem.lang = test.langTag;
+  elem.value = 0;
+  elem.focus();
+  elem.select();
+  sendString(test.input);
+  is(elem.value, "", "Test " + test.desc + " ('" + test.langTag +
+                             "') with invalid input: " + test.input);
+}
+
 function startTests() {
   elem = document.getElementById("input");
   for (var test of tests) {
     runTest(test, elem);
   }
+  for (var test of invalidTests) {
+    runInvalidInputTest(test, elem);
+  }
 }
 
 </script>

dom/html/test/forms/test_input_number_validation.html

@@ -57,11 +57,26 @@ function runTest(test) {
   checkIsInvalid(elem, `${desc} without grouping separator`);
 }
 
+function runInvalidInputTest(test) {
+  elem.lang = test.langTag;
+
+  gInvalid = false; // reset
+  var desc = `${test.desc}  (lang='${test.langTag}', id='${elem.id}')`;
+  elem.value = 0;
+  elem.focus();
+  elem.select();
+  sendString(test.input);
+  checkIsInvalid(elem, `${desc} with invalid input`);
+}
+
 function startTests() {
   elem = document.getElementById("input");
   for (var test of tests) {
     runTest(test);
   }
+  for (var test of invalidTests) {
+    runInvalidInputTest(test);
+  }
   elem = document.getElementById("requiredinput");
   for (var test of tests) {
     runTest(test);

layout/forms/nsNumberControlFrame.cpp

@@ -776,46 +776,40 @@ nsNumberControlFrame::GetValueOfAnonTextControl(nsAString& aValue)
   //
   //   http://www.whatwg.org/specs/web-apps/current-work/multipage/common-microsyntaxes.html#floating-point-numbers
   //
-  // so that it can be parsed by functions like HTMLInputElement::
-  // StringToDecimal (the HTML-5-conforming parsing function) which don't know
-  // how to handle numbers that are formatted differently (for example, with
-  // non-ASCII digits, with grouping separator characters or with a decimal
-  // separator character other than '.').
-  //
-  // We need to be careful to avoid normalizing numbers that are already
-  // formatted for a locale that matches the format of HTML 5's "valid
-  // floating-point number" and have no grouping separator characters. (In
-  // other words we want to return the number as specified by the user, not the
-  // de-localized serialization, since the latter will normalize the value.)
-  // For example, if the user's locale is English and the user types in "2e2"
-  // then inputElement.value should be "2e2" and not "100". This is because
-  // content (and tests) expect us to avoid "normalizing" the number that the
-  // user types in if it's not necessary in order to make sure it conforms to
-  // HTML 5's "valid floating-point number" format.
-  //
-  // Note that we also need to be careful when trying to avoid normalization.
-  // For example, just because "1.234" _looks_ like a valid floating-point
-  // number according to the spec does not mean that it should be returned
-  // as-is. If the user's locale is German, then this represents the value
-  // 1234, not 1.234, so it still needs to be de-localized. Alternatively, if
-  // the user's locale is English and they type in "1,234" we _do_ need to
-  // normalize the number to "1234" because HTML 5's valid floating-point
-  // number format does not allow the ',' grouping separator. We can detect all
-  // the cases where we need to convert by seeing if the locale-specific
-  // parsing function understands the user input to mean the same thing as the
-  // HTML-5-conforming parsing function. If so, then we should return the value
-  // as-is to avoid normalization. Otherwise, we return the de-localized
-  // serialization.
+  // This is necessary to allow the number that we return to be parsed by
+  // functions like HTMLInputElement::StringToDecimal (the HTML-5-conforming
+  // parsing function) which don't know how to handle numbers that are
+  // formatted differently (for example, with non-ASCII digits, with grouping
+  // separator characters or with a decimal separator character other than
+  // '.').
+
   ICUUtils::LanguageTagIterForContent langTagIter(mContent);
   double value = ICUUtils::ParseNumber(aValue, langTagIter);
-  if (IsFinite(value) &&
-      value != HTMLInputElement::StringToDecimal(aValue).toDouble()) {
+  if (!IsFinite(value)) {
     aValue.Truncate();
-    aValue.AppendFloat(value);
+    return;
   }
+  if (value == HTMLInputElement::StringToDecimal(aValue).toDouble()) {
+    // We want to preserve the formatting of the number as typed in by the user
+    // whenever possible. Since the localized serialization parses to the same
+    // number as the de-localized serialization, we can do that. This helps
+    // prevent normalization of input such as "2e2" (which would otherwise be
+    // converted to "200"). Content relies on this.
+    //
+    // Typically we will only get here for locales in which numbers are
+    // formatted in the same way as they are for HTML5's "valid floating-point
+    // number" format.
+    return;
+  }
+  // We can't preserve the formatting, otherwise functions such as
+  // HTMLInputElement::StringToDecimal would incorrectly process the number
+  // input by the user. For example, "12.345" with lang=de de-localizes as
+  // 12345, but HTMLInputElement::StringToDecimal would mistakenly parse it as
+  // 12.345. Another example would be "12,345" with lang=de which de-localizes
+  // as 12.345, but HTMLInputElement::StringToDecimal would parse it to NaN.
+  aValue.Truncate();
+  aValue.AppendFloat(value);
 #endif
-  // else, we return whatever FromContent put into aValue (the number as typed
-  // in by the user)
 }
 
 bool