[JSC] implement spec changes for String#padStart and String#padEnd

https://bugs.webkit.org/show_bug.cgi?id=157139

Reviewed by Keith Miller.

Previously, if the fill string was the empty string, it was treated as a
single U+0020 SPACE character. Now, if this occurs, the original string
is returned instead.

Change was discussed at TC39 in March [1], and is reflected in new
test262 tests for the feature.

[1] https://github.com/tc39/tc39-notes/blob/master/es7/2016-03/march-29.md#stringprototypepadstartpadend

* runtime/StringPrototype.cpp:
(JSC::padString):
* tests/es6/String.prototype_methods_String.prototype.padEnd.js:
(TestFillerToString):
(TestFillerEmptyString):
* tests/es6/String.prototype_methods_String.prototype.padStart.js:
(TestFillerToString):
(TestFillerEmptyString):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@200194 268f45cc-cd09-0410-ab3c-d52691b4dbfc

diff --git a/Source/JavaScriptCore/ChangeLog b/Source/JavaScriptCore/ChangeLog
index 9a78c7d..0929d93 100644 (file)
--- a/Source/JavaScriptCore/ChangeLog
+++ b/Source/JavaScriptCore/ChangeLog
@@ -1,3 +1,28 @@
+2016-04-28  Caitlin Potter  <caitp@igalia.com>
+
+        [JSC] implement spec changes for String#padStart and String#padEnd
+        https://bugs.webkit.org/show_bug.cgi?id=157139
+
+        Reviewed by Keith Miller.
+
+        Previously, if the fill string was the empty string, it was treated as a
+        single U+0020 SPACE character. Now, if this occurs, the original string
+        is returned instead.
+
+        Change was discussed at TC39 in March [1], and is reflected in new
+        test262 tests for the feature.
+
+        [1] https://github.com/tc39/tc39-notes/blob/master/es7/2016-03/march-29.md#stringprototypepadstartpadend
+
+        * runtime/StringPrototype.cpp:
+        (JSC::padString):
+        * tests/es6/String.prototype_methods_String.prototype.padEnd.js:
+        (TestFillerToString):
+        (TestFillerEmptyString):
+        * tests/es6/String.prototype_methods_String.prototype.padStart.js:
+        (TestFillerToString):
+        (TestFillerEmptyString):
+
 2016-04-28  Skachkov Oleksandr  <gskachkov@gmail.com>
 
         Crash for non-static super property call in derived class constructor

diff --git a/Source/JavaScriptCore/runtime/StringPrototype.cpp b/Source/JavaScriptCore/runtime/StringPrototype.cpp
index cf973de..89c1e8a 100644 (file)
--- a/Source/JavaScriptCore/runtime/StringPrototype.cpp
+++ b/Source/JavaScriptCore/runtime/StringPrototype.cpp
@@ -851,6 +851,8 @@ static EncodedJSValue padString(ExecState& exec, StringPaddingLocation paddingLo
         filler = fillString.toString(&exec);
         if (!filler)
             return JSValue::encode(jsUndefined());
+        if (!filler->length())
+            return JSValue::encode(thisString);
     }
 
     unsigned fillLength = static_cast<unsigned>(maxLength) - thisString->length();
@@ -861,7 +863,7 @@ static EncodedJSValue padString(ExecState& exec, StringPaddingLocation paddingLo
             return JSValue::encode(throwOutOfMemoryError(&exec));
     }
 
-    if (!filler || filler->length() <= 1) {
+    if (!filler || filler->length() == 1) {
         UChar character = filler && filler->length() ? filler->view(&exec)[0] : ' ';
         if (!(character & ~0xff))
             filler = repeatCharacter(exec, static_cast<LChar>(character), fillLength);

diff --git a/Source/JavaScriptCore/tests/es6/String.prototype_methods_String.prototype.padEnd.js b/Source/JavaScriptCore/tests/es6/String.prototype_methods_String.prototype.padEnd.js
index 2ccdabd..41242bb 100644 (file)
--- a/Source/JavaScriptCore/tests/es6/String.prototype_methods_String.prototype.padEnd.js
+++ b/Source/JavaScriptCore/tests/es6/String.prototype_methods_String.prototype.padEnd.js
@@ -77,10 +77,17 @@ function shouldThrow(func, errorType) {
 (function TestFillerToString() {
     shouldBe(".         ", ".".padEnd(10));
     shouldBe(".         ", ".".padEnd(10, undefined));
-    shouldBe(".         ", ".".padEnd(10, { toString() { return ""; } }));
+    shouldBe(".XXXXXXXXX", ".".padEnd(10, { toString() { return "X"; } }));
+    shouldBe(".111111111", ".".padEnd(10, { toString: undefined, valueOf() { return 1; } }));
     shouldBe(".nullnulln", ".".padEnd(10, null));
 })();
 
+(function TestFillerEmptyString() {
+    shouldBe(".", ".".padEnd(10000, ""));
+    shouldBe(".", ".".padEnd(10000, { toString() { return ""; } }));
+    shouldBe(".", ".".padEnd(10000, { toString: undefined, valueOf() { return ""; } }));
+})();
+
 (function TestSingleCharacterFiller() {
     shouldBe(".!!!!!!!!!", ".".padEnd(10, "!"));
     shouldBe(".!!!!!!!!!", ".".padEnd(10, { toString() { return "!"; } }));

diff --git a/Source/JavaScriptCore/tests/es6/String.prototype_methods_String.prototype.padStart.js b/Source/JavaScriptCore/tests/es6/String.prototype_methods_String.prototype.padStart.js
index 17dc269..7085baf 100644 (file)
--- a/Source/JavaScriptCore/tests/es6/String.prototype_methods_String.prototype.padStart.js
+++ b/Source/JavaScriptCore/tests/es6/String.prototype_methods_String.prototype.padStart.js
@@ -77,10 +77,17 @@ function shouldThrow(func, errorType) {
 (function TestFillerToString() {
     shouldBe("         .", ".".padStart(10));
     shouldBe("         .", ".".padStart(10, undefined));
-    shouldBe("         .", ".".padStart(10, { toString() { return ""; } }));
+    shouldBe("XXXXXXXXX.", ".".padStart(10, { toString() { return "X"; } }));
+    shouldBe("111111111.", ".".padStart(10, { toString: undefined, valueOf() { return 1; } }));
     shouldBe("nullnulln.", ".".padStart(10, null));
 })();
 
+(function TestFillerEmptyString() {
+    shouldBe(".", ".".padStart(10000, ""));
+    shouldBe(".", ".".padStart(10000, { toString() { return ""; } }));
+    shouldBe(".", ".".padStart(10000, { toString: undefined, valueOf() { return ""; } }));
+})();
+
 (function TestSingleCharacterFiller() {
     shouldBe("!!!!!!!!!.", ".".padStart(10, "!"));
     shouldBe("!!!!!!!!!.", ".".padStart(10, { toString() { return "!"; } }));