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[intl] Remove incorrect optimization for 0 length string

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In collator and localeCompare, we have an incorrect optimization
for zero length string that compare the length and ignore the
fact some non zero length string could be considered as equal to
a zero length string because the content are all ignoreable.

Took out this incorrect optimization with test cases.

The regression is introduced in
6fbb8bc806 which first appeared in 97.0.4665.0



Bug: chromium:1347690
Change-Id: Ie70feb9598b1842f8a8744c38f33b3397865abfd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3832526
Reviewed-by: Shu-yu Guo <syg@chromium.org>
Reviewed-by: Jakob Linke <jgruber@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82632}
This commit is contained in:
Frank Tang 2022-08-18 11:20:26 -07:00 committed by V8 LUCI CQ
parent 134ca75cd3
commit ce9b1b2ab0
2 changed files with 21 additions and 5 deletions
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7
src/objects/intl-objects.cc
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@ -230,7 +230,6 @@ icu::StringPiece ToICUStringPiece(Isolate* isolate, Handle<String> string,
if (!flat.IsOneByte()) return icu::StringPiece();
int32_t length = string->length();
DCHECK_LT(offset, length);
const char* char_buffer =
reinterpret_cast<const char*>(flat.ToOneByteVector().begin());
if (!String::IsAscii(char_buffer, length)) {
@ -1418,10 +1417,8 @@ int Intl::CompareStrings(Isolate* isolate, const icu::Collator& icu_collator,
return UCollationResult::UCOL_EQUAL;
}
// Early return for empty strings.
if (string1->length() == 0 || string2->length() == 0) {
return ToUCollationResult(string1->length() - string2->length());
}
// We cannot return early for 0-length strings because of Unicode
// ignorable characters. See also crbug.com/1347690.
string1 = String::Flatten(isolate, string1);
string2 = String::Flatten(isolate, string2);

19
test/intl/regress-1347690.js Normal file
View File

@ -0,0 +1,19 @@
// Copyright 2022 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Comparison to empty string could return zero for certain Unicode character.
// In all locales, some Unicode characters are ignorable.
// Unicode in C0
assertEquals(0, (new Intl.Collator('en')).compare("","\u0001"));
// SOFT HYPHEN
assertEquals(0, (new Intl.Collator('en')).compare("","\u00AD"));
// ARABIC SIGN SAMVAT
assertEquals(0, (new Intl.Collator('en')).compare("","\u0604"));
assertEquals(0, (new Intl.Collator('en')).compare("","\u0001\u0002\u00AD\u0604"));
// Default Thai collation ignores punctuation.
assertEquals(0, (new Intl.Collator('th')).compare(""," "));
assertEquals(0, (new Intl.Collator('th')).compare("","*"));