[Intl] Call uloc_forLanguageTag before morphing a language tag

The ICU API for maximizing and minimizing a locale ID takes ICU format locale id as an input
so that a BCP 47 language tag must be converted to the corresponding ICU locale id.

Bug: v8:7982
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: I1cb1dacbf057bbc8bb8beb9b62d1ec4becd82624
Reviewed-on: https://chromium-review.googlesource.com/1150934Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Jungshik Shin <jshin@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55768}

src/objects/js-locale.cc

@@ -310,20 +310,37 @@ MaybeHandle<JSLocale> JSLocale::InitializeLocale(Isolate* isolate,
 
 namespace {
 
-Handle<String> MorphLocale(Isolate* isolate, String* input,
+Handle<String> MorphLocale(Isolate* isolate, String* language_tag,
                            int32_t (*morph_func)(const char*, char*, int32_t,
                                                  UErrorCode*)) {
   Factory* factory = isolate->factory();
   char localeBuffer[ULOC_FULLNAME_CAPACITY];
+  char morphBuffer[ULOC_FULLNAME_CAPACITY];
+
   UErrorCode status = U_ZERO_ERROR;
+  // Convert from language id to locale.
+  int32_t parsed_length;
+  int32_t length =
+      uloc_forLanguageTag(language_tag->ToCString().get(), localeBuffer,
+                          ULOC_FULLNAME_CAPACITY, &parsed_length, &status);
+  CHECK(parsed_length == language_tag->length());
+  DCHECK(U_SUCCESS(status));
+  DCHECK_GT(length, 0);
   DCHECK_NOT_NULL(morph_func);
-  int32_t length = (*morph_func)(input->ToCString().get(), localeBuffer,
-                                 ULOC_FULLNAME_CAPACITY, &status);
+  // Add the likely subtags or Minimize the subtags on the locale id
+  length =
+      (*morph_func)(localeBuffer, morphBuffer, ULOC_FULLNAME_CAPACITY, &status);
   DCHECK(U_SUCCESS(status));
   DCHECK_GT(length, 0);
-  std::string locale(localeBuffer, length);
-  std::replace(locale.begin(), locale.end(), '_', '-');
-  return factory->NewStringFromAsciiChecked(locale.c_str());
+  // Returns a well-formed language tag
+  length = uloc_toLanguageTag(morphBuffer, localeBuffer, ULOC_FULLNAME_CAPACITY,
+                              false, &status);
+  DCHECK(U_SUCCESS(status));
+  DCHECK_GT(length, 0);
+  std::string lang(localeBuffer, length);
+  std::replace(lang.begin(), lang.end(), '_', '-');
+
+  return factory->NewStringFromAsciiChecked(lang.c_str());
 }
 
 }  // namespace

test/intl/regress-7982.js

+// Copyright 2018 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.
+
+// Flags: --harmony-locale
+
+// Make sure that maximize and minimize of locales work reasonbly.
+
+assertEquals("zh-Hans-CN-u-ca-chinese", new Intl.Locale("zh-u-ca-Chinese").maximize().toString());
+assertEquals("zh-u-ca-chinese", new Intl.Locale("zh-u-ca-Chinese").minimize().toString());
+assertEquals("th-Thai-TH-u-nu-thai", new Intl.Locale("th-Thai-TH-u-nu-Thai").maximize().toString());
+assertEquals("th-u-nu-thai", new Intl.Locale("th-Thai-TH-u-nu-Thai").minimize().toString());
+assertEquals("th-Thai-TH-u-nu-thai", new Intl.Locale("th-u-nu-Thai").maximize().toString());
+assertEquals("th-u-nu-thai", new Intl.Locale("th-u-nu-Thai").minimize().toString());
+assertEquals("zh-Hans-CN-u-ca-chinese", new Intl.Locale("zh-CN-u-ca-chinese").maximize().toString());
+assertEquals("zh-u-ca-chinese", new Intl.Locale("zh-CN-u-ca-chinese").minimize().toString());
+assertEquals("zh-Hant-TW-u-ca-chinese", new Intl.Locale("zh-TW-u-ca-chinese").maximize().toString());
+assertEquals("zh-TW-u-ca-chinese", new Intl.Locale("zh-TW-u-ca-chinese").minimize().toString());
+assertEquals("zh-Hant-HK-u-ca-chinese", new Intl.Locale("zh-HK-u-ca-chinese").maximize().toString());
+assertEquals("zh-HK-u-ca-chinese", new Intl.Locale("zh-HK-u-ca-chinese").minimize().toString());
+assertEquals("zh-Hant-TW-u-ca-chinese", new Intl.Locale("zh-Hant-u-ca-chinese").maximize().toString());
+assertEquals("zh-Hant-u-ca-chinese", new Intl.Locale("zh-Hant-u-ca-chinese").minimize().toString());
+assertEquals("zh-Hans-CN-u-ca-chinese", new Intl.Locale("zh-Hans-u-ca-chinese").maximize().toString());
+assertEquals("zh-u-ca-chinese", new Intl.Locale("zh-Hans-u-ca-chinese").minimize().toString());
+assertEquals("zh-Hant-CN-u-ca-chinese", new Intl.Locale("zh-Hant-CN-u-ca-chinese").maximize().toString());
+assertEquals("zh-Hant-CN-u-ca-chinese", new Intl.Locale("zh-Hant-CN-u-ca-chinese").minimize().toString());
+assertEquals("zh-Hans-CN-u-ca-chinese", new Intl.Locale("zh-Hans-CN-u-ca-chinese").maximize().toString());
+assertEquals("zh-u-ca-chinese", new Intl.Locale("zh-Hans-CN-u-ca-chinese").minimize().toString());
+assertEquals("zh-Hant-TW-u-ca-chinese", new Intl.Locale("zh-Hant-TW-u-ca-chinese").maximize().toString());
+assertEquals("zh-TW-u-ca-chinese", new Intl.Locale("zh-Hant-TW-u-ca-chinese").minimize().toString());
+assertEquals("zh-Hans-TW-u-ca-chinese", new Intl.Locale("zh-Hans-TW-u-ca-chinese").maximize().toString());
+assertEquals("zh-Hans-TW-u-ca-chinese", new Intl.Locale("zh-Hans-TW-u-ca-chinese").minimize().toString());
+assertEquals("zh-Hant-HK-u-ca-chinese", new Intl.Locale("zh-Hant-HK-u-ca-chinese").maximize().toString());
+assertEquals("zh-HK-u-ca-chinese", new Intl.Locale("zh-Hant-HK-u-ca-chinese").minimize().toString());
+assertEquals("zh-Hans-HK-u-ca-chinese", new Intl.Locale("zh-Hans-HK-u-ca-chinese").maximize().toString());
+assertEquals("zh-Hans-HK-u-ca-chinese", new Intl.Locale("zh-Hans-HK-u-ca-chinese").minimize().toString());