bug #40162 [Intl] fix Locale::getFallback() throwing exception on lon…

…g $locale (AmirHo3ein13)

This PR was squashed before being merged into the 4.4 branch.

Discussion
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[Intl] fix Locale::getFallback() throwing exception on long $locale

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix #39100
| License       | MIT
| Doc PR        |

`Locale::getFallback()` throws an exception when the `$locale` length is greater than `INTL_MAX_LOCALE_LEN` so I added a condition to check if locale_parse return null, the `Locale::getFallback()` don't call `\count` function and just return null instead.

Commits
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a89ced8 [Intl] fix Locale::getFallback() throwing exception on long $locale

src/Symfony/Component/Intl/Locale.php

@@ -68,7 +68,8 @@ public static function getDefaultFallback(): ?string
     public static function getFallback(string $locale): ?string
     {
         if (\function_exists('locale_parse')) {
-            $localeSubTags = locale_parse($locale);
+            $localeSubTags = locale_parse($locale) ?? ['language' => $locale];
+
             if (1 === \count($localeSubTags)) {
                 if ('root' !== self::$defaultFallback && self::$defaultFallback === $localeSubTags['language']) {
                     return 'root';

src/Symfony/Component/Intl/Tests/LocaleTest.php

@@ -70,4 +70,16 @@ public function testDefaultRootFallback()
 
         Locale::setDefaultFallback($prev);
     }
+
+    /**
+     * @requires function locale_parse
+     */
+    public function testLongLocaleFallback()
+    {
+        $locale = 'LC_TYPE=fr_FR.UTF-8;LC_NUMERIC=C;LC_TIME=fr_FR.UTF-8;LC_COLLATE=fr_FR.UTF-8;'.
+            'LC_MONETARY=fr_FR.UTF-8;LC_MESSAGES=fr_FR.UTF-8;LC_PAPER=fr_FR.UTF-8;LC_NAME=fr_FR.UTF-8;'.
+            'LC_ADDRESS=fr_FR.UTF-8;LC_TELEPHONE=fr_FR.UTF-8;LC_MEASUREMENT=fr_FR.UTF-8;LC_IDENTIFICATION=fr_FR.UTF-8';
+
+        $this->assertNull(Locale::getFallback($locale));
+    }
 }