Area code information lost for all MX numbers in last metadata update

Mirrors google/libphonenumber#3535

src/PhoneNumberUtil.php

@@ -169,6 +169,13 @@ class PhoneNumberUtil
         86, // China
     ];
 
+    /**
+     * Set of country codes that doesn't have national prefix, but it has area codes.
+     */
+    protected const COUNTRIES_WITHOUT_NATIONAL_PREFIX_WITH_AREA_CODES = [
+        52, // Mexico
+    ];
+
     /**
      * Set of country calling codes that have geographically assigned mobile numbers. This may not be
      * complete; we add calling codes case by case, as we find geographical mobile numbers or hear
@@ -787,20 +794,25 @@ public function getLengthOfGeographicalAreaCode(PhoneNumber $number): int
         if ($metadata === null) {
             return 0;
         }
+
+        $countryCallingCode = $number->getCountryCode();
+
+
         // If a country doesn't use a national prefix, and this number doesn't have an Italian leading
         // zero, we assume it is a closed dialling plan with no area codes.
-        if (!$metadata->hasNationalPrefix() && !$number->isItalianLeadingZero()) {
+        // Note:this is our general assumption, but there are exceptions which are tracked in
+        // COUNTRIES_WITHOUT_NATIONAL_PREFIX_WITH_AREA_CODES.
+        if (!$metadata->hasNationalPrefix() && !$number->isItalianLeadingZero() && !in_array($countryCallingCode, static::COUNTRIES_WITHOUT_NATIONAL_PREFIX_WITH_AREA_CODES)) {
             return 0;
         }
 
         $type = $this->getNumberType($number);
-        $countryCallingCode = $number->getCountryCode();
 
         if ($type === PhoneNumberType::MOBILE
             // Note this is a rough heuristic; it doesn't cover Indonesia well, for example, where area
             // codes are present for some mobile phones but not for others. We have no better way of
             // representing this in the metadata at this point.
-            && in_array($countryCallingCode, self::GEO_MOBILE_COUNTRIES_WITHOUT_MOBILE_AREA_CODES)
+            && in_array($countryCallingCode, static::GEO_MOBILE_COUNTRIES_WITHOUT_MOBILE_AREA_CODES)
         ) {
             return 0;
         }

tests/core/PhoneNumberUtilTest.php

@@ -330,6 +330,9 @@ public function testGetLengthOfGeographicalAreaCode(): void
         // Italian numbers - there is no national prefix, but it still has an area code.
         $this->assertEquals(2, $this->phoneUtil->getLengthOfGeographicalAreaCode(self::$itNumber));
 
+        // Mexico numbers - there is no national prefix, but it still has an area code.
+        $this->assertEquals(2, $this->phoneUtil->getLengthOfGeographicalAreaCode(self::$mxNumber1));
+
         // Google Singapore. Singapore has no area code and no national prefix.
         $this->assertEquals(0, $this->phoneUtil->getLengthOfGeographicalAreaCode(self::$sgNumber));