Add type hints to extract() methods

Add ?string parameter and array return type hints to all extract()
methods. This fixes PHP 8.1+ deprecation warnings about passing null
to string functions.

Author: jbilbo

CHANGELOG.md

@@ -6,6 +6,7 @@ project adheres to [Semantic Versioning](http://semver.org/).
 ### Changed
 - Minimum PHP version is now 7.2 (previously 5.4)
 - Migrate CI from Travis to GitHub Actions
+- Add type hints to all `extract()` methods (`?string` parameter, `array` return)
 
 ### Security
 - Upgrade PHPUnit to 8.5.52 to fix unsafe deserialization vulnerability

phpunit.xml

@@ -1,6 +1,6 @@
 <phpunit colors="true" bootstrap="vendor/autoload.php">
   <testsuites>
-    <testsuite>
+    <testsuite name="Identifiers">
       <directory>tests</directory>
     </testsuite>
   </testsuites>

src/AdsBibcode.php

@@ -3,8 +3,9 @@
 
 class AdsBibcode
 {
-    public static function extract($str)
+    public static function extract(?string $str): array
     {
+        $str = $str ?? '';
         preg_match_all('/\b\d{4}[a-z][0-9a-z&.]{14}\b/ui', $str, $matches);
 
         return $matches[0];

src/ArxivId.php

@@ -29,8 +29,10 @@ class ArxivId
 }xiu
 EOT;
 
-    public static function extract($str)
+    public static function extract(?string $str): array
     {
+        $str = $str ?? '';
+
         return array_merge(self::extractPre2007ArxivIds($str), self::extractPost2007ArxivIds($str));
     }
 

src/Doi.php

@@ -32,8 +32,9 @@ class Doi
 }xu
 EOT;
 
-    public static function extract($str)
+    public static function extract(?string $str): array
     {
+        $str = $str ?? '';
         preg_match_all(self::REGEXP, mb_strtolower($str, 'UTF-8'), $matches);
 
         return $matches[0];

src/Handle.php

@@ -3,8 +3,9 @@
 
 class Handle
 {
-    public static function extract($str)
+    public static function extract(?string $str): array
     {
+        $str = $str ?? '';
         preg_match_all('#\b[\d.]+/\S+\b#u', $str, $matches);
 
         return $matches[0];

src/Isbn.php

@@ -48,8 +48,10 @@ class Isbn
 }xu
 EOT;
 
-    public static function extract($str)
+    public static function extract(?string $str): array
     {
+        $str = $str ?? '';
+
         return array_merge(self::extractIsbnAs($str), self::extractIsbn13s($str), self::extractIsbn10s($str));
     }
 
@@ -123,9 +125,9 @@ private static function stripHyphenation($match, $limit)
         return $isbn;
     }
 
-    private static function isValidIsbn13($str)
+    private static function isValidIsbn13(?string $str): bool
     {
-        if (strlen($str) !== 13) {
+        if ($str === null || strlen($str) !== 13) {
             return false;
         }
 
@@ -134,9 +136,9 @@ private static function isValidIsbn13($str)
         return $checkDigit === (int) $str[12];
     }
 
-    private static function isValidIsbn10($str)
+    private static function isValidIsbn10(?string $str): bool
     {
-        if (strlen($str) !== 10) {
+        if ($str === null || strlen($str) !== 10) {
             return false;
         }
 

src/NationalClinicalTrialId.php

@@ -3,8 +3,9 @@
 
 class NationalClinicalTrialId
 {
-    public static function extract($str)
+    public static function extract(?string $str): array
     {
+        $str = $str ?? '';
         preg_match_all('/\bNCT\d+\b/ui', $str, $matches);
 
         return array_map('strtoupper', $matches[0]);

src/OrcidId.php

@@ -4,8 +4,9 @@
 
 class OrcidId
 {
-    public static function extract($str)
+    public static function extract(?string $str): array
     {
+        $str = $str ?? '';
         preg_match_all('/\d{4}-\d{4}-\d{4}-\d{3}[\dX]/i', $str, $matches);
 
         return array_filter(array_map('strtoupper', $matches[0]), [__CLASS__, 'isValid']);

src/PubmedId.php

@@ -38,8 +38,10 @@ class PubmedId
 }xu
 EOT;
 
-    public static function extract($str)
+    public static function extract(?string $str): array
     {
+        $str = $str ?? '';
+
         return array_merge(self::extractPubmedIds($str), self::extractPubmedUris($str));
     }