Define polyfilled T_* constants from Tokenizer as int

phpunit.xml.dist

@@ -31,6 +31,9 @@
             <directory>./src/Standards/Squiz/Tests/</directory>
             <directory>./src/Standards/Zend/Tests/</directory>
         </testsuite>
+        <testsuite name="End2EndPhpt">
+            <directory suffix=".phpt">tests/EndToEndPhpt/</directory>
+        </testsuite>
     </testsuites>
 
     <groups>

src/Util/Tokens.php

@@ -10,6 +10,7 @@
 
 namespace PHP_CodeSniffer\Util;
 
+// PHPCS native tokens.
 define('T_NONE', 'PHPCS_T_NONE');
 define('T_OPEN_CURLY_BRACKET', 'PHPCS_T_OPEN_CURLY_BRACKET');
 define('T_CLOSE_CURLY_BRACKET', 'PHPCS_T_CLOSE_CURLY_BRACKET');
@@ -70,84 +71,6 @@
 define('T_TYPE_OPEN_PARENTHESIS', 'PHPCS_T_TYPE_OPEN_PARENTHESIS');
 define('T_TYPE_CLOSE_PARENTHESIS', 'PHPCS_T_TYPE_CLOSE_PARENTHESIS');
 
-/*
- * {@internal IMPORTANT: all PHP native polyfilled tokens MUST be added to the
- * `PHP_CodeSniffer\Tests\Core\Util\Tokens\TokenNameTest::dataPolyfilledPHPNativeTokens()` test method!}
- */
-
-// Some PHP 7.4 tokens, replicated for lower versions.
-if (defined('T_COALESCE_EQUAL') === false) {
-    define('T_COALESCE_EQUAL', 'PHPCS_T_COALESCE_EQUAL');
-}
-
-if (defined('T_BAD_CHARACTER') === false) {
-    define('T_BAD_CHARACTER', 'PHPCS_T_BAD_CHARACTER');
-}
-
-if (defined('T_FN') === false) {
-    define('T_FN', 'PHPCS_T_FN');
-}
-
-// Some PHP 8.0 tokens, replicated for lower versions.
-if (defined('T_NULLSAFE_OBJECT_OPERATOR') === false) {
-    define('T_NULLSAFE_OBJECT_OPERATOR', 'PHPCS_T_NULLSAFE_OBJECT_OPERATOR');
-}
-
-if (defined('T_NAME_QUALIFIED') === false) {
-    define('T_NAME_QUALIFIED', 'PHPCS_T_NAME_QUALIFIED');
-}
-
-if (defined('T_NAME_FULLY_QUALIFIED') === false) {
-    define('T_NAME_FULLY_QUALIFIED', 'PHPCS_T_NAME_FULLY_QUALIFIED');
-}
-
-if (defined('T_NAME_RELATIVE') === false) {
-    define('T_NAME_RELATIVE', 'PHPCS_T_NAME_RELATIVE');
-}
-
-if (defined('T_MATCH') === false) {
-    define('T_MATCH', 'PHPCS_T_MATCH');
-}
-
-if (defined('T_ATTRIBUTE') === false) {
-    define('T_ATTRIBUTE', 'PHPCS_T_ATTRIBUTE');
-}
-
-// Some PHP 8.1 tokens, replicated for lower versions.
-if (defined('T_AMPERSAND_FOLLOWED_BY_VAR_OR_VARARG') === false) {
-    define('T_AMPERSAND_FOLLOWED_BY_VAR_OR_VARARG', 'PHPCS_T_AMPERSAND_FOLLOWED_BY_VAR_OR_VARARG');
-}
-
-if (defined('T_AMPERSAND_NOT_FOLLOWED_BY_VAR_OR_VARARG') === false) {
-    define('T_AMPERSAND_NOT_FOLLOWED_BY_VAR_OR_VARARG', 'PHPCS_T_AMPERSAND_NOT_FOLLOWED_BY_VAR_OR_VARARG');
-}
-
-if (defined('T_READONLY') === false) {
-    define('T_READONLY', 'PHPCS_T_READONLY');
-}
-
-if (defined('T_ENUM') === false) {
-    define('T_ENUM', 'PHPCS_T_ENUM');
-}
-
-// Some PHP 8.4 tokens, replicated for lower versions.
-if (defined('T_PUBLIC_SET') === false) {
-    define('T_PUBLIC_SET', 'PHPCS_T_PUBLIC_SET');
-}
-
-if (defined('T_PROTECTED_SET') === false) {
-    define('T_PROTECTED_SET', 'PHPCS_T_PROTECTED_SET');
-}
-
-if (defined('T_PRIVATE_SET') === false) {
-    define('T_PRIVATE_SET', 'PHPCS_T_PRIVATE_SET');
-}
-
-// Some PHP 8.5 tokens, replicated for lower versions.
-if (defined('T_VOID_CAST') === false) {
-    define('T_VOID_CAST', 'PHPCS_T_VOID_CAST');
-}
-
 // Tokens used for parsing doc blocks.
 define('T_DOC_COMMENT_STAR', 'PHPCS_T_DOC_COMMENT_STAR');
 define('T_DOC_COMMENT_WHITESPACE', 'PHPCS_T_DOC_COMMENT_WHITESPACE');
@@ -163,6 +86,8 @@
 define('T_PHPCS_IGNORE', 'PHPCS_T_PHPCS_IGNORE');
 define('T_PHPCS_IGNORE_FILE', 'PHPCS_T_PHPCS_IGNORE_FILE');
 
+Tokens::polyfillTokenizerConstants();
+
 final class Tokens
 {
 
@@ -612,6 +537,13 @@ final class Tokens
         T_YIELD_FROM   => T_YIELD_FROM,
     ];
 
+    /**
+     * Mapping table for polyfilled constants
+     *
+     * @var array<int, string>
+     */
+    private static $polyfillMappingTable = [];
+
     /**
      * The token weightings.
      *
@@ -943,12 +875,12 @@ final class Tokens
      */
     public static function tokenName($token)
     {
-        if (is_string($token) === false) {
-            // PHP-supplied token name.
-            return token_name($token);
+        if (is_string($token) === true) {
+            // PHPCS native token.
+            return substr($token, 6);
         }
 
-        return substr($token, 6);
+        return (self::$polyfillMappingTable[$token] ?? token_name($token));
     }
 
 
@@ -991,4 +923,98 @@ public static function getHighestWeightedToken(array $tokens)
 
         return $highestType;
     }
+
+
+    /**
+     * Polyfill tokenizer (T_*) constants.
+     *
+     * {@internal IMPORTANT: all PHP native polyfilled tokens MUST be added to the
+     * `PHP_CodeSniffer\Tests\Core\Util\Tokens\TokenNameTest::dataPolyfilledPHPNativeTokens()` test method!}
+     *
+     * @return void
+     */
+    public static function polyfillTokenizerConstants(): void
+    {
+        // Ideally this would be a private class constant. We cannot do that
+        // here as the constants that we are polyfilling in this method are
+        // used in some of the class constants for this class. If we reference
+        // any class constants or properties before this method has fully run,
+        // PHP will intitialise the class, leading to warnings about undefined
+        // T_* constants.
+        $tokensToPolyfill = [
+            // PHP 7.4 native tokens.
+            'T_BAD_CHARACTER',
+            'T_COALESCE_EQUAL',
+            'T_FN',
+
+            // PHP 8.0 native tokens.
+            'T_ATTRIBUTE',
+            'T_MATCH',
+            'T_NAME_FULLY_QUALIFIED',
+            'T_NAME_QUALIFIED',
+            'T_NAME_RELATIVE',
+            'T_NULLSAFE_OBJECT_OPERATOR',
+
+            // PHP 8.1 native tokens.
+            'T_AMPERSAND_FOLLOWED_BY_VAR_OR_VARARG',
+            'T_AMPERSAND_NOT_FOLLOWED_BY_VAR_OR_VARARG',
+            'T_ENUM',
+            'T_READONLY',
+
+            // PHP 8.4 native tokens.
+            'T_PRIVATE_SET',
+            'T_PROTECTED_SET',
+            'T_PUBLIC_SET',
+
+            // PHP 8.5 native tokens.
+            'T_VOID_CAST',
+        ];
+
+        // <https://www.php.net/manual/en/tokens.php>
+        // The PHP manual suggests "using big numbers like 10000" for
+        // polyfilled T_* constants. We have arbitrarily chosen to start our
+        // numbering scheme from 135_000.
+        $nextTokenNumber = 135000;
+
+        // This variable is necessary to avoid collisions with any other
+        // libraries which also polyfill T_* constants.
+        // array_flip()/isset() because in_array() is slow.
+        $existingConstants = array_flip(get_defined_constants(true)['tokenizer']);
+        foreach ((get_defined_constants(true)['user'] ?? []) as $k => $v) {
+            if (isset($k[2]) === false || $k[0] !== 'T' || $k[1] !== '_') {
+                // We only care about T_* constants.
+                continue;
+            }
+
+            if (isset($existingConstants[$v]) === true) {
+                throw new \Exception("Externally polyfilled tokenizer constant value collision detected! $k has the same value as {$existingConstants[$v]}");
+            }
+
+            $existingConstants[$v] = $k;
+        }
+
+        $polyfillMappingTable = [];
+
+        foreach ($tokensToPolyfill as $tokenName) {
+            if (isset(get_defined_constants(true)['tokenizer'][$tokenName]) === true) {
+                // This is a PHP native token, which is already defined by PHP.
+                continue;
+            }
+
+            if (defined($tokenName) === false) {
+                while (isset($existingConstants[$nextTokenNumber]) === true) {
+                    $nextTokenNumber++;
+                }
+
+                define($tokenName, $nextTokenNumber);
+                $existingConstants[$nextTokenNumber] = $tokenName;
+            }
+
+            $polyfillMappingTable[constant($tokenName)] = $tokenName;
+        }
+
+        // Be careful to not reference this class anywhere in this method until
+        // *after* all constants have been polyfilled.
+        self::$polyfillMappingTable = $polyfillMappingTable;
+    }
 }

tests/Core/Util/Tokens/TokenNameTest.php

@@ -16,6 +16,7 @@
  * Tests for the \PHP_CodeSniffer\Util\Tokens::tokenName() method.
  *
  * @covers \PHP_CodeSniffer\Util\Tokens::tokenName
+ * @covers \PHP_CodeSniffer\Util\Tokens::polyfillTokenizerConstants
  */
 final class TokenNameTest extends TestCase
 {

tests/EndToEndPhpt/Util/Tokens/polyfillTokenizerConstants-collision-php.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Detect when the value of a polyfilled PHP token collides with a value already used by an existing internal PHP token.
+--SKIPIF--
+<?php
+if (version_compare(PHP_VERSION, "8.4", ">=")) {
+    echo "skip because tokens used in this test already exist in PHP 8.4 so we cannot test polyfilling them", PHP_EOL;
+}
+--FILE--
+<?php
+define('T_PUBLIC_SET', T_STRING);
+require('src/Util/Tokens.php');
+--EXPECTF--
+Fatal error: Uncaught Exception: Externally polyfilled tokenizer constant value collision detected! T_PUBLIC_SET has the same value as T_STRING in %s:%d
+Stack trace:
+#0 %s(%d): PHP_CodeSniffer\Util\Tokens::polyfillTokenizerConstants()
+#1 Standard input code(%d): require('...')
+#2 {main}
+  thrown in %s on line %d

tests/EndToEndPhpt/Util/Tokens/polyfillTokenizerConstants-collision-user.phpt

@@ -0,0 +1,20 @@
+--TEST--
+Detect when two or more polyfilled PHP tokens have the same value.
+--SKIPIF--
+<?php
+if (version_compare(PHP_VERSION, "8.4", ">=")) {
+    echo "skip because tokens used in this test already exist in PHP 8.4 so we cannot test polyfilling them", PHP_EOL;
+}
+--FILE--
+<?php
+define('T_PRIVATE_SET', 10000);
+define('T_PROTECTED_SET', 10000);
+define('T_PUBLIC_SET', 10000);
+require('src/Util/Tokens.php');
+--EXPECTF--
+Fatal error: Uncaught Exception: Externally polyfilled tokenizer constant value collision detected! T_PROTECTED_SET has the same value as T_PRIVATE_SET in %s:%d
+Stack trace:
+#0 %s(%d): PHP_CodeSniffer\Util\Tokens::polyfillTokenizerConstants()
+#1 Standard input code(%d): require('...')
+#2 {main}
+  thrown in %s on line %d

tests/EndToEndPhpt/Util/Tokens/polyfillTokenizerConstants-number.phpt

@@ -0,0 +1,14 @@
+--TEST--
+Detect when an external party defines a PHP token polyfill with a number that we would have used.
+--SKIPIF--
+<?php
+if (version_compare(PHP_VERSION, "8.4", ">=")) {
+    echo "skip because tokens used in this test already exist in PHP 8.4 so we cannot test polyfilling them", PHP_EOL;
+}
+--FILE--
+<?php
+define('T_PUBLIC_SET', 135000);
+require('src/Util/Tokens.php');
+echo T_PRIVATE_SET, PHP_EOL; // ..0 is used, so this becomes ..1
+--EXPECT--
+135001

tests/EndToEndPhpt/Util/Tokens/polyfillTokenizerConstants-skip-names.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Value collision with a non-tokenizer constant should not cause an error.
+--SKIPIF--
+<?php
+if (version_compare(PHP_VERSION, "8.4", ">=")) {
+    echo "skip because tokens used in this test already exist in PHP 8.4 so we cannot test polyfilling them", PHP_EOL;
+}
+--FILE--
+<?php
+// Using T_STRING as a value because that would be a collision (and throw) if the constant name looked like a tokenizer constant.
+define('T_', T_STRING); // Too short
+define('ONE', T_STRING); // First character is not 'T'
+define('TWO', T_STRING); // Second character is not '_'
+require('src/Util/Tokens.php');
+echo 'No conflicts', PHP_EOL;
+--EXPECT--
+No conflicts