removed global keyword usage, test under PHP 8.1

- use separate class for internal global variables
- removed `setInstance`
- corrections for multi tag database instances
- start testing under PHP 8.1 on Linux GitHub Action

Author: TheTechsTech

.github/workflows/ezsql-linux.yml

@@ -17,7 +17,7 @@ jobs:
       fail-fast: false
       matrix:
         operating-system: [ubuntu-18.04]
-        php-versions: ['7.4', '8.0']
+        php-versions: ['7.4', '8.0', '8.1']
 
     steps:
       - name: Checkout

composer.json

@@ -39,7 +39,7 @@
         "issues": "https://github.com/ezSQL/ezSQL/issues"
     },
     "require": {
-        "php": "^7.1 || ^8",
+        "php": ">7.1",
         "psr/container": "^1.0"
     },
     "provide": {
@@ -55,7 +55,7 @@
         }
     },
     "require-dev": {
-        "phpunit/phpunit": "^6 || ^7 || ^8"
+        "phpunit/phpunit": "^6 | ^7 | ^8"
     },
     "autoload-dev": {
         "psr-4": {

lib/Database.php

@@ -4,8 +4,8 @@
 
 namespace ezsql;
 
+use ezsql\Db;
 use ezsql\DInjector;
-use function ezsql\functions\setInstance;
 
 class Database
 {
@@ -15,7 +15,10 @@ class Database
      * @var float
      */
     private static $_ts = null;
-    private static $factory = null;
+
+    /**
+     * @var ezQueryInterface[]
+     */
     private static $instances = [];
 
     // @codeCoverageIgnoreStart
@@ -67,10 +70,10 @@ public function __wakeup()
      * @param string $tag Store the instance for later use
      * @return Database\ez_pdo|Database\ez_pgsql|Database\ez_sqlsrv|Database\ez_sqlite3|Database\ez_mysqli
      */
-    public static function initialize(?string $vendor = null, ?array $setting = null, ?string $tag = null)
+    public static function initialize(?string $vendor = null, ?array $setting = null, ?string $tag = null): ezQueryInterface
     {
         if (isset(self::$instances[$vendor]) && empty($setting) && empty($tag))
-            return setInstance(self::$instances[$vendor]) ? self::$instances[$vendor] : false;
+            return self::$instances[$vendor];
 
         if (empty($vendor) || empty($setting)) {
             throw new \Exception(\MISSING_CONFIGURATION);
@@ -79,7 +82,7 @@ public static function initialize(?string $vendor = null, ?array $setting = null
             $key = $vendor;
             $value = \VENDOR[$key];
 
-            if (empty($GLOBALS['ez' . $key]) || !empty($tag)) {
+            if (!Db::has('ez' . $key) || !empty($tag)) {
                 $di = new DInjector();
                 $di->set($key, $value);
                 $di->set('ezsql\ConfigInterface', 'ezsql\Config');
@@ -90,8 +93,9 @@ public static function initialize(?string $vendor = null, ?array $setting = null
                 }
             }
 
-            setInstance($GLOBALS['ez' . $key]);
-            return $GLOBALS['ez' . $key];
+            $db = Db::get('ez' . $key);
+            Db::set('global', $db);
+            return $db;
         }
     }
 

lib/Database/ez_mysqli.php

@@ -5,10 +5,10 @@
 namespace ezsql\Database;
 
 use Exception;
+use ezsql\Db;
 use ezsql\ezsqlModel;
 use ezsql\ConfigInterface;
 use ezsql\DatabaseInterface;
-use function ezsql\functions\setInstance;
 
 class ez_mysqli extends ezsqlModel implements DatabaseInterface
 {
@@ -44,9 +44,9 @@ public function __construct(ConfigInterface $settings = null)
         parent::__construct();
         $this->database = $settings;
 
-        if (empty($GLOBALS['ez' . \MYSQLI]))
-            $GLOBALS['ez' . \MYSQLI] = $this;
-        setInstance($this);
+        if (!Db::has('ez' . \MYSQLI))
+            Db::set('ez' . \MYSQLI, $this);
+        Db::set('global', $this);
     } // __construct
 
     public function settings()

lib/Database/ez_pdo.php

@@ -5,10 +5,10 @@
 namespace ezsql\Database;
 
 use Exception;
+use ezsql\Db;
 use ezsql\ezsqlModel;
 use ezsql\ConfigInterface;
 use ezsql\DatabaseInterface;
-use function ezsql\functions\setInstance;
 
 class ez_pdo extends ezsqlModel implements DatabaseInterface
 {
@@ -47,9 +47,9 @@ public function __construct(ConfigInterface $settings = null)
         // Turn on track errors
         ini_set('track_errors', '1');
 
-        if (empty($GLOBALS['ez' . \Pdo]))
-            $GLOBALS['ez' . \Pdo] = $this;
-        setInstance($this);
+        if (!Db::has('ez' . \Pdo))
+            Db::set('ez' . \Pdo, $this);
+        Db::set('global', $this);
     } // __construct
 
     public function settings()

lib/Database/ez_pgsql.php

@@ -5,10 +5,10 @@
 namespace ezsql\Database;
 
 use Exception;
+use ezsql\Db;
 use ezsql\ezsqlModel;
 use ezsql\ConfigInterface;
 use ezsql\DatabaseInterface;
-use function ezsql\functions\setInstance;
 
 class ez_pgsql extends ezsqlModel implements DatabaseInterface
 {
@@ -44,9 +44,9 @@ public function __construct(ConfigInterface $settings = null)
         parent::__construct();
         $this->database = $settings;
 
-        if (empty($GLOBALS['ez' . \PGSQL]))
-            $GLOBALS['ez' . \PGSQL] = $this;
-        setInstance($this);
+        if (!Db::has('ez' . \PGSQL))
+            Db::set('ez' . \PGSQL, $this);
+        Db::set('global', $this);
     } // __construct
 
     public function settings()

lib/Database/ez_sqlite3.php

@@ -5,10 +5,10 @@
 namespace ezsql\Database;
 
 use Exception;
+use ezsql\Db;
 use ezsql\ezsqlModel;
 use ezsql\ConfigInterface;
 use ezsql\DatabaseInterface;
-use function ezsql\functions\setInstance;
 
 class ez_sqlite3 extends ezsqlModel implements DatabaseInterface
 {
@@ -51,9 +51,9 @@ public function __construct(ConfigInterface $settings = null)
         // Turn on track errors
         ini_set('track_errors', '1');
 
-        if (!isset($GLOBALS['ez' . \SQLITE3]))
-            $GLOBALS['ez' . \SQLITE3] = $this;
-        setInstance($this);
+        if (!Db::has('ez' . \SQLITE3))
+            Db::set('ez' . \SQLITE3, $this);
+        Db::set('global', $this);
     }
 
     public function settings()

lib/Database/ez_sqlsrv.php

@@ -5,10 +5,10 @@
 namespace ezsql\Database;
 
 use Exception;
+use ezsql\Db;
 use ezsql\ezsqlModel;
 use ezsql\ConfigInterface;
 use ezsql\DatabaseInterface;
-use function ezsql\functions\setInstance;
 
 class ez_sqlsrv extends ezsqlModel implements DatabaseInterface
 {
@@ -53,9 +53,9 @@ public function __construct(ConfigInterface $settings = null)
         parent::__construct();
         $this->database = $settings;
 
-        if (empty($GLOBALS['ez' . \SQLSRV]))
-            $GLOBALS['ez' . \SQLSRV] = $this;
-        setInstance($this);
+        if (!Db::has('ez' . \SQLSRV))
+            Db::set('ez' . \SQLSRV, $this);
+        Db::set('global', $this);
     }
 
     public function settings()

lib/Db.php

@@ -0,0 +1,66 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ezsql;
+
+use ezsql\ezQueryInterface;
+
+/**
+ * Used internally for needed **global** variables.
+ *
+ * @internal
+ */
+final class Db
+{
+    /**
+     * @var ezQueryInterface[]
+     */
+    protected static $storage;
+
+    /**
+     * @param string $key
+     * @param mixed $value
+     * @return void
+     */
+    public static function set(string $key, $value): void
+    {
+        self::$storage[$key] = $value;
+    }
+
+    /**
+     * @param string $key
+     * @return ezQueryInterface
+     */
+    public static function get(string $key): ?ezQueryInterface
+    {
+        return self::$storage[$key] ?? null;
+    }
+
+    /**
+     * @param string $tag
+     * @return boolean
+     */
+    public static function has(string $tag): bool
+    {
+        return isset(self::$storage[$tag]);
+    }
+
+    /**
+     * @param string $tag
+     * @return void
+     */
+    public static function clear(string $tag): void
+    {
+        if (self::has($tag))
+            unset(self::$storage[$tag]);
+    }
+
+    /**
+     * @return void
+     */
+    public static function reset(): void
+    {
+        self::$storage = null;
+    }
+}

lib/ezFunctions.php

@@ -9,9 +9,28 @@
 use ezsql\Database;
 use ezsql\ezQueryInterface;
 use ezsql\DatabaseInterface;
+use ezsql\Db;
 use ezsql\ezsqlModelInterface;
 
 if (!\function_exists('ezFunctions')) {
+    /**
+     * Returns the global database class, last created instance.
+     *
+     * @return ezQueryInterface|null
+     */
+    function getInstance(): ?ezQueryInterface
+    {
+        return Db::get('global');
+    }
+
+    /**
+     * Clear/unset the global database class instance.
+     */
+    function clearInstance(): void
+    {
+        Db::clear('global');
+    }
+
     /**
      * Initialize and connect a vendor's database.
      *
@@ -138,7 +157,7 @@ function sqliteInstance(array $databaseSetting = null, string $instanceTag = nul
      *
      * @return string|null `mysqli`|`pgsql`|`sqlite3`|`sqlsrv`
      */
-    function get_vendor(DatabaseInterface $instance = null)
+    function get_vendor(DatabaseInterface $instance = null): ?string
     {
         return ezSchema::vendor($instance);
     }
@@ -148,7 +167,7 @@ function get_vendor(DatabaseInterface $instance = null)
      *
      * @return string
      */
-    function to_string($arrays, $separation = ',')
+    function to_string($arrays, $separation = ','): string
     {
         return ezQuery::to_string($arrays, $separation);
     }
@@ -479,38 +498,6 @@ function notBetween($x, $y, $y2, ...$args)
         return $expression;
     }
 
-    /**
-     * Sets the global class instance for functions to call class methods directly.
-     *
-     * @param ezQueryInterface|null $ezSQL
-     *
-     * @return boolean - `true`, or `false` for error
-     */
-    function setInstance(ezQueryInterface $ezSQL = null)
-    {
-        global $ezInstance;
-        $status = false;
-
-        if ($ezSQL instanceof ezQueryInterface) {
-            $ezInstance = $ezSQL;
-            $status = true;
-        }
-
-        return $status;
-    }
-
-    /**
-     * Returns the global database class, last created instance or the one set with `setInstance()`.
-     *
-     * @return ezQueryInterface|null
-     */
-    function getInstance()
-    {
-        global $ezInstance;
-
-        return ($ezInstance instanceof ezQueryInterface) ? $ezInstance : null;
-    }
-
     /**
      * Get multiple row result set from the database (previously cached results).
      * Returns a multi dimensional array.
@@ -547,17 +534,6 @@ function get_results($output = \OBJECT, $instance = null)
             : false;
     }
 
-    /**
-     * Clear/unset the global database class instance.
-     */
-    function clearInstance()
-    {
-        global $ezInstance;
-        $GLOBALS['ezInstance'] = null;
-        $ezInstance = null;
-        unset($GLOBALS['ezInstance']);
-    }
-
     /**
      * Clean input string of XSS, html, javascript, etc...
      * @param string $string