Initial checkin

core/template/src/ErrorHandler.php

@@ -0,0 +1,97 @@
+<?php
+
+namespace Smarty;
+
+/**
+ * Smarty error handler to fix new error levels in PHP8 for backwards compatibility
+ * @author     Simon Wisselink
+ */
+class ErrorHandler
+{
+    /**
+     * Allows {$foo->propName} where propName is undefined.
+     * @var bool
+     */
+    public $allowUndefinedProperties = true;
+
+    /**
+     * Allows {$foo.bar} where bar is unset and {$foo.bar1.bar2} where either bar1 or bar2 is unset.
+     * @var bool
+     */
+    public $allowUndefinedArrayKeys = true;
+
+    /**
+     * Allows {$foo->bar} where bar is not an object (e.g. null or false).
+     * @var bool
+     */
+    public $allowDereferencingNonObjects = true;
+
+    private $previousErrorHandler = null;
+
+    /**
+     * Enable error handler to intercept errors
+     */
+    public function activate() {
+        /*
+            Error muting is done because some people implemented custom error_handlers using
+            https://php.net/set_error_handler and for some reason did not understand the following paragraph:
+
+            It is important to remember that the standard PHP error handler is completely bypassed for the
+            error types specified by error_types unless the callback function returns FALSE.
+            error_reporting() settings will have no effect and your error handler will be called regardless -
+            however you are still able to read the current value of error_reporting and act appropriately.
+            Of particular note is that this value will be 0 if the statement that caused the error was
+            prepended by the @ error-control operator.
+        */
+        $this->previousErrorHandler = set_error_handler([$this, 'handleError']);
+    }
+
+    /**
+     * Disable error handler
+     */
+    public function deactivate() {
+        restore_error_handler();
+        $this->previousErrorHandler = null;
+    }
+
+    /**
+     * Error Handler to mute expected messages
+     *
+     * @link https://php.net/set_error_handler
+     *
+     * @param integer $errno Error level
+     * @param         $errstr
+     * @param         $errfile
+     * @param         $errline
+     * @param         $errcontext
+     *
+     * @return bool
+     */
+    public function handleError($errno, $errstr, $errfile, $errline, $errcontext = [])
+    {
+        if ($this->allowUndefinedProperties && preg_match(
+                '/^(Undefined property)/',
+                $errstr
+            )) {
+            return; // suppresses this error
+        }
+
+        if ($this->allowUndefinedArrayKeys && preg_match(
+            '/^(Undefined index|Undefined array key|Trying to access array offset on)/',
+            $errstr
+        )) {
+            return; // suppresses this error
+        }
+
+        if ($this->allowDereferencingNonObjects && preg_match(
+                '/^Attempt to read property ".+?" on/',
+                $errstr
+            )) {
+            return; // suppresses this error
+        }
+
+        // pass all other errors through to the previous error handler or to the default PHP error handler
+        return $this->previousErrorHandler ?
+            call_user_func($this->previousErrorHandler, $errno, $errstr, $errfile, $errline, $errcontext) : false;
+    }
+}