Add get_debug_type() function

RFC: https://wiki.php.net/rfc/get_debug_type

Author: Your Name

UPGRADING

@@ -534,6 +534,10 @@ PHP 8.0 UPGRADE NOTES
   . Added fdiv() function, which performs a floating-point division under
     IEEE 754 semantics. Division by zero is considered well-defined and
     will return one of Inf, -Inf or NaN.
+  . Added get_debug_type() function, which returns a type useful for error
+    messages. Unlike get_type(), it uses canonical type names, returns class
+    names for objects, and indicates the resource type for resources.
+    RFC: https://wiki.php.net/rfc/get_debug_type
 
 - Zip:
   . ZipArchive::setMtimeName and ZipArchive::setMtimeIndex to set the

ext/standard/basic_functions.stub.php

@@ -1382,6 +1382,9 @@ function socket_set_timeout($socket, int $seconds, int $microseconds = 0): bool
 /** @param mixed $var */
 function gettype($var): string {}
 
+/** @param mixed $var */
+function get_debug_type($var): string {}
+
 function settype(&$var, string $type): bool {}
 
 /** @param mixed $value */

ext/standard/basic_functions_arginfo.h

@@ -2051,6 +2051,8 @@ ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_gettype, 0, 1, IS_STRING, 0)
 	ZEND_ARG_INFO(0, var)
 ZEND_END_ARG_INFO()
 
+#define arginfo_get_debug_type arginfo_gettype
+
 ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_settype, 0, 2, _IS_BOOL, 0)
 	ZEND_ARG_INFO(1, var)
 	ZEND_ARG_TYPE_INFO(0, type, IS_STRING, 0)
@@ -2792,6 +2794,7 @@ ZEND_FUNCTION(stream_set_chunk_size);
 ZEND_FUNCTION(stream_set_timeout);
 #endif
 ZEND_FUNCTION(gettype);
+ZEND_FUNCTION(get_debug_type);
 ZEND_FUNCTION(settype);
 ZEND_FUNCTION(intval);
 ZEND_FUNCTION(floatval);
@@ -3436,6 +3439,7 @@ static const zend_function_entry ext_functions[] = {
 	ZEND_FALIAS(socket_set_timeout, stream_set_timeout, arginfo_socket_set_timeout)
 #endif
 	ZEND_FE(gettype, arginfo_gettype)
+	ZEND_FE(get_debug_type, arginfo_get_debug_type)
 	ZEND_FE(settype, arginfo_settype)
 	ZEND_FE(intval, arginfo_intval)
 	ZEND_FE(floatval, arginfo_floatval)

ext/standard/tests/general_functions/get_debug_type_basic.phpt

@@ -0,0 +1,57 @@
+--TEST--
+Test get_debug_type() class reading
+--FILE--
+<?php
+
+namespace Demo {
+    class ClassInNamespace {
+
+    }
+}
+
+namespace {
+    class ClassInGlobal { }
+
+    class ToBeExtended {  }
+    interface ToBeImplemented { }
+
+    $fp = fopen(__FILE__, 'r');
+
+    $fp_closed = fopen(__FILE__, 'r');
+    fclose($fp_closed);
+
+    /* tests against an object type */
+    echo get_debug_type(new ClassInGlobal()) . "\n";
+    echo get_debug_type(new Demo\ClassInNamespace()) . "\n";
+    echo get_debug_type(new class {}) . "\n";
+    echo get_debug_type(new class extends ToBeExtended {}) . "\n";
+    echo get_debug_type(new class implements ToBeImplemented {}) . "\n";
+
+    /* scalars */
+    echo get_debug_type("foo") . "\n";
+    echo get_debug_type(false) . "\n";
+    echo get_debug_type(true) . "\n";
+    echo get_debug_type(1) . "\n";
+    echo get_debug_type(1.1) . "\n";
+    echo get_debug_type([]) . "\n";
+    echo get_debug_type(null) . "\n";
+    echo get_debug_type($fp) . "\n";
+    echo get_debug_type($fp_closed) . "\n";
+
+}
+
+--EXPECT--
+ClassInGlobal
+Demo\ClassInNamespace
+class@anonymous
+ToBeExtended@anonymous
+ToBeImplemented@anonymous
+string
+bool
+bool
+int
+float
+array
+null
+resource (stream)
+resource (closed)

ext/standard/type.c

@@ -37,6 +37,52 @@ PHP_FUNCTION(gettype)
 }
 /* }}} */
 
+/* {{{ proto string get_debug_type(mixed var)
+   Returns the type of the variable resolving class names */
+PHP_FUNCTION(get_debug_type)
+{
+	zval *arg;
+	const char *name;
+
+	ZEND_PARSE_PARAMETERS_START(1, 1)
+		Z_PARAM_ZVAL(arg)
+	ZEND_PARSE_PARAMETERS_END();
+
+	switch (Z_TYPE_P(arg)) {
+		case IS_NULL:
+			RETURN_INTERNED_STR(ZSTR_KNOWN(ZEND_STR_NULL_LOWERCASE));
+		case IS_FALSE:
+		case IS_TRUE:
+			RETURN_INTERNED_STR(ZSTR_KNOWN(ZEND_STR_BOOL));
+		case IS_LONG:
+			RETURN_INTERNED_STR(ZSTR_KNOWN(ZEND_STR_INT));
+		case IS_DOUBLE:
+			RETURN_INTERNED_STR(ZSTR_KNOWN(ZEND_STR_FLOAT));
+		case IS_STRING:
+			RETURN_INTERNED_STR(ZSTR_KNOWN(ZEND_STR_STRING));
+		case IS_ARRAY:
+			RETURN_INTERNED_STR(ZSTR_KNOWN(ZEND_STR_ARRAY));
+		case IS_OBJECT:
+			if (Z_OBJ_P(arg)->ce->ce_flags & ZEND_ACC_ANON_CLASS) {
+				name = ZSTR_VAL(Z_OBJ_P(arg)->ce->name);
+				RETURN_NEW_STR(zend_string_init(name, strlen(name), 0));
+			} else {
+				RETURN_STR_COPY(Z_OBJ_P(arg)->ce->name);
+			}
+		case IS_RESOURCE:
+			name = zend_rsrc_list_get_rsrc_type(Z_RES_P(arg));
+			if (name) {
+				RETURN_NEW_STR(zend_strpprintf(0, "resource (%s)", name));
+			} else {
+				RETURN_INTERNED_STR(ZSTR_KNOWN(ZEND_STR_CLOSED_RESOURCE));
+			}
+		default:
+			RETURN_INTERNED_STR(ZSTR_KNOWN(ZEND_STR_UNKNOWN));
+	}
+}
+/* }}} */
+
+
 /* {{{ proto bool settype(mixed &var, string type)
    Set the type of the variable */
 PHP_FUNCTION(settype)