ext/spl: spl_autoload() builds include filename from case-preserved class name

NEWS

@@ -42,6 +42,11 @@ PHP                                                                        NEWS
   . Fixed bug GH-21314 (Different session garbage collector behavior between
     PHP 8.3 and PHP 8.5). (jorgsowa)
 
+- SPL:
+  . spl_autoload() now builds the include file name from the case-preserved
+    class name instead of lowercasing it, fixing autoloading of classes with
+    non-lowercase names on case-sensitive file systems. (jorgsowa)
+
 - Streams:
   . Fixed bug GH-21468 (Segfault in file_get_contents w/ a https URL
     and a proxy set). (CVE-2026-12184) (ndossche)

UPGRADING

@@ -164,6 +164,10 @@ PHP 8.6 UPGRADE NOTES
   . SplFileObject::next() past EOF no longer increments key() without bound.
     SplFileObject::seek() past EOF now produces the same key() value as
     SplTempFileObject; the two previously returned different values.
+  . The default spl_autoload() implementation now builds the include file
+    name from the case-preserved class name instead of its lowercased form.
+    On case-sensitive file systems the file name must match the class name
+    casing (e.g. MyClass.php instead of myclass.php).
 
 - Standard:
   . Form feed (\f) is now added in the default trimmed characters of trim(),

ext/spl/php_spl.c

@@ -249,14 +249,14 @@ PHP_FUNCTION(spl_classes)
 }
 /* }}} */
 
-static bool spl_autoload(zend_string *lc_name, const char *ext, size_t ext_len) /* {{{ */
+static bool spl_autoload(const char *name, size_t name_len, const char *ext, size_t ext_len) /* {{{ */
 {
 	zend_string *class_file;
 	zval dummy;
 	zend_file_handle file_handle;
 	zval result;
 
-	class_file = zend_string_concat2(ZSTR_VAL(lc_name), ZSTR_LEN(lc_name), ext, ext_len);
+	class_file = zend_string_concat2(name, name_len, ext, ext_len);
 
 #if DEFAULT_SLASH != '\\'
 	{
@@ -294,7 +294,7 @@ static bool spl_autoload(zend_string *lc_name, const char *ext, size_t ext_len)
 			efree(new_op_array);
 			zval_ptr_dtor(&result);
 
-			ret = zend_hash_exists(EG(class_table), lc_name);
+			ret = zend_hash_str_find_ptr_lc(EG(class_table), name, name_len) != NULL;
 		}
 	}
 	zend_destroy_file_handle(&file_handle);
@@ -307,7 +307,7 @@ PHP_FUNCTION(spl_autoload)
 {
 	size_t pos_len, pos1_len;
 	char *pos, *pos1;
-	zend_string *class_name, *lc_name, *file_exts = NULL;
+	zend_string *class_name, *file_exts = NULL;
 
 	if (zend_parse_parameters(ZEND_NUM_ARGS(), "S|S!", &class_name, &file_exts) == FAILURE) {
 		RETURN_THROWS();
@@ -325,26 +325,26 @@ PHP_FUNCTION(spl_autoload)
 		pos_len = ZSTR_LEN(file_exts);
 	}
 
-	if (ZSTR_VAL(class_name)[0] == '\\') {
-		lc_name = zend_string_alloc(ZSTR_LEN(class_name) - 1, 0);
-		zend_str_tolower_copy(ZSTR_VAL(lc_name), ZSTR_VAL(class_name) + 1, ZSTR_LEN(class_name) - 1);
-	} else {
-		lc_name = zend_string_tolower(class_name);
+	const char *name = ZSTR_VAL(class_name);
+	size_t name_len = ZSTR_LEN(class_name);
+	if (*name == '\\') {
+		name++;
+		name_len--;
 	}
+
 	while (pos && *pos && !EG(exception)) {
 		pos1 = strchr(pos, ',');
 		if (pos1) {
 			pos1_len = (size_t)(pos1 - pos);
 		} else {
 			pos1_len = pos_len;
 		}
-		if (spl_autoload(lc_name, pos, pos1_len)) {
+		if (spl_autoload(name, name_len, pos, pos1_len)) {
 			break; /* loaded */
 		}
 		pos = pos1 ? pos1 + 1 : NULL;
 		pos_len = pos1? pos_len - pos1_len - 1 : 0;
 	}
-	zend_string_release(lc_name);
 } /* }}} */
 
 /* {{{ Register and return default file extensions for spl_autoload */

ext/spl/tests/autoloading/spl_autoload_001.phpt

@@ -74,15 +74,15 @@ try {
 --EXPECTF--
 ===EMPTY===
 string(9) ".inc,.php"
-%stestclass.inc
+%sTestClass.inc
 Class TestClass could not be loaded
 ===()===
 Class TestClass could not be loaded
 ===(1)===
 Class TestClass could not be loaded
 ===(.inc,,.php.inc)===
-%stestclass
-%stestclass.php.inc
+%sTestClass
+%sTestClass.php.inc
 Class TestClass could not be loaded
 ===()===
 Class TestClass could not be loaded
@@ -97,7 +97,7 @@ bool(false)
 ===LOAD===
 TestFunc1(TestClass)
 TestFunc2(TestClass)
-%stestclass.class.inc
+%sTestClass.class.inc
 bool(true)
 ===NOFUNCTION===
 spl_autoload_register(): Argument #1 ($callback) must be a valid callback or null, function "unavailable_autoload_function" not found or invalid function name

ext/spl/tests/autoloading/spl_autoload_009.phpt

@@ -14,10 +14,10 @@ function my_autoload($name)
 spl_autoload_register("spl_autoload");
 spl_autoload_register("my_autoload");
 
-$obj = new testclass;
+$obj = new TestClass;
 
 ?>
 --EXPECTF--
-%stestclass.inc
-%stestclass.class.inc
+%sTestClass.inc
+%sTestClass.class.inc
 bool(true)

ext/spl/tests/autoloading/spl_autoload_call_basic.phpt

@@ -6,13 +6,13 @@ Jean-Marc Fontaine <jean-marc.fontaine@alterway.fr>
 --FILE--
 <?php
 function customAutolader($class) {
-    require_once __DIR__ . '/testclass.class.inc';
+    require_once __DIR__ . '/TestClass.class.inc';
 }
 spl_autoload_register('customAutolader');
 
 spl_autoload_call('TestClass');
 var_dump(class_exists('TestClass', false));
 ?>
 --EXPECTF--
-%stestclass.class.inc
+%sTestClass.class.inc
 bool(true)

ext/spl/tests/autoloading/spl_autoload_warn_on_false_do_throw.phpt

@@ -3,7 +3,7 @@ spl_autoload_register() function - warn when using false as second argument for
 --FILE--
 <?php
 function customAutolader($class) {
-    require_once __DIR__ . '/testclass.class.inc';
+    require_once __DIR__ . '/TestClass.class.inc';
 }
 spl_autoload_register('customAutolader', false);
 
@@ -12,5 +12,5 @@ var_dump(class_exists('TestClass', false));
 ?>
 --EXPECTF--
 Notice: spl_autoload_register(): Argument #2 ($do_throw) has been ignored, spl_autoload_register() will always throw in %s on line %d
-%stestclass.class.inc
+%sTestClass.class.inc
 bool(true)

ext/spl/tests/dualiterator_001.phpt

@@ -5,7 +5,7 @@ SPL: DualIterator
 
 function spl_examples_autoload($classname)
 {
-    include(__DIR__ . '/' . strtolower($classname) . '.inc');
+    include(__DIR__ . '/' . $classname . '.inc');
 }
 
 spl_autoload_register('spl_examples_autoload');