Fix GH-12721: SplFileInfo::getFilename() segfault in combination with GlobIterator and no directory separator

This broke in 7cd8879 and 9bae9ab. NULL is a perfectly valid return
value that should be handled.

Closes GH-12722.

NEWS

@@ -22,6 +22,10 @@ PHP                                                                        NEWS
 - PHPDBG:
   . Fixed bug GH-12675 (MEMORY_LEAK in phpdbg_prompt.c). (nielsdos)
 
+- SPL:
+  . Fixed bug GH-12721 (SplFileInfo::getFilename() segfault in combination
+    with GlobIterator and no directory separator). (nielsdos)
+
 - SQLite3:
   . Fixed bug GH-12633 (sqlite3_defensive.phpt fails with sqlite 3.44.0).
     (SakiTakamachi)

ext/spl/spl_directory.c

@@ -925,7 +925,6 @@ PHP_METHOD(SplFileInfo, getFilename)
 
 	path = spl_filesystem_object_get_path(intern);
 
-	ZEND_ASSERT(path);
 	if (path && ZSTR_LEN(path) && ZSTR_LEN(path) < ZSTR_LEN(intern->file_name)) {
 		/* +1 to skip the trailing / of the path in the file name */
 		size_t path_len = ZSTR_LEN(path) + 1;
@@ -933,7 +932,9 @@ PHP_METHOD(SplFileInfo, getFilename)
 	} else {
 		RETVAL_STR_COPY(intern->file_name);
 	}
-	zend_string_release_ex(path, /* persistent */ false);
+	if (path) {
+		zend_string_release_ex(path, /* persistent */ false);
+	}
 }
 /* }}} */
 
@@ -973,14 +974,16 @@ PHP_METHOD(SplFileInfo, getExtension)
 
 	path = spl_filesystem_object_get_path(intern);
 
-	if (ZSTR_LEN(path) && ZSTR_LEN(path) < ZSTR_LEN(intern->file_name)) {
+	if (path && ZSTR_LEN(path) && ZSTR_LEN(path) < ZSTR_LEN(intern->file_name)) {
 		fname = ZSTR_VAL(intern->file_name) + ZSTR_LEN(path) + 1;
 		flen = ZSTR_LEN(intern->file_name) - (ZSTR_LEN(path) + 1);
 	} else {
 		fname = ZSTR_VAL(intern->file_name);
 		flen = ZSTR_LEN(intern->file_name);
 	}
-	zend_string_release_ex(path, /* persistent */ false);
+	if (path) {
+		zend_string_release_ex(path, /* persistent */ false);
+	}
 
 	ret = php_basename(fname, flen, NULL, 0);
 
@@ -1052,7 +1055,9 @@ PHP_METHOD(SplFileInfo, getBasename)
 		fname = ZSTR_VAL(intern->file_name);
 		flen = ZSTR_LEN(intern->file_name);
 	}
-	zend_string_release_ex(path, /* persistent */ false);
+	if (path) {
+		zend_string_release_ex(path, /* persistent */ false);
+	}
 
 	RETURN_STR(php_basename(fname, flen, suffix, slen));
 }

ext/spl/tests/gh12721.phpt

@@ -0,0 +1,51 @@
+--TEST--
+GH-12721 (SplFileInfo::getFilename() segfault in combination with GlobIterator and no directory separator)
+--FILE--
+<?php
+
+file_put_contents('file1.gh12721', 'hello');
+
+echo "--- No slash ---\n";
+
+foreach (new GlobIterator('*.gh12721') as $fileInfo) {
+	echo $fileInfo->getFilename(), "\n";
+	echo $fileInfo->getExtension(), "\n";
+	echo $fileInfo->getBasename(), "\n";
+	var_dump($fileInfo->getFileInfo());
+}
+
+echo "--- With slash ---\n";
+
+foreach (new GlobIterator('./*.gh12721') as $fileInfo) {
+	echo $fileInfo->getFilename(), "\n";
+	echo $fileInfo->getExtension(), "\n";
+	echo $fileInfo->getBasename(), "\n";
+	var_dump($fileInfo->getFileInfo());
+}
+
+?>
+--CLEAN--
+<?php
+@unlink('file1.gh12721');
+?>
+--EXPECTF--
+--- No slash ---
+file1.gh12721
+gh12721
+file1.gh12721
+object(SplFileInfo)#4 (2) {
+  ["pathName":"SplFileInfo":private]=>
+  string(13) "file1.gh12721"
+  ["fileName":"SplFileInfo":private]=>
+  string(13) "file1.gh12721"
+}
+--- With slash ---
+file1.gh12721
+gh12721
+file1.gh12721
+object(SplFileInfo)#3 (2) {
+  ["pathName":"SplFileInfo":private]=>
+  string(15) "%sfile1.gh12721"
+  ["fileName":"SplFileInfo":private]=>
+  string(13) "file1.gh12721"
+}