FileSystem: Add a test for deleting directories with symlinks

tests/ctest/common/CMakeLists.txt

@@ -1,5 +1,6 @@
 add_pcsx2_test(common_test
 	byteswap_tests.cpp
+	filesystem_tests.cpp
 	path_tests.cpp
 	string_util_tests.cpp
 )

tests/ctest/common/filesystem_tests.cpp

@@ -0,0 +1,42 @@
+// SPDX-FileCopyrightText: 2002-2024 PCSX2 Dev Team
+// SPDX-License-Identifier: GPL-3.0+
+
+#include "common/FileSystem.h"
+#include "common/Path.h"
+#include <gtest/gtest.h>
+
+#ifdef __linux__
+
+#include <unistd.h>
+
+TEST(Filesystem, DontFollowSymbolicLinksWhenRecursivelyDeletingDirectories)
+{
+	// Find a suitable location to write some test files.
+	const char* test_dir = "/tmp/pcsx2_filesystem_test";
+	FileSystem::CreateDirectoryPath(test_dir, false);
+
+	// Create a target directory containing a file that shouldn't be deleted.
+	std::string target_dir = Path::Combine(test_dir, "target_dir");
+	FileSystem::CreateDirectoryPath(target_dir.c_str(), false);
+	std::string file_path = Path::Combine(target_dir, "file.txt");
+	ASSERT_TRUE(FileSystem::WriteStringToFile(file_path.c_str(), "Lorem ipsum!"));
+
+	// Create a directory containing a symlink to the target directory.
+	std::string dir_to_delete = Path::Combine(test_dir, "dir_to_delete");
+	FileSystem::CreateDirectoryPath(dir_to_delete.c_str(), false);
+	std::string symlink_path = Path::Combine(dir_to_delete, "link");
+	symlink(target_dir.c_str(), symlink_path.c_str());
+
+	// Delete the directory containing the symlink.
+	ASSERT_TRUE(FileSystem::RecursiveDeleteDirectory(dir_to_delete.c_str()));
+
+	// Make sure the target file didn't get deleted.
+	ASSERT_TRUE(FileSystem::FileExists(file_path.c_str()));
+
+	// Clean up.
+	FileSystem::DeleteFilePath(file_path.c_str());
+	FileSystem::DeleteDirectory(target_dir.c_str());
+	FileSystem::DeleteDirectory(test_dir);
+}
+
+#endif