From 5e038259812dfa3a3b5bf86379780f019126fda3 Mon Sep 17 00:00:00 2001 From: Josh Soref Date: Thu, 25 Dec 2025 09:05:42 -0500 Subject: [PATCH] amend! mingw: support long paths mingw: support long paths Windows paths are typically limited to MAX_PATH = 260 characters, even though the underlying NTFS file system supports paths up to 32,767 chars. This limitation is also evident in Windows Explorer, cmd.exe and many other applications (including IDEs). Particularly annoying is that most Windows APIs return bogus error codes if a relative path only barely exceeds MAX_PATH in conjunction with the current directory, e.g. ERROR_PATH_NOT_FOUND / ENOENT instead of the infinitely more helpful ERROR_FILENAME_EXCED_RANGE / ENAMETOOLONG. Many Windows wide char APIs support longer than MAX_PATH paths through the file namespace prefix ('\\?\' or '\\?\UNC\') followed by an absolute path. Notable exceptions include functions dealing with executables and the current directory (CreateProcess, LoadLibrary, Get/SetCurrentDirectory) as well as the entire shell API (ShellExecute, SHGetSpecialFolderPath...). Introduce a handle_long_path function to check the length of a specified path properly (and fail with ENAMETOOLONG), and to optionally expand long paths using the '\\?\' file namespace prefix. Short paths will not be modified, so we don't need to worry about device names (NUL, CON, AUX). Contrary to MSDN docs, the GetFullPathNameW function doesn't seem to be limited to MAX_PATH (at least not on Win7), so we can use it to do the heavy lifting of the conversion (translate '/' to '\', eliminate '.' and '..', and make an absolute path). Add long path error checking to xutftowcs_path for APIs with hard MAX_PATH limit. Add a new MAX_LONG_PATH constant and xutftowcs_long_path function for APIs that support long paths. While improved error checking is always active, long paths support must be explicitly enabled via 'core.longpaths' option. This is to prevent end users from shooting themselves in the foot by checking out files that Windows Explorer, cmd/bash or their favorite IDE cannot handle. Test suite: Test the case is when the full pathname length of a dir is close to 260 (MAX_PATH). Bug report and an original reproducer by Andrey Rogozhnikov: https://github.com/msysgit/git/pull/122#issuecomment-43604199 [jes: adjusted test number to avoid conflicts, added support for chdir(), etc] Thanks-to: Martin W. Kirst Thanks-to: Doug Kelly Original-test-by: Andrey Rogozhnikov Signed-off-by: Karsten Blees Signed-off-by: Stepan Kasal Signed-off-by: Johannes Schindelin Signed-off-by: Josh Soref