Calling cmd.exe in Windows follows a very different pattern from Vim.
The primary difference is that Vim does a nested call to cmd.exe, e.g.
the following call in Vim
system('echo a 2>&1')
spawns the following processes
"C:\Program Files (x86)\Vim\vim80\vimrun" -s C:\Windows\system32\cmd.exe /c (echo a 2^>^&1
^>C:\Users\dummy\AppData\Local\Temp\VIoC169.tmp 2^>^&1)
C:\Windows\system32\cmd.exe /c C:\Windows\system32\cmd.exe /c (echo a 2^>^&1
^>C:\Users\dummy\AppData\Local\Temp\VIo3C6C.tmp 2^>^&1)
C:\Windows\system32\cmd.exe /c (echo a 2>&1
>C:\Users\dummy\AppData\Local\Temp\VIo3C6C.tmp 2>&1)
The escaping with ^ is needed because cmd.exe calls itself and needs to
preserve the special metacharacters for the last call. However in nvim
no nested call is made, system('') spawns a single cmd.exe process.
Setting shellxescape to "" disables escaping with ^.
The previous default for shellxquote=( wrapped any command in
parenthesis, in Vim this is more meaningful due to the use of tempfiles
to store the output and redirection (also see &shellquote). There is
a slight benefit in having the default be empty because some expressions
that run in console will not run within parens e.g. due to unbalanced
double quotes
system('echo "a b')
Disable CommandLineToArgvW-standard quoting for cmd.exe.
libuv assumes spawned processes follow the convention expected by
CommandLineToArgvW(). But cmd.exe is non-conformant, so for cmd.exe:
- With system([]), the caller has full control (and responsibility) to
quote arguments correctly.
- With system(''), shell* options are used.
libuv quoting is disabled if argv[0] is:
- cmd.exe
- cmd
- $COMSPEC resolving to a path with filename cmd.exe
Closes#6329
References #6387
Should not really change anything, but code should be more efficient by using
more optimized libc functions (memchrsub is not libc, but it uses memchr) in
place of a cycle.
Reasoning is majorly the same: check whether lua has bug or API function has
bug, but on the other side: previous commit is checking whether similar bug when
using API via msgpack RPC, this commit is checking whether another API function
used via lua bindings triggers the same bug. Should additionally give a hint
about which lua code contains a bug.
On Windows, `mch_open_rw` is not actually doing what it claims. This
manifests as "E301: Oops, lost the swap file !!!" when filename is
changed with :file {name}.
Steps to reproduce (covered by test/functional/ex_cmds/file_spec.lua):
nvim -u NONE
:edit test
:file test2
E301 Oops, lost the swap file!!!
From libuv/src/win/fs.c:
void fs__open(uv_fs_t* req) {
...
attributes |= FILE_ATTRIBUTE_NORMAL;
if (flags & _O_CREAT) {
if (!((req->fs.info.mode & ~current_umask) & _S_IWRITE)) {
attributes |= FILE_ATTRIBUTE_READONLY;
}
}
Lua has too many pitfalls here:
- os.execute() requires shell-escaping
- os.execute() has breaking changes between Lua 5.1 and 5.2
- No native way in Lua to handle "readonly" etc. on Windows
