Vim error: Unable to open swap file when using backslash as path separator in Windows shell

Question

I'm using cmder as my Win7 shell. I see the following behaviour:

Works fine (file in current directory):

vim test

Works fine (absolute path):

vim ~/test

Works fine (relative path with forward slash):

vim subdir/test

Does not work fine (relative path with backward slash):

vim subdir\test

The last example flashes the following in vim:

E303: Unable to open swap file for "subdir\test", recovery impossible.

Doing :set dir shows:

directory=~/vimswap

which exists and is permissioned correctly (after all, I don't get errors when opening absolute path files, only relative path ones).

I suspect this might have something to do with how cmder/vim represent relative paths - maybe a forward slash/backslash issue?

Answer 1

I had this same problem and tracked it to the following.

I had set the following in vimrc

set backupdir=~/.vim/backup
set directory=~/.vim/tmp

But to make my work easier, I change the definition of HOME all the time.

When I did this, the ~ did not evaluate to a directory that had .vim/backup nor .vim/tmp in it. Hence, I got the error.

I changed the ~ to a fixed location and the problem went away.

This was under cygwin/Windows 11

Answer 2

The issue comes from Clink. A script has been submitted on their github, and Keith Milligan explains how to apply it:

Internally, cmder uses a utility called clink to enable bash-style command-line completion (and other things). You can enable forward-slash as a path separator, but adding some additional clink configuration to your cmder setup. If it does not exist, create cmder.lua in the config directory where you installed cmder. Add the following code:

local function force_fwd_slashes(text, first, last)
    clink.slash_translation(1)
    return false
end
clink.register_match_generator(force_fwd_slashes, -1)

Save the file and restart cmder. Paths will now be completed using forward slashes instead of backslashes.