Error executing lua callback: Vim:E976: using Blob as a String

[miversen33]

Received an error while opening a tar file in neovim. The following error:

Error detected while processing CursorMoved Autocommands for "*":
Error executing lua callback: Vim:E976: using Blob as a String
stack traceback:
        [C]: in function 'matchstr'
        ...ack/packer/start/nvim-cursorline/lua/nvim-cursorline.lua:27: in function 'matchadd'
        ...ack/packer/start/nvim-cursorline/lua/nvim-cursorline.lua:96: in function <...ack/packer/start/nvim-cursorline/lua/nvim-cursorline.lua:95>

Can be reliably recreated with the following command

mkdir test && echo "Hello World" > test/test.txt && tar -cf test.tar test && nvim test.tar

Basically, whenever Neovim opens a tar, it seems to have some string in there that cursorline doesn't know how to handle and thus it blows up.

Neovim Info

NVIM v0.8.0-dev-1008-g12fe197cf
Build type: RelWithDebInfo
LuaJIT 2.1.0-beta3
Compilation: /usr/bin/cc -DNVIM_TS_HAS_SET_MATCH_LIMIT -DNVIM_TS_HAS_SET_ALLOCATOR -O2 -g -Og -g -Wall -Wextra -pedantic -Wno-unused-parameter -Wstrict-prototypes -std=gnu99 -Wshadow -Wconversion -Wdouble-promotion -Wmissing-noreturn -Wmissing-format-attribute -Wmissing-prototypes -Wimplicit-fallthrough -Wvla -fstack-protector-strong -fno-common -fdiagnostics-color=always -DINCLUDE_GENERATED_DECLARATIONS -D_GNU_SOURCE -DNVIM_MSGPACK_HAS_FLOAT32 -DNVIM_UNIBI_HAS_VAR_FROM -DMIN_LOG_LEVEL=3 -I/home/miversen/git/neovim/build/cmake.config -I/home/miversen/git/neovim/src -I/home/miversen/git/neovim/.deps/usr/include -I/usr/include -I/home/miversen/git/neovim/build/src/nvim/auto -I/home/miversen/git/neovim/build/include
Compiled by miversen

Features: +acl +iconv +tui
See ":help feature-compile"

   system vimrc file: "$VIM/sysinit.vim"
  fall-back for $VIM: "/opt/neovim/share/nvim"

Run :checkhealth for more info

[miversen33]

Some more details, below is what is being displayed in the window when you open your file

^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@^@
" tar.vim version v32
" Browsing tarfile /home/miversen/tmp/test.tar
" Select a file with cursor and press ENTER

test/
test/test.txt

Note, ^@ is actually a Null Pointer. I am not completely certain why (I don't know tar spec that well and this could be coming from netrw) but the entire first line is made up of a ton of Null Pointers. When nvim-cursorline (or it seems most tools that read the lines your cursor is on) attempt to parse this, they die due to the aforementioned error I caught.

Not sure the best route to go here, maybe just wrap your function call in a pcall? Seems ick but it doesn't seem like there is a ton of options