json_encode() assert false on c0 or c1 utf-8 chars

[altermo]

Problem

When passing a c0 or c1 UTF-8 char (except for \xc0\x80) to json_encode() it will make an assert fail (if neovim is built with debug).

(c0 and c1 UTF-8 characters are the extended versions of the normal ascii characters and are considered invalid (though vim and neovim sometimes handle them fine))

Steps to reproduce

nvim --clean
:echo json_encode("\xc0\x81")

Expected behavior

Don't fail assert.

Neovim version (nvim -v)

v0.10.0-dev-c18d794 (built with Debug)

Vim (not Nvim) behaves the same?

no, vim 9.1

Operating system/version

linux 6.8.9-arch1-2

Terminal name/version

kitty 0.33.1

$TERM environment variable

xterm-kitty

Installation

build from repo

[justinmk]

vim.json.encode("\xc0\x81") seems to work. We should consider changing json_encode / json_decode so that they simply call vim.json.