vim.json.decode(..., {luanil={object=false, array=false}}) replaces vim.NIL about neovim

[zeertzjq]

:h lua-table

Like indices, the value of a table field can be of any type (except `nil`). In
particular, because functions are first-class values, table fields may contain
functions. Thus tables may also carry methods (see |lua-function-define|).

[aktersnurra]

Then I suppose the documentation needs to be updated since it states:

:h vim.json.decode
vim.json.decode({str}, {opts})                             *vim.json.decode()*
    Decodes (or "unpacks") the JSON-encoded {str} to a Lua object.

    • Decodes JSON "null" as |vim.NIL| (controllable by {opts}, see below).
    • Decodes empty object as |vim.empty_dict()|.
    • Decodes empty array as `{}` (empty Lua table).

    Example: >lua
        vim.print(vim.json.decode('{"bar":[],"foo":{},"zub":null}'))
        -- { bar = {}, foo = vim.empty_dict(), zub = vim.NIL }
<

    Parameters: ~
      • {str}   (`string`) Stringified JSON data.
      • {opts}  (`table<string,any>?`) Options table with keys:
                • luanil: (table) Table with keys:
                  • object: (boolean) When true, converts `null` in JSON
                    objects to Lua `nil` instead of |vim.NIL|.
                  • array: (boolean) When true, converts `null` in JSON arrays
                    to Lua `nil` instead of |vim.NIL|.

[justinmk]

Then I suppose the documentation needs to be updated since it states:

Which part of the doc is wrong?

You can try your expected result directly in Lua, without involving vim.json.decode():

lua vim.print({ zub = nil, bar = {}, foo = vim.empty_dict() })

that prints:

{                                                                                                                                                                                                                    
  bar = {},                                                                                                                                                                                                          
  foo = vim.empty_dict()                                                                                                                                                                                             
}

Setting a table key to nil , removes the key.

[aktersnurra]

Yeah, you are right, the documentation is not wrong. It was my assumption of how it would work that was wrong, since I expected that lua-tables could hold nil values. So when I read this:

object: (boolean) When true, converts `null` in JSON
                    objects to Lua `nil` instead of |vim.NIL|.

I did not expect them to disappear.

But is it not strange that if I run this configuration:

vim.json.decode('{"bar":[],"foo":{},"zub":null}', { luanil = { object = false, array = false }})

I still get:

{
  bar = {},
  foo = vim.empty_dict()
}

Anyway, thanks for the help, much appreciated.

[justinmk]

But is it not strange that if I run this configuration:

vim.json.decode('{"bar":[],"foo":{},"zub":null}', { luanil = { object = false, array = false }})

I still get:

{
  bar = {},
  foo = vim.empty_dict()
}

that does seem like a bug

[zeertzjq]

It seems that these aren't actually boolean keys. Setting them to any value except nil behaves like true.

[zeertzjq]

Upstream doesn't have luanil. It's an Nvim addition.

[clason]

Yes, that was my point. But never mind.