nushell/crates/nu-command
Antoine Stevan 6c026242d4
remove the $nothing variable (#10478)
related to 
- https://github.com/nushell/nushell/pull/9973
- https://github.com/nushell/nushell/pull/9918

thanks to @jntrnr and their super useful tips on this PR, i learned
about the parser + evaluation, so 🙏

# Description
because we already have `null` as the value of the type `nothing` and as
a followup to the two other attempts of mine, i propose to remove the
redundant `$nothing` built-in variable 😋

this PR is the first step, deprecating `$nothing`.
a followup PR will remove it altogether and wait for 0.87 👍 

⚙️ **details**: a new `NOTHING_VARIABLE_ID = 3` has been added,
parsing `$nothing` will create it, finally a `Value::Nothing` will be
produced and a warning will be reported.

this PR already fixes the `toolkit.nu` module so that it does not throw
a bunch of warnings each time 👌

# User-Facing Changes
`$nothing` is now deprecated and will be removed in 0.87
```nushell
> $nothing
Error:   × Deprecated variable
   ╭─[entry #1:1:1]
 1 │ $nothing
   · ────┬───
   ·     ╰── `$nothing` is deprecated and will be removed in 0.87.
   ╰────
  help: Use `null` instead
```

# Tests + Formatting
tests have been updated, especially
- `nothing_fails_string`
- `nothing_fails_int`
which use a variable called `nil` now to make sure `nothing` does not
support cell paths 👍

# After Submitting
classic deprecation mention 👍
2023-09-26 18:49:28 +02:00
..
src Bump dialoguer to 0.11.0 (#10510) 2023-09-26 18:00:16 +02:00
tests remove the $nothing variable (#10478) 2023-09-26 18:49:28 +02:00
Cargo.toml Bump dialoguer to 0.11.0 (#10510) 2023-09-26 18:00:16 +02:00
LICENSE Fix rest of license year ranges (#8727) 2023-04-04 09:03:29 +12:00