nushell/crates/nu-command/src/debug
JT 4af24363c2
remove let-env, focus on mutating $env (#9574)
# Description

For years, Nushell has used `let-env` to set a single environment
variable. As our work on scoping continued, we refined what it meant for
a variable to be in scope using `let` but never updated how `let-env`
would work. Instead, `let-env` confusingly created mutations to the
command's copy of `$env`.

So, to help fix the mental model and point people to the right way of
thinking about what changing the environment means, this PR removes
`let-env` to encourage people to think of it as updating the command's
environment variable via mutation.

Before:

```
let-env FOO = "BAR"
```

Now:

```
$env.FOO = "BAR"
```

It's also a good reminder that the environment owned by the command is
in the `$env` variable rather than global like it is in other shells.

# User-Facing Changes

BREAKING CHANGE BREAKING CHANGE

This completely removes `let-env FOO = "BAR"` so that we can focus on
`$env.FOO = "BAR"`.

# Tests + Formatting
<!--
Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect -A clippy::result_large_err` to check that
you're using the standard code style
- `cargo test --workspace` to check that all tests pass
- `cargo run -- crates/nu-std/tests/run.nu` to run the tests for the
standard library

> **Note**
> from `nushell` you can also use the `toolkit` as follows
> ```bash
> use toolkit.nu # or use an `env_change` hook to activate it
automatically
> toolkit check pr
> ```
-->

# After / Before Submitting
integration scripts to update:
- ✔️
[starship](https://github.com/starship/starship/blob/master/src/init/starship.nu)
- ✔️
[virtualenv](https://github.com/pypa/virtualenv/blob/main/src/virtualenv/activation/nushell/activate.nu)
- ✔️
[atuin](https://github.com/ellie/atuin/blob/main/atuin/src/shell/atuin.nu)
(PR: https://github.com/ellie/atuin/pull/1080)
- 
[zoxide](https://github.com/ajeetdsouza/zoxide/blob/main/templates/nushell.txt)
(PR: https://github.com/ajeetdsouza/zoxide/pull/587)
- ✔️
[oh-my-posh](https://github.com/JanDeDobbeleer/oh-my-posh/blob/main/src/shell/scripts/omp.nu)
(pr: https://github.com/JanDeDobbeleer/oh-my-posh/pull/4011)
2023-07-01 07:57:51 +12:00
..
ast.rs update ast to support output to json (#8962) 2023-04-26 08:15:42 -05:00
debug_.rs Require that values that look like numbers parse as numberlike (#8635) 2023-03-28 19:31:38 +13:00
explain.rs Apply nightly clippy fixes (#9381) 2023-06-08 18:49:58 +02:00
inspect.rs throw an error instead of a panic if no input is provided to inspect (#9259) 2023-05-22 13:54:04 -05:00
inspect_table.rs Bump tabled dependency to 0.11 (#8922) 2023-04-26 13:56:10 -05:00
metadata.rs Uniformize usage() and extra_usage() message ending for commands helper. (#8268) 2023-02-28 21:33:02 -08:00
mod.rs move ast command to the debug group (#8077) 2023-02-14 18:47:34 +00:00
profile.rs Update some help examples (#8759) 2023-04-05 18:36:00 -05:00
timeit.rs Make timeit work with command calls (#8594) 2023-03-24 22:34:03 +13:00
view.rs Uniformize usage() and extra_usage() message ending for commands helper. (#8268) 2023-02-28 21:33:02 -08:00
view_files.rs Uniformize usage() and extra_usage() message ending for commands helper. (#8268) 2023-02-28 21:33:02 -08:00
view_source.rs remove let-env, focus on mutating $env (#9574) 2023-07-01 07:57:51 +12:00
view_span.rs Uniformize usage() and extra_usage() message ending for commands helper. (#8268) 2023-02-28 21:33:02 -08:00