# 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
`$env.FOO = "BAR"`.
# Tests + Formatting
<!--
Don't forget to add tests that cover your changes.
Make sure you've run and fixed any issues with these commands:
- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect -A clippy::result_large_err` to check that
you're using the standard code style
- `cargo test --workspace` to check that all tests pass
- `cargo run -- crates/nu-std/tests/run.nu` to run the tests for the
standard library
> **Note**
> from `nushell` you can also use the `toolkit` as follows
> ```bash
> use toolkit.nu # or use an `env_change` hook to activate it
automatically
> toolkit check pr
> ```
-->
# After / Before Submitting
integration scripts to update:
- ✔️
[starship](https://github.com/starship/starship/blob/master/src/init/starship.nu)
- ✔️
[virtualenv](https://github.com/pypa/virtualenv/blob/main/src/virtualenv/activation/nushell/activate.nu)
- ✔️
[atuin](https://github.com/ellie/atuin/blob/main/atuin/src/shell/atuin.nu)
(PR: https://github.com/ellie/atuin/pull/1080)
- ❌
[zoxide](https://github.com/ajeetdsouza/zoxide/blob/main/templates/nushell.txt)
(PR: https://github.com/ajeetdsouza/zoxide/pull/587)
- ✔️
[oh-my-posh](https://github.com/JanDeDobbeleer/oh-my-posh/blob/main/src/shell/scripts/omp.nu)
(pr: https://github.com/JanDeDobbeleer/oh-my-posh/pull/4011)
I tackled some of the disabled `FIXME`/`#[ignore]` tests. Most were
straightforward to re-enable, and a few of them did not deserve to be
re-enabled.
---------
Co-authored-by: Darren Schroeder <343840+fdncred@users.noreply.github.com>
# Description
Purely for consistency, various remaining instances of `$nothing`
(almost all of which were in test code) have been changed to `null`.
Now, the only place that refers to `$nothing` is the parser code which
implements it.
# User-Facing Changes
The default config.nu now uses `null` in certain places where it used
`$nothing`.
# 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` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass
# After Submitting
If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.
* Allow environment variables to be hidden
This change allows environment variables in Nushell to have a value of
`Nothing`, which can be set by the user by passing `$nothing` to
`let-env` and friends.
Environment variables with a value of Nothing behave as if they are not
set at all. This allows a user to shadow the value of an environment
variable in a parent scope, effectively removing it from their current
scope. This was not possible before, because a scope can not affect its
parent scopes.
This is a workaround for issues like #3920.
Additionally, this allows a user to simultaneously set, change and
remove multiple environment variables via `load-env`. Any environment
variables set to $nothing will be hidden and thus act as if they are
removed. This simplifies working with virtual environments, which rely
on setting multiple environment variables, including PATH, to specific
values, and remove/change them on deactivation.
One surprising behavior is that an environment variable set to $nothing
will act as if it is not set when querying it (via $nu.env.X), but it is
still possible to remove it entirely via `unlet-env`. If the same
environment variable is present in the parent scope, the value in the
parent scope will be visible to the user. This might be surprising
behavior to users who are not familiar with the implementation details.
An additional corner case is the the shorthand form of `with-env` does
not work with this feature. Using `X=$nothing` will set $nu.env.X to the
string "$nothing". The long-form works as expected: `with-env [X
$nothing] {...}`.
* Remove unused import
* Allow all primitives to be convert to strings
* move commands, futures.rs, script.rs, utils
* move over maybe_print_errors
* add nu_command crate references to nu_cli
* in commands.rs open up to pub mod from pub(crate)
* nu-cli, nu-command, and nu tests are now passing
* cargo fmt
* clean up nu-cli/src/prelude.rs
* code cleanup
* for some reason lex.rs was not formatted, may be causing my error
* remove mod completion from lib.rs which was not being used along with quickcheck macros
* add in allow unused imports
* comment out one failing external test; comment out one failing internal test
* revert commenting out failing tests; something else might be going on; someone with a windows machine should check and see what is going on with these failing windows tests
* Update Cargo.toml
Extend the optional features to nu-command
Co-authored-by: Jonathan Turner <jonathandturner@users.noreply.github.com>
