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)
This commit is contained in:
JT
2023-07-01 07:57:51 +12:00
committed by GitHub
parent 11132f7353
commit 4af24363c2
51 changed files with 371 additions and 402 deletions

View File

@ -17,8 +17,8 @@
# This situation could arise if we started with [/a, /b, /c], then
# we changed directories from /b to /var/tmp.
export-env {
let-env DIRS_POSITION = 0
let-env DIRS_LIST = [($env.PWD | path expand)]
$env.DIRS_POSITION = 0
$env.DIRS_LIST = [($env.PWD | path expand)]
}
# Add one or more directories to the list.
@ -36,7 +36,7 @@ export def-env add [
$abspaths = ($abspaths | append $exp)
}
let-env DIRS_LIST = ($env.DIRS_LIST | insert ($env.DIRS_POSITION + 1) $abspaths | flatten)
$env.DIRS_LIST = ($env.DIRS_LIST | insert ($env.DIRS_POSITION + 1) $abspaths | flatten)
_fetch 1
@ -66,7 +66,7 @@ export alias p = prev
# PWD becomes the next working directory
export def-env drop [] {
if ($env.DIRS_LIST | length) > 1 {
let-env DIRS_LIST = ($env.DIRS_LIST | reject $env.DIRS_POSITION)
$env.DIRS_LIST = ($env.DIRS_LIST | reject $env.DIRS_POSITION)
if ($env.DIRS_POSITION >= ($env.DIRS_LIST | length)) {$env.DIRS_POSITION = 0}
}
@ -111,7 +111,7 @@ export def-env goto [shell?: int] {
}
}
}
let-env DIRS_POSITION = $shell
$env.DIRS_POSITION = $shell
cd ($env.DIRS_LIST | get $env.DIRS_POSITION)
}

View File

@ -164,7 +164,7 @@ def build-module-page [module: record] {
# > export def baz [] { "foo::baz" }
# >
# > export-env {
# > let-env FOO = "foo::FOO"
# > $env.FOO = "foo::FOO"
# > }
# > }
# >
@ -174,7 +174,7 @@ def build-module-page [module: record] {
# > export def baz [] { "bar::baz" }
# >
# > export-env {
# > let-env BAR = "bar::BAR"
# > $env.BAR = "bar::BAR"
# > }
# > }
# >
@ -184,7 +184,7 @@ def build-module-page [module: record] {
# > export def bar [] { "baz::bar" }
# >
# > export-env {
# > let-env BAZ = "baz::BAZ"
# > $env.BAZ = "baz::BAZ"
# > }
# > }
# > ```
@ -223,7 +223,7 @@ def build-module-page [module: record] {
#
# This module exports environment.
# {
# let-env FOO = "foo::FOO"
# $env.FOO = "foo::FOO"
# }
#
# search for a module that does not exist

View File

@ -1,5 +1,5 @@
export-env {
let-env LOG_ANSI = {
$env.LOG_ANSI = {
"CRITICAL": (ansi red_bold),
"ERROR": (ansi red),
"WARNING": (ansi yellow),
@ -7,7 +7,7 @@ export-env {
"DEBUG": (ansi default_dimmed)
}
let-env LOG_LEVEL = {
$env.LOG_LEVEL = {
"CRITICAL": 50,
"ERROR": 40,
"WARNING": 30,
@ -15,7 +15,7 @@ export-env {
"DEBUG": 10
}
let-env LOG_PREFIX = {
$env.LOG_PREFIX = {
"CRITICAL": "CRT",
"ERROR": "ERR",
"WARNING": "WRN",
@ -23,7 +23,7 @@ export-env {
"DEBUG": "DBG"
}
let-env LOG_SHORT_PREFIX = {
$env.LOG_SHORT_PREFIX = {
"CRITICAL": "C",
"ERROR": "E",
"WARNING": "W",
@ -31,7 +31,7 @@ export-env {
"DEBUG": "D"
}
let-env LOG_FORMAT = $"%ANSI_START%%DATE%|%LEVEL%|(ansi u)%MSG%%ANSI_STOP%"
$env.LOG_FORMAT = $"%ANSI_START%%DATE%|%LEVEL%|(ansi u)%MSG%%ANSI_STOP%"
}
def log-types [] {

View File

@ -68,12 +68,12 @@ export def-env "path add" [
}}
}
let-env $path_name = (
$env
| get $path_name
| if $append { append $paths }
else { prepend $paths }
)
load-env {$path_name: (
$env
| get $path_name
| if $append { append $paths }
else { prepend $paths }
)}
if $ret {
$env | get $path_name