nushell/crates/nu-command/src/core_commands
Jakub Žádník 2388e1e80b
Reorder export-env eval and allow reloading an overlay (#7231)
# Description

This PR is a response to the issues raised in
https://github.com/nushell/nushell/pull/7087. It consists of two
changes:
* `export-env`, when evaluated in `overlay use`, will see the original
environment. Previously, it would see the environment from previous
overlay activation.
* Added a new `--reload` flag that reloads the overlay. Custom
definitions will be kept but the original definitions and environment
will be reloaded.

This enables a pattern when an overlay is supposed to shadow an existing
environment variable, such as `PROMPT_COMMAND`, but `overlay use` would
keep loading the value from the first activation. You can easily test it
by defining a module
```
module prompt {
    export-env {
        let-env PROMPT_COMMAND = (date now | into string)
    }
}
```
Calling `overlay use prompt` for the first time changes the prompt to
the current time, however, subsequent calls of `overlay use` won't
change the time. That's because overlays, once activated, store their
state so they can be hidden and restored at later time. To force-reload
the environment, use the new flag: Calling `overlay use --reload prompt`
repeatedly now updates the prompt with the current time each time.

# User-Facing Changes

* When calling `overlay use`, if the module has an `export-env` block,
the block will see the environment as it is _before_ the overlay is
activated. Previously, it was _after_.
* A new `overlay use --reload` flag.

# 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.
2022-11-24 23:45:24 +01:00
..
overlay Reorder export-env eval and allow reloading an overlay (#7231) 2022-11-24 23:45:24 +01:00
alias.rs Declare input and output types of commands (#6796) 2022-11-10 10:55:05 +13:00
ast.rs Declare input and output types of commands (#6796) 2022-11-10 10:55:05 +13:00
break_.rs New commands: break, continue, return, and loop (#7230) 2022-11-25 09:39:16 +13:00
commandline.rs Declare input and output types of commands (#6796) 2022-11-10 10:55:05 +13:00
continue_.rs New commands: break, continue, return, and loop (#7230) 2022-11-25 09:39:16 +13:00
debug.rs Declare input and output types of commands (#6796) 2022-11-10 10:55:05 +13:00
def_env.rs Split blocks and closures (#7075) 2022-11-10 21:21:49 +13:00
def.rs Split blocks and closures (#7075) 2022-11-10 21:21:49 +13:00
describe.rs Declare input and output types of commands (#6796) 2022-11-10 10:55:05 +13:00
do_.rs New commands: break, continue, return, and loop (#7230) 2022-11-25 09:39:16 +13:00
echo.rs Declare input and output types of commands (#6796) 2022-11-10 10:55:05 +13:00
error_make.rs Test command names and search terms for redundancy (#6380) 2022-08-24 11:16:47 +02:00
export_alias.rs Declare input and output types of commands (#6796) 2022-11-10 10:55:05 +13:00
export_def_env.rs Split blocks and closures (#7075) 2022-11-10 21:21:49 +13:00
export_def.rs Split blocks and closures (#7075) 2022-11-10 21:21:49 +13:00
export_extern.rs Declare input and output types of commands (#6796) 2022-11-10 10:55:05 +13:00
export_use.rs Declare input and output types of commands (#6796) 2022-11-10 10:55:05 +13:00
export.rs add signature information when get help on one command (#7079) 2022-11-20 07:22:42 -06:00
extern_.rs Declare input and output types of commands (#6796) 2022-11-10 10:55:05 +13:00
for_.rs New commands: break, continue, return, and loop (#7230) 2022-11-25 09:39:16 +13:00
help.rs add signature information when get help on one command (#7079) 2022-11-20 07:22:42 -06:00
hide_env.rs Declare input and output types of commands (#6796) 2022-11-10 10:55:05 +13:00
hide.rs Declare input and output types of commands (#6796) 2022-11-10 10:55:05 +13:00
if_.rs Split blocks and closures (#7075) 2022-11-10 21:21:49 +13:00
ignore.rs Declare input and output types of commands (#6796) 2022-11-10 10:55:05 +13:00
let_.rs Fix command_type classification (#7074) 2022-11-09 19:09:33 -08:00
loop_.rs New commands: break, continue, return, and loop (#7230) 2022-11-25 09:39:16 +13:00
metadata.rs to html --list now returns a table (#7080) 2022-11-15 11:12:56 -06:00
mod.rs New commands: break, continue, return, and loop (#7230) 2022-11-25 09:39:16 +13:00
module.rs Split blocks and closures (#7075) 2022-11-10 21:21:49 +13:00
mut_.rs Limited mutable variables (#7089) 2022-11-11 19:51:08 +13:00
register.rs Declare input and output types of commands (#6796) 2022-11-10 10:55:05 +13:00
return_.rs New commands: break, continue, return, and loop (#7230) 2022-11-25 09:39:16 +13:00
try_.rs Make catch block a closure w/ access to error (#7228) 2022-11-25 07:02:20 +13:00
use_.rs Declare input and output types of commands (#6796) 2022-11-10 10:55:05 +13:00
version.rs Feature cleanup (#7182) 2022-11-22 16:58:11 -08:00
while_.rs New commands: break, continue, return, and loop (#7230) 2022-11-25 09:39:16 +13:00