nushell/crates/nu-command/src
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
..
bits add signature information when get help on one command (#7079) 2022-11-20 07:22:42 -06:00
bytes add signature information when get help on one command (#7079) 2022-11-20 07:22:42 -06:00
charting Split blocks and closures (#7075) 2022-11-10 21:21:49 +13:00
conversions add signature information when get help on one command (#7079) 2022-11-20 07:22:42 -06:00
core_commands Reorder export-env eval and allow reloading an overlay (#7231) 2022-11-24 23:45:24 +01:00
database Apply clippy fix (#7193) 2022-11-23 16:57:27 +13:00
dataframe Rename dataframe describe to summary so that the normal describe isn't overloaded (#7176) 2022-11-23 17:58:28 +01:00
date add signature information when get help on one command (#7079) 2022-11-20 07:22:42 -06:00
deprecated Rename all?, any? and empty? (#6464) 2022-09-05 16:41:06 +02:00
env Make external command substitution works friendly(like fish shell, trailing ending newlines) (#7156) 2022-11-23 16:51:57 +13:00
experimental Removes export env command (#6468) 2022-09-25 19:52:43 +03:00
filesystem Fix mv error message issues (arrows, Windows paths) (#7197) 2022-11-23 16:55:13 +13:00
filters New commands: break, continue, return, and loop (#7230) 2022-11-25 09:39:16 +13:00
formats Stdout/Stderr redirection (#7185) 2022-11-23 07:26:13 +13:00
generators Remove --separator from seq date (#7096) 2022-11-11 20:16:44 +13:00
hash add signature information when get help on one command (#7079) 2022-11-20 07:22:42 -06:00
math add signature information when get help on one command (#7079) 2022-11-20 07:22:42 -06:00
misc Replace all instances of 'column path' in help messages with 'cell path' (#7063) 2022-11-09 21:49:11 -08:00
network Fix fetch/post not erroring on 4xx and 5xx statuses (#7213) 2022-11-23 08:43:12 -08:00
path Fix sort-by, path join and size error arrows (#7199) 2022-11-23 19:22:23 +13:00
platform add signature information when get help on one command (#7079) 2022-11-20 07:22:42 -06:00
random add signature information when get help on one command (#7079) 2022-11-20 07:22:42 -06:00
shells Refactor shell listing related code (#6262) 2022-08-08 06:31:24 -05:00
strings Fix sort-by, path join and size error arrows (#7199) 2022-11-23 19:22:23 +13:00
system A set of fixes for stderr redirect (#7219) 2022-11-24 16:58:15 +13:00
viewers Apply clippy fix (#7193) 2022-11-23 16:57:27 +13:00
default_context.rs New commands: break, continue, return, and loop (#7230) 2022-11-25 09:39:16 +13:00
example_test.rs New commands: break, continue, return, and loop (#7230) 2022-11-25 09:39:16 +13:00
input_handler.rs Replace all instances of 'column path' in help messages with 'cell path' (#7063) 2022-11-09 21:49:11 -08:00
lib.rs Feature cleanup (#7182) 2022-11-22 16:58:11 -08:00
sort_utils.rs Fix sort-by, path join and size error arrows (#7199) 2022-11-23 19:22:23 +13:00