nushell/tests
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
..
assets/nu_json Remove old nushell/merge engine-q 2022-02-07 14:54:06 -05:00
fixtures Support Arrow IPC file format with dataframes (#6548) 2022-09-12 18:30:20 -05:00
hooks Move from source to source-env (#6277) 2022-09-01 08:32:56 +12:00
modules Disable cyclical module imports (#6477) 2022-09-04 23:19:20 +03:00
overlays Reorder export-env eval and allow reloading an overlay (#7231) 2022-11-24 23:45:24 +01:00
parsing Change parser cwd when running a file (#7134) 2022-11-15 00:05:27 +01:00
path Run a round of clippy --fix to fix a ton of lints (#7006) 2022-11-04 15:11:17 -05:00
plugins Feature cleanup (#7182) 2022-11-22 16:58:11 -08:00
scope Fix reporting of which and $nu.scope (#4836) 2022-03-13 21:32:46 +02:00
shell Make external command substitution works friendly(like fish shell, trailing ending newlines) (#7156) 2022-11-23 16:51:57 +13:00
main.rs Fix file lookup in parser keywords; Refactor nu_repl (#6185) 2022-07-29 23:42:00 +03:00