Remove deprecated environment functionality

[WindSoilder]

Description

while reading https://hackmd.io/@nucore/r1zilyw6q to see what's the future about module environment, I sopt that most of thing are done.

And export env doesn't work with source-env command.

So this pr is trying to help to remove export env command, and adjust relative tests and examples

About three more ignored tests:

1. use_env_import_after_hide: it's more about hide-env, overlay, export-env commands
2. hides_all_envs_within_scope: it's more about hide-env, overlay, export-env commands
3. remove_overlay_keep_discard_overwritten_env: it's more about overlay with export-env issue itself, so I think it's ok to remove it

They are existing issue about the communication of overlay, export-env and hide-env commands, I think we can keep it ignored for now, and fix them in separate pr.
But I think it's also ok to wait these relative issue to be fixed firstly.

Tests

Make sure you've done the following:

• Add tests that cover your changes, either in the command examples, the crate/tests folder, or in the /tests folder.
• Try to think about corner cases and various ways how your changes could break. Cover them with tests.
• If adding tests is not possible, please document in the PR body a minimal example with steps on how to reproduce so one can verify your change works.

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 --features=extra -- -D warnings -D clippy::unwrap_used -A clippy::needless_collect to check that you're using the standard code style
• cargo test --workspace --features=extra to check that all the tests pass

[kubouch]

Thanks! I purposefully kept it in for the next release for compatibility reasons. We can land it after the next release.

[kubouch]

I'm not sure about the ignored tests. Could you try converting them to use the export-env and overlay use like the other tests? I'd like to see what errors they bring.

[kubouch]

Oh, and the whole "Cleanup" part from the hackmd I'm planning to do after the release so people have time to transition and fix their scripts until the next-next release.

[WindSoilder]

I'm not sure about the ignored tests. Could you try converting them to use the export-env and overlay use like the other tests? I'd like to see what errors they bring.

Actually I've converted them to use export-env and overlay use, but after manually testing, it doesn't work as test expected:

hides_all_envs_within_scope

> module spam { export-env { let-env foo = "bar" } }; let-env foo = "foo"; overlay use spam; hide-env foo; $env.foo
foo

It doesn't failed with did you mean message

use_env_import_after_hide

> module spam { export-env {let-env foo = "foo" } }; overlay use spam; hide-env foo; overlay use spam; $env.foo
Error: nu::shell::name_not_found (link)

  × Name not found
   ╭─[entry #1:1:1]
 1 │ module spam { export-env {let-env foo = "foo" } }; overlay use spam; hide-env foo; overlay use spam; $env.foo
   ·                                                                                                           ─┬─
   ·                                                                                                            ╰── did you mean 'HOME'?
   ╰────

It doesn't output foo.

remove_overlay_keep_discard_overwritten_env

❯ cat spam.nu
export def foo [] { "foo" }

export alias bar = "bar"

export-env { let-env BAZ = "baz" } }

~
❯ overlay use spam.nu; let-env BAZ = `bagr`; overlay hide --keep-custom spam; $env.BAZ
bagr

It doesn't failed with did you mean message

---

Oh, I forget update these ignored tests, updated it.

[kubouch]

@WindSoilder If you don't mind, I'll push some changes to your PR. I'd like to check the tests and also investigate the --keep-custom flag and it's easier to for me to fix up these things myself.

[kubouch]

I went through the tests again because the use command adopted the source-env functionality. I also finished all the environment cleanup.

The virtualenv tests are failing because hide no longer hides environment variables. We need to wait until pypa/virtualenv#2422 is merged.