nushell/tests/shell/environment/env.rs
Douglas 00709fc5bd
Improves startup time when using std-lib (#13842)
Updated summary for commit
[612e0e2](612e0e2160)
- While folks are welcome to read through the entire comments, the core
information is summarized here.

# Description

This PR drastically improves startup times of Nushell by only parsing a
single submodule of the Standard Library that provides the `banner` and
`pwd` commands. All other Standard Library commands and submodules are
parsed when imported by the user. This cuts startup times by more than
60%.

At the moment, we have stopped adding to `std-lib` because every
addition adds a small amount to the Nushell startup time.
With this change, we should once again be able to allow new
functionality to be added to the Standard Library without it impacting
`nu` startup times.

# User-Facing Changes

* Nushell now starts about 60% faster
* Breaking change: The `dirs` (Shells) aliases will return a warning
message that it will not be auto-loaded in the following release, along
with instructions on how to restore it (and disable the message)
* The `use std <submodule> *` syntax is available for convenience, but
should be avoided in scripts as it parses the entire `std` module and
all other submodules and places it in scope. The correct syntax to
*just* load a submodule is `use std/<submodule> *` (asterisk optional).
The slash is important. This will be documented.
* `use std *` can be used for convenience to load all of the library but
still incurs the full loading-time.
* `std/dirs`: Semi-breaking change. The `dirs` command replaces the
`show` command. This is more in line with the directory-stack
functionality found in other shells. Existing users will not be impacted
by this as the alias (`shells`) remains the same.

* Breaking-change: Technically a breaking change, but probably only
impacts maintainers of `std`. The virtual path for the standard library
has changed. It could previously be imported using its virtual path (and
technically, this would have been the correct way to do it):

  ```nu
  use NU_STDLIB_VIRTUAL_DIR/std
  ```

  The path is now simply `std/`:

  ```nu
  use std
  ```

  All submodules have moved accordingly.
  

# Timings

Comparisons below were made:

* In a temporary, clean config directory using `$env.XDG_CONFIG_HOME =
(mktemp -d)`.
* `nu` was run with a release build
* `nu` was run one time to generate the default `config.nu` (etc.) files
- Otherwise timings would include the user-prompt
* The shell was exited and then restarted several times to get timing
samples

(Note: Old timings based on 0.97 rather than 0.98, but in the range of
being accurate)

| Scenario | `$nu.startup-time` |
| --- | --- |
| 0.97.2
([aaaab8e](aaaab8e070))
Without this PR | 23ms - 24ms |
| This PR with deprecated commands | 9ms - <11ms |
| This PR after deprecated commands are removed in following release |
8ms - <10ms |
| Final PR (remove deprecated), using `--no-std-lib` | 6.1ms to 6.4ms |
| Final PR (remove deprecated), using `--no-config-file` | 3.1ms - 3.6ms
|
| Final PR (remove deprecated), using `--no-config-file --no-std-lib` |
1ms - 1.5ms |

*These last two timings point to the opportunity for further
optimization (see comment in thread below (will link once I write it).*

# Implementation details for future maintenance

* `use std banner` is a ridiculously deceptive call. That call parses
and imports *all* of `std` into scope. Simply replacing it with `use
std/core *` is essentially what saves ~14-15ms. This *only* imports the
submodule with the `banner` and `pwd` commands.

* From the code-comments, the reason that `NU_STDLIB_VIRTUAL_DIR` was
used as a prefix was so that there wouldn't be an issue if a user had a
`./std/mod.nu` in the current directory. This does **not** appear to be
an issue. After removing the prefix, I tested with both a relative
module as well as one in the `$env.NU_LIB_DIRS` path, and in all cases
the *internal* `std` still took precedence.

* By removing the prefix, users can now `use std` (and variants) without
requiring that it already be parsed and in scope.

* In the next release, we'll stop autoloading the `dirs` (shells)
functionality. While this only costs an additional 1-1.5ms, I think it's
better moved to the `config.nu` where the user can optionally remove it.
The main reason is its use of aliases (which have also caused issues) -
The `n`, `p`, and `g` short-commands are valuable real-estate, and users
may want to map these to something else.
  
For this release, there's an `deprecated_dirs` module that is still
autoloaded. As with the top-level commands, use of these will give a
deprecation warning with instructions on how to handle going forward.

To help with this, moved the aliases to their own submodule inside the
`dirs` module.

* Also sneaks in a small change where the top-level `dirs` command is
now the replacement for `dirs show`

* Fixed a double-import of `assert` in `dirs.nu`
* The `show_banner` step is replaced with simply `banner` rather than
re-importing it.

* A `virtual_path` may now be referenced with either a forward-slash or
a backward-slash on Windows. This allows `use std/<submodule>` to work
on all platforms.

# Performance side-notes:

* Future parsing and/or IR improvements should improve performance even
further.
* While the existing load time penalty of `std-lib` was not noticeable
on many systems, Nushell runs on a wide-variety of hardware and OS
platforms. Slower platforms will naturally see a bigger jump in
performance here. For users starting multiple Nushell sessions
frequently (e.g., `tmux`, Zellij, `screen`, et. al.) it is recommended
to keep total startup time (including user configuration) under ~250ms.

# Tests + Formatting

* All tests are green

* Updated tests:
- Removed the test that confirmed that `std` was loaded (since we
don't).
- Removed the `shells` test since it is not autoloaded. Main `dirs.nu`
functionality is tested through `stdlib-test`.
- Many tests assumed that the library was fully loaded, because it was
(even though we didn't intend for it to be). Fixed those tests.
- Tests now import only the necessary submodules (e.g., `use
std/assert`, rather than `use std assert`)
- Some tests *thought* they were loading `std/log`, but were doing so
improperly. This was masked by the now-fixed "load-everything-into-scope
bug". Local CI would pass due the `$env.NU_LOG_<...>` variables being
inherited from the calling process, but would fail in the "clean" GitHub
CI environment. These tests have also been fixed.

 * Added additional tests for the changes

# After Submitting

Will update the Standard Library doc page
2024-10-03 06:28:22 -05:00

248 lines
5.9 KiB
Rust

use super::support::Trusted;
use nu_test_support::fs::Stub::FileWithContent;
use nu_test_support::playground::Playground;
use nu_test_support::{nu, nu_repl_code, nu_with_std};
use pretty_assertions::assert_eq;
use serial_test::serial;
#[test]
fn env_shorthand() {
let actual = nu!("
FOO=bar echo $env.FOO
");
assert_eq!(actual.out, "bar");
}
#[test]
fn env_shorthand_with_equals() {
let actual = nu!("
RUST_LOG=my_module=info $env.RUST_LOG
");
assert_eq!(actual.out, "my_module=info");
}
#[test]
fn env_shorthand_with_interpolation() {
let actual = nu!(r#"
let num = 123
FOO=$"($num) bar" echo $env.FOO
"#);
assert_eq!(actual.out, "123 bar");
}
#[test]
fn env_shorthand_with_comma_equals() {
let actual = nu!("
RUST_LOG=info,my_module=info $env.RUST_LOG
");
assert_eq!(actual.out, "info,my_module=info");
}
#[test]
fn env_shorthand_with_comma_colons_equals() {
let actual = nu!("
RUST_LOG=info,my_module=info,lib_crate::lib_mod=trace $env.RUST_LOG
");
assert_eq!(actual.out, "info,my_module=info,lib_crate::lib_mod=trace");
}
#[test]
fn env_shorthand_multi_second_with_comma_colons_equals() {
let actual = nu!("
FOO=bar RUST_LOG=info,my_module=info,lib_crate::lib_mod=trace $env.FOO + $env.RUST_LOG
");
assert_eq!(
actual.out,
"barinfo,my_module=info,lib_crate::lib_mod=trace"
);
}
#[test]
fn env_shorthand_multi_first_with_comma_colons_equals() {
let actual = nu!("
RUST_LOG=info,my_module=info,lib_crate::lib_mod=trace FOO=bar $env.FOO + $env.RUST_LOG
");
assert_eq!(
actual.out,
"barinfo,my_module=info,lib_crate::lib_mod=trace"
);
}
#[test]
fn env_shorthand_multi() {
let actual = nu!("
FOO=bar BAR=baz $env.FOO + $env.BAR
");
assert_eq!(actual.out, "barbaz");
}
#[test]
fn env_assignment() {
let actual = nu!(r#"
$env.FOOBAR = "barbaz"; $env.FOOBAR
"#);
assert_eq!(actual.out, "barbaz");
}
#[test]
fn env_assignment_with_if() {
let actual = nu!(r#"$env.FOOBAR = if 3 == 4 { "bar" } else { "baz" }; $env.FOOBAR"#);
assert_eq!(actual.out, "baz");
}
#[test]
fn env_assignment_with_match() {
let actual = nu!(r#"$env.FOOBAR = match 1 { 1 => { 'yes!' }, _ => { 'no!' } }; $env.FOOBAR"#);
assert_eq!(actual.out, "yes!");
}
#[test]
fn mutate_env_file_pwd_env_var_fails() {
let actual = nu!("$env.FILE_PWD = 'foo'");
assert!(actual.err.contains("automatic_env_var_set_manually"));
}
#[test]
fn load_env_file_pwd_env_var_fails() {
let actual = nu!("load-env { FILE_PWD : 'foo' }");
assert!(actual.err.contains("automatic_env_var_set_manually"));
}
#[test]
fn load_env_pwd_env_var_fails() {
let actual = nu!("load-env { PWD : 'foo' }");
assert!(actual.err.contains("automatic_env_var_set_manually"));
}
#[test]
fn passes_with_env_env_var_to_external_process() {
let actual = nu!("
with-env { FOO: foo } {nu --testbin echo_env FOO}
");
assert_eq!(actual.out, "foo");
}
#[test]
fn hides_environment_from_child() {
let actual = nu!(r#"
$env.TEST = 1; ^$nu.current-exe -c "hide-env TEST; ^$nu.current-exe -c '$env.TEST'"
"#);
assert!(actual.out.is_empty());
assert!(actual.err.contains("column_not_found") || actual.err.contains("name_not_found"));
}
#[test]
fn has_file_pwd() {
Playground::setup("has_file_pwd", |dirs, sandbox| {
sandbox.with_files(&[FileWithContent("spam.nu", "$env.FILE_PWD")]);
let actual = nu!(cwd: dirs.test(), "nu spam.nu");
assert!(actual.out.ends_with("has_file_pwd"));
})
}
#[test]
fn has_file_loc() {
Playground::setup("has_file_pwd", |dirs, sandbox| {
sandbox.with_files(&[FileWithContent("spam.nu", "$env.CURRENT_FILE")]);
let actual = nu!(cwd: dirs.test(), "nu spam.nu");
assert!(actual.out.ends_with("spam.nu"));
})
}
// FIXME: autoenv not currently implemented
#[ignore]
#[test]
#[serial]
fn passes_env_from_local_cfg_to_external_process() {
Playground::setup("autoenv_dir", |dirs, sandbox| {
sandbox.with_files(&[FileWithContent(
".nu-env",
r#"[env]
FOO = "foo"
"#,
)]);
let actual = Trusted::in_path(&dirs, || {
nu!(cwd: dirs.test(), "
nu --testbin echo_env FOO
")
});
assert_eq!(actual.out, "foo");
})
}
#[test]
fn hides_env_in_block() {
let inp = &[
"$env.foo = 'foo'",
"hide-env foo",
"let b = {|| $env.foo }",
"do $b",
];
let actual = nu!(&inp.join("; "));
let actual_repl = nu!(nu_repl_code(inp));
assert!(actual.err.contains("column_not_found"));
assert!(actual_repl.err.contains("column_not_found"));
}
#[test]
fn env_var_not_var() {
let actual = nu!("
echo $PWD
");
assert!(actual.err.contains("use $env.PWD instead of $PWD"));
}
#[test]
fn env_var_case_insensitive() {
let actual = nu!("
$env.foo = 111
print $env.Foo
$env.FOO = 222
print $env.foo
");
assert!(actual.out.contains("111"));
assert!(actual.out.contains("222"));
}
#[test]
fn std_log_env_vars_are_not_overridden() {
let actual = nu_with_std!(
envs: vec![
("NU_LOG_FORMAT".to_string(), "%MSG%".to_string()),
("NU_LOG_DATE_FORMAT".to_string(), "%Y".to_string()),
],
r#"
use std/log
print -e $env.NU_LOG_FORMAT
print -e $env.NU_LOG_DATE_FORMAT
log error "err"
"#
);
assert_eq!(actual.err, "%MSG%\n%Y\nerr\n");
}
#[test]
fn std_log_env_vars_have_defaults() {
let actual = nu_with_std!(
r#"
use std/log
print -e $env.NU_LOG_FORMAT
print -e $env.NU_LOG_DATE_FORMAT
"#
);
assert!(actual.err.contains("%MSG%"));
assert!(actual.err.contains("%Y-"));
}