nushell/crates/nu-cli/tests/support/completions_helpers.rs
Ian Manske b6c7656194
IO and redirection overhaul (#11934)
# Description
The PR overhauls how IO redirection is handled, allowing more explicit
and fine-grain control over `stdout` and `stderr` output as well as more
efficient IO and piping.

To summarize the changes in this PR:
- Added a new `IoStream` type to indicate the intended destination for a
pipeline element's `stdout` and `stderr`.
- The `stdout` and `stderr` `IoStream`s are stored in the `Stack` and to
avoid adding 6 additional arguments to every eval function and
`Command::run`. The `stdout` and `stderr` streams can be temporarily
overwritten through functions on `Stack` and these functions will return
a guard that restores the original `stdout` and `stderr` when dropped.
- In the AST, redirections are now directly part of a `PipelineElement`
as a `Option<Redirection>` field instead of having multiple different
`PipelineElement` enum variants for each kind of redirection. This
required changes to the parser, mainly in `lite_parser.rs`.
- `Command`s can also set a `IoStream` override/redirection which will
apply to the previous command in the pipeline. This is used, for
example, in `ignore` to allow the previous external command to have its
stdout redirected to `Stdio::null()` at spawn time. In contrast, the
current implementation has to create an os pipe and manually consume the
output on nushell's side. File and pipe redirections (`o>`, `e>`, `e>|`,
etc.) have precedence over overrides from commands.

This PR improves piping and IO speed, partially addressing #10763. Using
the `throughput` command from that issue, this PR gives the following
speedup on my setup for the commands below:
| Command | Before (MB/s) | After (MB/s) | Bash (MB/s) |
| --------------------------- | -------------:| ------------:|
-----------:|
| `throughput o> /dev/null` | 1169 | 52938 | 54305 |
| `throughput \| ignore` | 840 | 55438 | N/A |
| `throughput \| null` | Error | 53617 | N/A |
| `throughput \| rg 'x'` | 1165 | 3049 | 3736 |
| `(throughput) \| rg 'x'` | 810 | 3085 | 3815 |

(Numbers above are the median samples for throughput)

This PR also paves the way to refactor our `ExternalStream` handling in
the various commands. For example, this PR already fixes the following
code:
```nushell
^sh -c 'echo -n "hello "; sleep 0; echo "world"' | find "hello world"
```
This returns an empty list on 0.90.1 and returns a highlighted "hello
world" on this PR.

Since the `stdout` and `stderr` `IoStream`s are available to commands
when they are run, then this unlocks the potential for more convenient
behavior. E.g., the `find` command can disable its ansi highlighting if
it detects that the output `IoStream` is not the terminal. Knowing the
output streams will also allow background job output to be redirected
more easily and efficiently.

# User-Facing Changes
- External commands returned from closures will be collected (in most
cases):
  ```nushell
  1..2 | each {|_| nu -c "print a" }
  ```
This gives `["a", "a"]` on this PR, whereas this used to print "a\na\n"
and then return an empty list.

  ```nushell
  1..2 | each {|_| nu -c "print -e a" }
  ```
This gives `["", ""]` and prints "a\na\n" to stderr, whereas this used
to return an empty list and print "a\na\n" to stderr.

- Trailing new lines are always trimmed for external commands when
piping into internal commands or collecting it as a value. (Failure to
decode the output as utf-8 will keep the trailing newline for the last
binary value.) In the current nushell version, the following three code
snippets differ only in parenthesis placement, but they all also have
different outputs:

  1. `1..2 | each { ^echo a }`
     ```
     a
     a
     ╭────────────╮
     │ empty list │
     ╰────────────╯
     ```
  2. `1..2 | each { (^echo a) }`
     ```
     ╭───┬───╮
     │ 0 │ a │
     │ 1 │ a │
     ╰───┴───╯
     ```
  3. `1..2 | (each { ^echo a })`
     ```
     ╭───┬───╮
     │ 0 │ a │
     │   │   │
     │ 1 │ a │
     │   │   │
     ╰───┴───╯
     ```

  But in this PR, the above snippets will all have the same output:
  ```
  ╭───┬───╮
  │ 0 │ a │
  │ 1 │ a │
  ╰───┴───╯
  ```

- All existing flags on `run-external` are now deprecated.

- File redirections now apply to all commands inside a code block:
  ```nushell
  (nu -c "print -e a"; nu -c "print -e b") e> test.out
  ```
This gives "a\nb\n" in `test.out` and prints nothing. The same result
would happen when printing to stdout and using a `o>` file redirection.

- External command output will (almost) never be ignored, and ignoring
output must be explicit now:
  ```nushell
  (^echo a; ^echo b)
  ```
This prints "a\nb\n", whereas this used to print only "b\n". This only
applies to external commands; values and internal commands not in return
position will not print anything (e.g., `(echo a; echo b)` still only
prints "b").

- `complete` now always captures stderr (`do` is not necessary).

# After Submitting
The language guide and other documentation will need to be updated.
2024-03-14 15:51:55 -05:00

210 lines
5.8 KiB
Rust

use std::path::PathBuf;
use nu_engine::eval_block;
use nu_parser::parse;
use nu_protocol::debugger::WithoutDebug;
use nu_protocol::{
engine::{EngineState, Stack, StateWorkingSet},
eval_const::create_nu_constant,
PipelineData, ShellError, Span, Value, NU_VARIABLE_ID,
};
use nu_test_support::fs;
use reedline::Suggestion;
const SEP: char = std::path::MAIN_SEPARATOR;
fn create_default_context() -> EngineState {
nu_command::add_shell_command_context(nu_cmd_lang::create_default_context())
}
// creates a new engine with the current path into the completions fixtures folder
pub fn new_engine() -> (PathBuf, String, EngineState, Stack) {
// Target folder inside assets
let dir = fs::fixtures().join("completions");
let mut dir_str = dir
.clone()
.into_os_string()
.into_string()
.unwrap_or_default();
dir_str.push(SEP);
// Create a new engine with default context
let mut engine_state = create_default_context();
// Add $nu
let nu_const =
create_nu_constant(&engine_state, Span::test_data()).expect("Failed creating $nu");
engine_state.set_variable_const_val(NU_VARIABLE_ID, nu_const);
// New stack
let mut stack = Stack::new();
// Add pwd as env var
stack.add_env_var(
"PWD".to_string(),
Value::string(dir_str.clone(), nu_protocol::Span::new(0, dir_str.len())),
);
stack.add_env_var(
"TEST".to_string(),
Value::string(
"NUSHELL".to_string(),
nu_protocol::Span::new(0, dir_str.len()),
),
);
#[cfg(windows)]
stack.add_env_var(
"Path".to_string(),
Value::string(
"c:\\some\\path;c:\\some\\other\\path".to_string(),
nu_protocol::Span::new(0, dir_str.len()),
),
);
#[cfg(not(windows))]
stack.add_env_var(
"PATH".to_string(),
Value::string(
"/some/path:/some/other/path".to_string(),
nu_protocol::Span::new(0, dir_str.len()),
),
);
// Merge environment into the permanent state
let merge_result = engine_state.merge_env(&mut stack, &dir);
assert!(merge_result.is_ok());
(dir, dir_str, engine_state, stack)
}
pub fn new_quote_engine() -> (PathBuf, String, EngineState, Stack) {
// Target folder inside assets
let dir = fs::fixtures().join("quoted_completions");
let mut dir_str = dir
.clone()
.into_os_string()
.into_string()
.unwrap_or_default();
dir_str.push(SEP);
// Create a new engine with default context
let mut engine_state = create_default_context();
// New stack
let mut stack = Stack::new();
// Add pwd as env var
stack.add_env_var(
"PWD".to_string(),
Value::string(dir_str.clone(), nu_protocol::Span::new(0, dir_str.len())),
);
stack.add_env_var(
"TEST".to_string(),
Value::string(
"NUSHELL".to_string(),
nu_protocol::Span::new(0, dir_str.len()),
),
);
// Merge environment into the permanent state
let merge_result = engine_state.merge_env(&mut stack, &dir);
assert!(merge_result.is_ok());
(dir, dir_str, engine_state, stack)
}
pub fn new_partial_engine() -> (PathBuf, String, EngineState, Stack) {
// Target folder inside assets
let dir = fs::fixtures().join("partial_completions");
let mut dir_str = dir
.clone()
.into_os_string()
.into_string()
.unwrap_or_default();
dir_str.push(SEP);
// Create a new engine with default context
let mut engine_state = create_default_context();
// New stack
let mut stack = Stack::new();
// Add pwd as env var
stack.add_env_var(
"PWD".to_string(),
Value::string(dir_str.clone(), nu_protocol::Span::new(0, dir_str.len())),
);
stack.add_env_var(
"TEST".to_string(),
Value::string(
"NUSHELL".to_string(),
nu_protocol::Span::new(0, dir_str.len()),
),
);
// Merge environment into the permanent state
let merge_result = engine_state.merge_env(&mut stack, &dir);
assert!(merge_result.is_ok());
(dir, dir_str, engine_state, stack)
}
// match a list of suggestions with the expected values
pub fn match_suggestions(expected: Vec<String>, suggestions: Vec<Suggestion>) {
let expected_len = expected.len();
let suggestions_len = suggestions.len();
if expected_len != suggestions_len {
panic!(
"\nexpected {expected_len} suggestions but got {suggestions_len}: \n\
Suggestions: {suggestions:#?} \n\
Expected: {expected:#?}\n"
)
}
expected.iter().zip(suggestions).for_each(|it| {
assert_eq!(it.0, &it.1.value);
});
}
// append the separator to the converted path
pub fn folder(path: PathBuf) -> String {
let mut converted_path = file(path);
converted_path.push(SEP);
converted_path
}
// convert a given path to string
pub fn file(path: PathBuf) -> String {
path.into_os_string().into_string().unwrap_or_default()
}
// merge_input executes the given input into the engine
// and merges the state
pub fn merge_input(
input: &[u8],
engine_state: &mut EngineState,
stack: &mut Stack,
dir: PathBuf,
) -> Result<(), ShellError> {
let (block, delta) = {
let mut working_set = StateWorkingSet::new(engine_state);
let block = parse(&mut working_set, None, input, false);
assert!(working_set.parse_errors.is_empty());
(block, working_set.render())
};
engine_state.merge_delta(delta)?;
assert!(eval_block::<WithoutDebug>(
engine_state,
stack,
&block,
PipelineData::Value(Value::nothing(Span::unknown()), None),
)
.is_ok());
// Merge environment into the permanent state
engine_state.merge_env(stack, &dir)
}