Commit Graph

6 Commits

Author SHA1 Message Date
YizhePKU
6c649809d3
Rewrite run_external.rs (#12921)
This PR is a complete rewrite of `run_external.rs`. The main goal of the
rewrite is improving readability, but it also fixes some bugs related to
argument handling and the PATH variable (fixes
https://github.com/nushell/nushell/issues/6011).

I'll discuss some technical details to make reviewing easier.

## Argument handling

Quoting arguments for external commands is hard. Like, *really* hard.
We've had more than a dozen issues and PRs dedicated to quoting
arguments (see Appendix) but the current implementation is still buggy.

Here's a demonstration of the buggy behavior:

```nu
let foo = "'bar'"
^touch $foo            # This creates a file named `bar`, but it should be `'bar'`
^touch ...[ "'bar'" ]  # Same
```

I'll describe how this PR deals with argument handling.

First, we'll introduce the concept of **bare strings**. Bare strings are
**string literals** that are either **unquoted** or **quoted by
backticks** [^1]. Strings within a list literal are NOT considered bare
strings, even if they are unquoted or quoted by backticks.

When a bare string is used as an argument to external process, we need
to perform tilde-expansion, glob-expansion, and inner-quotes-removal, in
that order. "Inner-quotes-removal" means transforming from
`--option="value"` into `--option=value`.

## `.bat` files and CMD built-ins

On Windows, `.bat` files and `.cmd` files are considered executable, but
they need `CMD.exe` as the interpreter. The Rust standard library
supports running `.bat` files directly and will spawn `CMD.exe` under
the hood (see
[documentation](https://doc.rust-lang.org/std/process/index.html#windows-argument-splitting)).
However, other extensions are not supported [^2].

Nushell also supports a selected number of CMD built-ins. The problem
with CMD is that it uses a different set of quoting rules. Correctly
quoting for CMD requires using
[Command::raw_arg()](https://doc.rust-lang.org/std/os/windows/process/trait.CommandExt.html#tymethod.raw_arg)
and manually quoting CMD special characters, on top of quoting from the
Nushell side. ~~I decided that this is too complex and chose to reject
special characters in CMD built-ins instead [^3]. Hopefully this will
not affact real-world use cases.~~ I've implemented escaping that works
reasonably well.

## `which-support` feature

The `which` crate is now a hard dependency of `nu-command`, making the
`which-support` feature essentially useless. The `which` crate is
already a hard dependency of `nu-cli`, and we should consider removing
the `which-support` feature entirely.

## Appendix

Here's a list of quoting-related issues and PRs in rough chronological
order.

* https://github.com/nushell/nushell/issues/4609
* https://github.com/nushell/nushell/issues/4631
* https://github.com/nushell/nushell/issues/4601
  * https://github.com/nushell/nushell/pull/5846
* https://github.com/nushell/nushell/issues/5978
  * https://github.com/nushell/nushell/pull/6014
* https://github.com/nushell/nushell/issues/6154
  * https://github.com/nushell/nushell/pull/6161
* https://github.com/nushell/nushell/issues/6399
  * https://github.com/nushell/nushell/pull/6420
  * https://github.com/nushell/nushell/pull/6426
* https://github.com/nushell/nushell/issues/6465
* https://github.com/nushell/nushell/issues/6559
  * https://github.com/nushell/nushell/pull/6560

[^1]: The idea that backtick-quoted strings act like bare strings was
introduced by Kubouch and briefly mentioned in [the language
reference](https://www.nushell.sh/lang-guide/chapters/strings_and_text.html#backtick-quotes).

[^2]: The documentation also said "running .bat scripts in this way may
be removed in the future and so should not be relied upon", which is
another reason to move away from this. But again, quoting for CMD is
hard.

[^3]: If anyone wants to try, the best resource I found on the topic is
[this](https://daviddeley.com/autohotkey/parameters/parameters.htm).
2024-05-23 02:05:27 +00:00
Ian Manske
cab86f49c0
Fix pipe redirection into complete (#12818)
# Description
Fixes #12796 where a combined out and err pipe redirection (`o+e>|`)
into `complete` still provides separate `stdout` and `stderr` columns in
the record. Now, the combined output will be in the `stdout` column.
This PR also fixes a similar error with the `e>|` pipe redirection.

# Tests + Formatting
Added two tests.
2024-05-11 15:32:00 +00:00
Stefan Holderbach
406df7f208
Avoid taking unnecessary ownership of intermediates (#12740)
# Description

Judiciously try to avoid allocations/clone by changing the signature of
functions

- **Don't pass str by value unnecessarily if only read**
- **Don't require a vec in `Sandbox::with_files`**
- **Remove unnecessary string clone**
- **Fixup unnecessary borrow**
- **Use `&str` in shape color instead**
- **Vec -> Slice**
- **Elide string clone**
- **Elide `Path` clone**
- **Take &str to elide clone in tests**

# User-Facing Changes
None

# Tests + Formatting
This touches many tests purely in changing from owned to borrowed/static
data
2024-05-04 00:53:15 +00:00
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
tomoda
77f10eb270
Fix the test which fails on windows (#11478)
- related PR: #11463

# Description

Currently, `commands::complete::basic` fails on Windows without git
bash.
This pr fixes it.

# User-Facing Changes

(none)

# Tests + Formatting

- [x] (on Windows) `cargo fmt --all -- --check` to check standard code
formatting (`cargo fmt --all` applies these changes)
- [x] (on Windows) `cargo clippy --workspace -- -D warnings -D
clippy::unwrap_used` to check that you're using the standard code style
- [x] (on Windows without git bash, Windows with git bash and Ubuntu)
`cargo test --workspace` to check that all tests pass (on Windows make
sure to [enable developer
mode](https://learn.microsoft.com/en-us/windows/apps/get-started/developer-mode-features-and-debugging))
- on my Windows with Japanese lang pack: 1 test still fails. (see
#11463)
- [x] (on Windows and Ubuntu) `cargo run -- -c "use std testing; testing
run-tests --path crates/nu-std"` to run the tests for the standard
library

# After Submitting

(none)
2024-01-03 07:22:43 -06:00
Andrej Kolchin
020e121391
Bubble up errors passed to complete (#11313)
Errors passed in `PipelineData::Value` get thrown in `complete` now.

Also added two simple tests for the command.

Fix #11187
Fix #10204
2023-12-16 09:07:08 -06:00