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Author SHA1 Message Date
Piepmatz
66bc0542e0
Refactor I/O Errors (#14927)
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# Description
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As mentioned in #10698, we have too many `ShellError` variants, with
some even overlapping in meaning. This PR simplifies and improves I/O
error handling by restructuring `ShellError` related to I/O issues.
Previously, `ShellError::IOError` only contained a message string,
making it convenient but overly generic. It was widely used without
providing spans (#4323).

This PR introduces a new `ShellError::Io` variant that consolidates
multiple I/O-related errors (except for `ShellError::NetworkFailure`,
which remains distinct for now). The new `ShellError::Io` variant
replaces the following:

- `FileNotFound`
- `FileNotFoundCustom`
- `IOInterrupted`
- `IOError`
- `IOErrorSpanned`
- `NotADirectory`
- `DirectoryNotFound`
- `MoveNotPossible`
- `CreateNotPossible`
- `ChangeAccessTimeNotPossible`
- `ChangeModifiedTimeNotPossible`
- `RemoveNotPossible`
- `ReadingFile`

## The `IoError`
`IoError` includes the following fields:

1. **`kind`**: Extends `std::io::ErrorKind` to specify the type of I/O
error without needing new `ShellError` variants. This aligns with the
approach used in `std::io::Error`. This adds a second dimension to error
reporting by combining the `kind` field with `ShellError` variants,
making it easier to describe errors in more detail. As proposed by
@kubouch in [#design-discussion on
Discord](https://discord.com/channels/601130461678272522/615329862395101194/1323699197165178930),
this helps reduce the number of `ShellError` variants. In the error
report, the `kind` field is displayed as the "source" of the error,
e.g., "I/O error," followed by the specific kind of I/O error.
2. **`span`**: A non-optional field to encourage providing spans for
better error reporting (#4323).
3. **`path`**: Optional `PathBuf` to give context about the file or
directory involved in the error (#7695). If provided, it’s shown as a
help entry in error reports.
4. **`additional_context`**: Allows adding custom messages when the
span, kind, and path are insufficient. This is rendered in the error
report at the labeled span.
5. **`location`**: Sometimes, I/O errors occur in the engine itself and
are not caused directly by user input. In such cases, if we don’t have a
span and must set it to `Span::unknown()`, we need another way to
reference the error. For this, the `location` field uses the new
`Location` struct, which records the Rust file and line number where the
error occurred. This ensures that we at least know the Rust code
location that failed, helping with debugging. To make this work, a new
`location!` macro was added, which retrieves `file!`, `line!`, and
`column!` values accurately. If `Location::new` is used directly, it
issues a warning to remind developers to use the macro instead, ensuring
consistent and correct usage.

### Constructor Behavior
`IoError` provides five constructor methods:
- `new` and `new_with_additional_context`: Used for errors caused by
user input and require a valid (non-unknown) span to ensure precise
error reporting.
- `new_internal` and `new_internal_with_path`: Used for internal errors
where a span is not available. These methods require additional context
and the `Location` struct to pinpoint the source of the error in the
engine code.
- `factory`: Returns a closure that maps an `std::io::Error` to an
`IoError`. This is useful for handling multiple I/O errors that share
the same span and path, streamlining error handling in such cases.

## New Report Look
This is simulation how the I/O errors look like (the `open crates` is
simulated to show how internal errors are referenced now):
![Screenshot 2025-01-25
190426](https://github.com/user-attachments/assets/a41b6aa6-a440-497d-bbcc-3ac0121c9226)

## `Span::test_data()`
To enable better testing, `Span::test_data()` now returns a value
distinct from `Span::unknown()`. Both `Span::test_data()` and
`Span::unknown()` refer to invalid source code, but having a separate
value for test data helps identify issues during testing while keeping
spans unique.

## Cursed Sneaky Error Transfers
I removed the conversions between `std::io::Error` and `ShellError` as
they often removed important information and were used too broadly to
handle I/O errors. This also removed the problematic implementation
found here:

7ea4895513/crates/nu-protocol/src/errors/shell_error.rs (L1534-L1583)

which hid some downcasting from I/O errors and made it hard to trace
where `ShellError` was converted into `std::io::Error`. To address this,
I introduced a new struct called `ShellErrorBridge`, which explicitly
defines this transfer behavior. With `ShellErrorBridge`, we can now
easily grep the codebase to locate and manage such conversions.

## Miscellaneous
- Removed the OS error added in #14640, as it’s no longer needed.
- Improved error messages in `glob_from` (#14679).
- Trying to open a directory with `open` caused a permissions denied
error (it's just what the OS provides). I added a `is_dir` check to
provide a better error in that case.

# User-Facing Changes
<!-- List of all changes that impact the user experience here. This
helps us keep track of breaking changes. -->

- Error outputs now include more detailed information and are formatted
differently, including updated error codes.
- The structure of `ShellError` has changed, requiring plugin authors
and embedders to update their implementations.

# Tests + Formatting
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> from `nushell` you can also use the `toolkit` as follows
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> use toolkit.nu # or use an `env_change` hook to activate it
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> toolkit check pr
> ```
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I updated tests to account for the new I/O error structure and
formatting changes.

# After Submitting
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This PR closes #7695 and closes #14892 and partially addresses #4323 and
#10698.

---------

Co-authored-by: Darren Schroeder <343840+fdncred@users.noreply.github.com>
2025-01-28 16:03:31 -06:00
Ian Manske
c560bac13f
Add --long flag for sys cpu (#14485)
# Description

Fixes #14470 where the `sys cpu` command is slow. This was done by
removing the `cpu_usage` column from the default output, since it takes
400ms to calculate. Instead a `--long` flag was added that, when
provided, adds back the `cpu_usage` column.

```nu
# Before
> bench { sys cpu | length } | get mean
401ms 591µs 896ns

# After
> bench { sys cpu | length } | get mean
500µs 13ns # around 1-2ms in practice
```

# User-Facing Changes

- `sys cpu` no longer has a `cpu_usage` column by default.
- Added  a `--long` flag for `sys cpu` to add back the removed column.
2024-12-01 05:56:42 -06:00
Devyn Cairns
d7392f1f3b
Internal representation (IR) compiler and evaluator (#13330)
# Description

This PR adds an internal representation language to Nushell, offering an
alternative evaluator based on simple instructions, stream-containing
registers, and indexed control flow. The number of registers required is
determined statically at compile-time, and the fixed size required is
allocated upon entering the block.

Each instruction is associated with a span, which makes going backwards
from IR instructions to source code very easy.

Motivations for IR:

1. **Performance.** By simplifying the evaluation path and making it
more cache-friendly and branch predictor-friendly, code that does a lot
of computation in Nushell itself can be sped up a decent bit. Because
the IR is fairly easy to reason about, we can also implement
optimization passes in the future to eliminate and simplify code.
2. **Correctness.** The instructions mostly have very simple and
easily-specified behavior, so hopefully engine changes are a little bit
easier to reason about, and they can be specified in a more formal way
at some point. I have made an effort to document each of the
instructions in the docs for the enum itself in a reasonably specific
way. Some of the errors that would have happened during evaluation
before are now moved to the compilation step instead, because they don't
make sense to check during evaluation.
3. **As an intermediate target.** This is a good step for us to bring
the [`new-nu-parser`](https://github.com/nushell/new-nu-parser) in at
some point, as code generated from new AST can be directly compared to
code generated from old AST. If the IR code is functionally equivalent,
it will behave the exact same way.
4. **Debugging.** With a little bit more work, we can probably give
control over advancing the virtual machine that `IrBlock`s run on to
some sort of external driver, making things like breakpoints and single
stepping possible. Tools like `view ir` and [`explore
ir`](https://github.com/devyn/nu_plugin_explore_ir) make it easier than
before to see what exactly is going on with your Nushell code.

The goal is to eventually replace the AST evaluator entirely, once we're
sure it's working just as well. You can help dogfood this by running
Nushell with `$env.NU_USE_IR` set to some value. The environment
variable is checked when Nushell starts, so config runs with IR, or it
can also be set on a line at the REPL to change it dynamically. It is
also checked when running `do` in case within a script you want to just
run a specific piece of code with or without IR.

# Example

```nushell
view ir { |data|
  mut sum = 0
  for n in $data {
    $sum += $n
  }
  $sum
}
```
  
```gas
# 3 registers, 19 instructions, 0 bytes of data
   0: load-literal           %0, int(0)
   1: store-variable         var 904, %0 # let
   2: drain                  %0
   3: drop                   %0
   4: load-variable          %1, var 903
   5: iterate                %0, %1, end 15 # for, label(1), from(14:)
   6: store-variable         var 905, %0
   7: load-variable          %0, var 904
   8: load-variable          %2, var 905
   9: binary-op              %0, Math(Plus), %2
  10: span                   %0
  11: store-variable         var 904, %0
  12: load-literal           %0, nothing
  13: drain                  %0
  14: jump                   5
  15: drop                   %0          # label(0), from(5:)
  16: drain                  %0
  17: load-variable          %0, var 904
  18: return                 %0
```

# Benchmarks

All benchmarks run on a base model Mac Mini M1.

## Iterative Fibonacci sequence

This is about as best case as possible, making use of the much faster
control flow. Most code will not experience a speed improvement nearly
this large.

```nushell
def fib [n: int] {
  mut a = 0
  mut b = 1
  for _ in 2..=$n {
    let c = $a + $b
    $a = $b
    $b = $c
  }
  $b
}
use std bench
bench { 0..50 | each { |n| fib $n } }
```

IR disabled:

```
╭───────┬─────────────────╮
│ mean  │ 1ms 924µs 665ns │
│ min   │ 1ms 700µs 83ns  │
│ max   │ 3ms 450µs 125ns │
│ std   │ 395µs 759ns     │
│ times │ [list 50 items] │
╰───────┴─────────────────╯
```

IR enabled:

```
╭───────┬─────────────────╮
│ mean  │ 452µs 820ns     │
│ min   │ 427µs 417ns     │
│ max   │ 540µs 167ns     │
│ std   │ 17µs 158ns      │
│ times │ [list 50 items] │
╰───────┴─────────────────╯
```

![explore ir
view](https://github.com/nushell/nushell/assets/10729/d7bccc03-5222-461c-9200-0dce71b83b83)

##
[gradient_benchmark_no_check.nu](https://github.com/nushell/nu_scripts/blob/main/benchmarks/gradient_benchmark_no_check.nu)

IR disabled:

```
╭───┬──────────────────╮
│ 0 │ 27ms 929µs 958ns │
│ 1 │ 21ms 153µs 459ns │
│ 2 │ 18ms 639µs 666ns │
│ 3 │ 19ms 554µs 583ns │
│ 4 │ 13ms 383µs 375ns │
│ 5 │ 11ms 328µs 208ns │
│ 6 │  5ms 659µs 542ns │
╰───┴──────────────────╯
```

IR enabled:

```
╭───┬──────────────────╮
│ 0 │       22ms 662µs │
│ 1 │ 17ms 221µs 792ns │
│ 2 │ 14ms 786µs 708ns │
│ 3 │ 13ms 876µs 834ns │
│ 4 │  13ms 52µs 875ns │
│ 5 │ 11ms 269µs 666ns │
│ 6 │  6ms 942µs 500ns │
╰───┴──────────────────╯
```

##
[random-bytes.nu](https://github.com/nushell/nu_scripts/blob/main/benchmarks/random-bytes.nu)

I got pretty random results out of this benchmark so I decided not to
include it. Not clear why.

# User-Facing Changes
- IR compilation errors may appear even if the user isn't evaluating
with IR.
- IR evaluation can be enabled by setting the `NU_USE_IR` environment
variable to any value.
- New command `view ir` pretty-prints the IR for a block, and `view ir
--json` can be piped into an external tool like [`explore
ir`](https://github.com/devyn/nu_plugin_explore_ir).

# Tests + Formatting
All tests are passing with `NU_USE_IR=1`, and I've added some more eval
tests to compare the results for some very core operations. I will
probably want to add some more so we don't have to always check
`NU_USE_IR=1 toolkit test --workspace` on a regular basis.

# After Submitting
- [ ] release notes
- [ ] further documentation of instructions?
- [ ] post-release: publish `nu_plugin_explore_ir`
2024-07-10 17:33:59 -07:00
Embers-of-the-Fire
96493b26d9
Make string related commands parse-time evaluatable (#13032)
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Related meta-issue: #10239.

# Description
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This PR will modify some `str`-related commands so that they can be
evaluated at parse time.

See the following list for those implemented by this pr.

# User-Facing Changes
<!-- List of all changes that impact the user experience here. This
helps us keep track of breaking changes. -->

Available now:
- `str` subcommands
  - `trim`
  - `contains`
  - `distance`
  - `ends-with`
  - `expand`
  - `index-of`
  - `join`
  - `replace`
  - `reverse`
  - `starts-with`
  - `stats`
  - `substring`
  - `capitalize`
  - `downcase`
  - `upcase`
- `split` subcommands
  - `chars`
  - `column`
  - `list`
  - `row`
  - `words`
- `format` subcommands
  - `date`
  - `duration`
  - `filesize`
- string related commands
  - `parse`
  - `detect columns`
  - `encode` & `decode`

# Tests + Formatting
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Make sure you've run and fixed any issues with these commands:

- `cargo fmt --all -- --check` to check standard code formatting (`cargo
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- `cargo run -- -c "use toolkit.nu; toolkit test stdlib"` to run the
tests for the standard library

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> ```
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Unresolved questions:
- [ ] Is there any routine of testing const expressions? I haven't found
any yet.
- [ ] Is const expressions required to behave just like there non-const
version, like what rust promises?

# 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.
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Unresolved questions:
- [ ] Do const commands need special marks in the docs?
2024-06-05 22:21:52 +03:00
Devyn Cairns
c61075e20e
Add string/binary type color to ByteStream (#12897)
# Description

This PR allows byte streams to optionally be colored as being
specifically binary or string data, which guarantees that they'll be
converted to `Binary` or `String` appropriately on `into_value()`,
making them compatible with `Type` guarantees. This makes them
significantly more broadly usable for command input and output.

There is still an `Unknown` type for byte streams coming from external
commands, which uses the same behavior as we previously did where it's a
string if it's UTF-8.

A small number of commands were updated to take advantage of this, just
to prove the point. I will be adding more after this merges.

# User-Facing Changes
- New types in `describe`: `string (stream)`, `binary (stream)`
- These commands now return a stream if their input was a stream:
  - `into binary`
  - `into string`
  - `bytes collect`
  - `str join`
  - `first` (binary)
  - `last` (binary)
  - `take` (binary)
  - `skip` (binary)
- Streams that are explicitly binary colored will print as a streaming
hexdump
  - example:
    ```nushell
    1.. | each { into binary } | bytes collect
    ```

# Tests + Formatting
I've added some tests to cover it at a basic level, and it doesn't break
anything existing, but I do think more would be nice. Some of those will
come when I modify more commands to stream.

# After Submitting
There are a few things I'm not quite satisfied with:

- **String trimming behavior.** We automatically trim newlines from
streams from external commands, but I don't think we should do this with
internal commands. If I call a command that happens to turn my string
into a stream, I don't want the newline to suddenly disappear. I changed
this to specifically do it only on `Child` and `File`, but I don't know
if this is quite right, and maybe we should bring back the old flag for
`trim_end_newline`
- **Known binary always resulting in a hexdump.** It would be nice to
have a `print --raw`, so that we can put binary data on stdout
explicitly if we want to. This PR doesn't change how external commands
work though - they still dump straight to stdout.

Otherwise, here's the normal checklist:

- [ ] release notes
- [ ] docs update for plugin protocol changes (added `type` field)

---------

Co-authored-by: Ian Manske <ian.manske@pm.me>
2024-05-20 00:35:32 +00:00
Devyn Cairns
5c7f7883c8
Add ErrSpan extension trait for Result (#12626)
# Description
This adds an extension trait to `Result` that wraps errors in `Spanned`,
saving the effort of calling `.map_err(|err| err.into_spanned(span))`
every time. This will hopefully make it even more likely that someone
will want to use a spanned `io::Error` and make it easier to remove the
impl for `From<io::Error> for ShellError` because that doesn't have span
information.
2024-04-23 10:39:55 +02:00
Ian Manske
c747ec75c9
Add command_prelude module (#12291)
# Description
When implementing a `Command`, one must also import all the types
present in the function signatures for `Command`. This makes it so that
we often import the same set of types in each command implementation
file. E.g., something like this:
```rust
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
    record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, PipelineData,
    ShellError, Signature, Span, Type, Value,
};
```

This PR adds the `nu_engine::command_prelude` module which contains the
necessary and commonly used types to implement a `Command`:
```rust
// command_prelude.rs
pub use crate::CallExt;
pub use nu_protocol::{
    ast::{Call, CellPath},
    engine::{Command, EngineState, Stack},
    record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, IntoSpanned,
    PipelineData, Record, ShellError, Signature, Span, Spanned, SyntaxShape, Type, Value,
};
```

This should reduce the boilerplate needed to implement a command and
also gives us a place to track the breadth of the `Command` API. I tried
to be conservative with what went into the prelude modules, since it
might be hard/annoying to remove items from the prelude in the future.
Let me know if something should be included or excluded.
2024-03-26 21:17:30 +00:00