# Description
Title says it all, changes `EngineState::get_env_var` to return a
`Option<&'a Value>` instead of an owned `Option<Value>`. This avoids
some unnecessary clones.
I also made a similar change to the `PluginExecutionContext` trait.
This PR sets the current working directory to the location of the
Nushell executable at startup, using `std::env::set_current_dir()`. This
is desirable because after PR
https://github.com/nushell/nushell/pull/12922, we no longer change our
current working directory even after `cd` is executed, and some OS might
lock the directory where Nushell started.
The location of the Nushell executable is chosen because it cannot be
removed while Nushell is running anyways, so we don't have to worry
about OS locking it.
This PR has the side effect that it breaks buggy command even harder.
I'll keep this PR as a draft until these commands are fixed, but it
might be helpful to pull this PR if you're working on fixing one of
those bugs.
---------
Co-authored-by: Devyn Cairns <devyn.cairns@gmail.com>
Co-authored-by: Darren Schroeder <343840+fdncred@users.noreply.github.com>
# Description
This PR makes it so that non-zero exit codes and termination by signal
are treated as a normal `ShellError`. Currently, these are silent
errors. That is, if an external command fails, then it's code block is
aborted, but the parent block can sometimes continue execution. E.g.,
see #8569 and this example:
```nushell
[1 2] | each { ^false }
```
Before this would give:
```
╭───┬──╮
│ 0 │ │
│ 1 │ │
╰───┴──╯
```
Now, this shows an error:
```
Error: nu:🐚:eval_block_with_input
× Eval block failed with pipeline input
╭─[entry #1:1:2]
1 │ [1 2] | each { ^false }
· ┬
· ╰── source value
╰────
Error: nu:🐚:non_zero_exit_code
× External command had a non-zero exit code
╭─[entry #1:1:17]
1 │ [1 2] | each { ^false }
· ──┬──
· ╰── exited with code 1
╰────
```
This PR fixes#12874, fixes#5960, fixes#10856, and fixes#5347. This
PR also partially addresses #10633 and #10624 (only the last command of
a pipeline is currently checked). It looks like #8569 is already fixed,
but this PR will make sure it is definitely fixed (fixes#8569).
# User-Facing Changes
- Non-zero exit codes and termination by signal now cause an error to be
thrown.
- The error record value passed to a `catch` block may now have an
`exit_code` column containing the integer exit code if the error was due
to an external command.
- Adds new config values, `display_errors.exit_code` and
`display_errors.termination_signal`, which determine whether an error
message should be printed in the respective error cases. For
non-interactive sessions, these are set to `true`, and for interactive
sessions `display_errors.exit_code` is false (via the default config).
# Tests
Added a few tests.
# After Submitting
- Update docs and book.
- Future work:
- Error if other external commands besides the last in a pipeline exit
with a non-zero exit code. Then, deprecate `do -c` since this will be
the default behavior everywhere.
- Add a better mechanism for exit codes and deprecate
`$env.LAST_EXIT_CODE` (it's buggy).
# Description
After discussing with @sholderbach the cumbersome usage of
`nu_protocol::Value` in Rust, I created a derive macro to simplify it.
I’ve added a new crate called `nu-derive-value`, which includes two
macros, `IntoValue` and `FromValue`. These are re-exported in
`nu-protocol` and should be encouraged to be used via that re-export.
The macros ensure that all types can easily convert from and into
`Value`. For example, as a plugin author, you can define your plugin
configuration using a Rust struct and easily convert it using
`FromValue`. This makes plugin configuration less of a hassle.
I introduced the `IntoValue` trait for a standardized approach to
converting values into `Value` (and a fallible variant `TryIntoValue`).
This trait could potentially replace existing `into_value` methods.
Along with this, I've implemented `FromValue` for several standard types
and refined other implementations to use blanket implementations where
applicable.
I made these design choices with input from @devyn.
There are more improvements possible, but this is a solid start and the
PR is already quite substantial.
# User-Facing Changes
For `nu-protocol` users, these changes simplify the handling of
`Value`s. There are no changes for end-users of nushell itself.
# Tests + Formatting
Documenting the macros itself is not really possible, as they cannot
really reference any other types since they are the root of the
dependency graph. The standard library has the same problem
([std::Debug](https://doc.rust-lang.org/stable/std/fmt/derive.Debug.html)).
However I documented the `FromValue` and `IntoValue` traits completely.
For testing, I made of use `proc-macro2` in the derive macro code. This
would allow testing the generated source code. Instead I just tested
that the derived functionality is correct. This is done in
`nu_protocol::value::test_derive`, as a consumer of `nu-derive-value`
needs to do the testing of the macro usage. I think that these tests
should provide a stable baseline so that users can be sure that the impl
works.
# After Submitting
With these macros available, we can probably use them in some examples
for plugins to showcase the use of them.
As discussed in https://github.com/nushell/nushell/pull/12749, we no
longer need to call `std::env::set_current_dir()` to sync `$env.PWD`
with the actual working directory. This PR removes the call from
`EngineState::merge_env()`.
# Description
`Value` describes the types of first-class values that users and scripts
can create, manipulate, pass around, and store. However, `Block`s are
not first-class values in the language, so this PR removes it from
`Value`. This removes some unnecessary code, and this change should be
invisible to the user except for the change to `scope modules` described
below.
# User-Facing Changes
Breaking change: the output of `scope modules` was changed so that
`env_block` is now `has_env_block` which is a boolean value instead of a
`Block`.
# After Submitting
Update the language guide possibly.
# 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.
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# Description
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Boxes `Record` inside `Value` to reduce memory usage, `Value` goes from
`72` -> `56` bytes after this change.
# User-Facing Changes
<!-- List of all changes that impact the user experience here. This
helps us keep track of breaking changes. -->
# Tests + Formatting
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# After Submitting
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# Description
This makes many of the larger objects in `EngineState` into `Arc`, and
uses `Arc::make_mut` to do clone-on-write if the reference is not
unique. This is generally very cheap, giving us the best of both worlds
- allowing us to mutate without cloning if we have an exclusive
reference, and cloning if we don't.
This started as more of a curiosity for me after remembering that
`Arc::make_mut` exists and can make using `Arc` for mostly immutable
data that sometimes needs to be changed very convenient, and also after
hearing someone complain about memory usage on Discord - this is a
somewhat significant win for that.
The exact objects that were wrapped in `Arc`:
- `files`, `file_contents` - the strings and byte buffers
- `decls` - the whole `Vec`, but mostly to avoid lots of individual
`malloc()` calls on Clone rather than for memory usage
- `blocks` - the blocks themselves, rather than the outer Vec
- `modules` - the modules themselves, rather than the outer Vec
- `env_vars`, `previous_env_vars` - the entire maps
- `config`
The changes required were relatively minimal, but this is a breaking API
change. In particular, blocks are added as Arcs, to allow the parser
cache functionality to work.
With my normal nu config, running on Linux, this saves me about 15 MiB
of process memory usage when running interactively (65 MiB → 50 MiB).
This also makes quick command executions cheaper, particularly since
every REPL loop now involves a clone of the engine state so that we can
recover from a panic. It also reduces memory usage where engine state
needs to be cloned and sent to another thread or kept within an
iterator.
# User-Facing Changes
Shouldn't be any, since it's all internal stuff, but it does change some
public interfaces so it's a breaking change
# 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.
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# Description
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This PR adds a new evaluator path with callbacks to a mutable trait
object implementing a Debugger trait. The trait object can do anything,
e.g., profiling, code coverage, step debugging. Currently,
entering/leaving a block and a pipeline element is marked with
callbacks, but more callbacks can be added as necessary. Not all
callbacks need to be used by all debuggers; unused ones are simply empty
calls. A simple profiler is implemented as a proof of concept.
The debugging support is implementing by making `eval_xxx()` functions
generic depending on whether we're debugging or not. This has zero
computational overhead, but makes the binary slightly larger (see
benchmarks below). `eval_xxx()` variants called from commands (like
`eval_block_with_early_return()` in `each`) are chosen with a dynamic
dispatch for two reasons: to not grow the binary size due to duplicating
the code of many commands, and for the fact that it isn't possible
because it would make Command trait objects object-unsafe.
In the future, I hope it will be possible to allow plugin callbacks such
that users would be able to implement their profiler plugins instead of
having to recompile Nushell.
[DAP](https://microsoft.github.io/debug-adapter-protocol/) would also be
interesting to explore.
Try `help debug profile`.
## Screenshots
Basic output:

To profile with more granularity, increase the profiler depth (you'll
see that repeated `is-windows` calls take a large chunk of total time,
making it a good candidate for optimizing):

## Benchmarks
### Binary size
Binary size increase vs. main: **+40360 bytes**. _(Both built with
`--release --features=extra,dataframe`.)_
### Time
```nushell
# bench_debug.nu
use std bench
let test = {
1..100
| each {
ls | each {|row| $row.name | str length }
}
| flatten
| math avg
}
print 'debug:'
let res2 = bench { debug profile $test } --pretty
print $res2
```
```nushell
# bench_nodebug.nu
use std bench
let test = {
1..100
| each {
ls | each {|row| $row.name | str length }
}
| flatten
| math avg
}
print 'no debug:'
let res1 = bench { do $test } --pretty
print $res1
```
`cargo run --release -- bench_debug.nu` is consistently 1--2 ms slower
than `cargo run --release -- bench_nodebug.nu` due to the collection
overhead + gathering the report. This is expected. When gathering more
stuff, the overhead is obviously higher.
`cargo run --release -- bench_nodebug.nu` vs. `nu bench_nodebug.nu` I
didn't measure any difference. Both benchmarks report times between 97
and 103 ms randomly, without one being consistently higher than the
other. This suggests that at least in this particular case, when not
running any debugger, there is no runtime overhead.
## API changes
This PR adds a generic parameter to all `eval_xxx` functions that forces
you to specify whether you use the debugger. You can resolve it in two
ways:
* Use a provided helper that will figure it out for you. If you wanted
to use `eval_block(&engine_state, ...)`, call `let eval_block =
get_eval_block(&engine_state); eval_block(&engine_state, ...)`
* If you know you're in an evaluation path that doesn't need debugger
support, call `eval_block::<WithoutDebug>(&engine_state, ...)` (this is
the case of hooks, for example).
I tried to add more explanation in the docstring of `debugger_trait.rs`.
## TODO
- [x] Better profiler output to reduce spam of iterative commands like
`each`
- [x] Resolve `TODO: DEBUG` comments
- [x] Resolve unwraps
- [x] Add doc comments
- [x] Add usage and extra usage for `debug profile`, explaining all
columns
# User-Facing Changes
<!-- List of all changes that impact the user experience here. This
helps us keep track of breaking changes. -->
Hopefully none.
# Tests + Formatting
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> ```
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# After Submitting
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# Description
This PR renames the conversion functions on `Value` to be more consistent.
It follows the Rust [API guidelines](https://rust-lang.github.io/api-guidelines/naming.html#ad-hoc-conversions-follow-as_-to_-into_-conventions-c-conv) for ad-hoc conversions.
The conversion functions on `Value` now come in a few forms:
- `coerce_{type}` takes a `&Value` and attempts to convert the value to
`type` (e.g., `i64` are converted to `f64`). This is the old behavior of
some of the `as_{type}` functions -- these functions have simply been
renamed to better reflect what they do.
- The new `as_{type}` functions take a `&Value` and returns an `Ok`
result only if the value is of `type` (no conversion is attempted). The
returned value will be borrowed if `type` is non-`Copy`, otherwise an
owned value is returned.
- `into_{type}` exists for non-`Copy` types, but otherwise does not
attempt conversion just like `as_type`. It takes an owned `Value` and
always returns an owned result.
- `coerce_into_{type}` has the same relationship with `coerce_{type}` as
`into_{type}` does with `as_{type}`.
- `to_{kind}_string`: conversion to different string formats (debug,
abbreviated, etc.). Only two of the old string conversion functions were
removed, the rest have been renamed only.
- `to_{type}`: other conversion functions. Currently, only `to_path`
exists. (And `to_string` through `Display`.)
This table summaries the above:
| Form | Cost | Input Ownership | Output Ownership | Converts `Value`
case/`type` |
| ---------------------------- | ----- | --------------- |
---------------- | -------- |
| `as_{type}` | Cheap | Borrowed | Borrowed/Owned | No |
| `into_{type}` | Cheap | Owned | Owned | No |
| `coerce_{type}` | Cheap | Borrowed | Borrowed/Owned | Yes |
| `coerce_into_{type}` | Cheap | Owned | Owned | Yes |
| `to_{kind}_string` | Expensive | Borrowed | Owned | Yes |
| `to_{type}` | Expensive | Borrowed | Owned | Yes |
# User-Facing Changes
Breaking API change for `Value` in `nu-protocol` which is exposed as
part of the plugin API.
# Description
Where appropriate, this PR replaces instances of
`Value::get_data_by_key` and `Value::follow_cell_path` with
`Record::get`. This avoids some unnecessary clones and simplifies the
code in some places.
# Description
Reuses the existing `Closure` type in `Value::Closure`. This will help
with the span refactoring for `Value`. Additionally, this allows us to
more easily box or unbox the `Closure` case should we chose to do so in
the future.
# User-Facing Changes
Breaking API change for `nu_protocol`.
# Description
As part of the refactor to split spans off of Value, this moves to using
helper functions to create values, and using `.span()` instead of
matching span out of Value directly.
Hoping to get a few more helping hands to finish this, as there are a
lot of commands to update :)
# User-Facing Changes
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helps us keep track of breaking changes. -->
# Tests + Formatting
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automatically
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> ```
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# After Submitting
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---------
Co-authored-by: Darren Schroeder <343840+fdncred@users.noreply.github.com>
Co-authored-by: WindSoilder <windsoilder@outlook.com>
I moved hook to *nu_cmd_base* instead of *nu_cli* because it will enable
other developers to continue to use hook even if they decide to write
their on cli or NOT depend on nu-cli
Then they will still have the hook functionality because they can
include nu-cmd-base