Replace ExternalStream with new ByteStream type (#12774)

# Description
This PR introduces a `ByteStream` type which is a `Read`-able stream of
bytes. Internally, it has an enum over three different byte stream
sources:
```rust
pub enum ByteStreamSource {
    Read(Box<dyn Read + Send + 'static>),
    File(File),
    Child(ChildProcess),
}
```

This is in comparison to the current `RawStream` type, which is an
`Iterator<Item = Vec<u8>>` and has to allocate for each read chunk.

Currently, `PipelineData::ExternalStream` serves a weird dual role where
it is either external command output or a wrapper around `RawStream`.
`ByteStream` makes this distinction more clear (via `ByteStreamSource`)
and replaces `PipelineData::ExternalStream` in this PR:
```rust
pub enum PipelineData {
    Empty,
    Value(Value, Option<PipelineMetadata>),
    ListStream(ListStream, Option<PipelineMetadata>),
    ByteStream(ByteStream, Option<PipelineMetadata>),
}
```

The PR is relatively large, but a decent amount of it is just repetitive
changes.

This PR fixes #7017, fixes #10763, and fixes #12369.

This PR also improves performance when piping external commands. Nushell
should, in most cases, have competitive pipeline throughput compared to,
e.g., bash.
| Command | Before (MB/s) | After (MB/s) | Bash (MB/s) |
| -------------------------------------------------- | -------------:|
------------:| -----------:|
| `throughput \| rg 'x'` | 3059 | 3744 | 3739 |
| `throughput \| nu --testbin relay o> /dev/null` | 3508 | 8087 | 8136 |

# User-Facing Changes
- This is a breaking change for the plugin communication protocol,
because the `ExternalStreamInfo` was replaced with `ByteStreamInfo`.
Plugins now only have to deal with a single input stream, as opposed to
the previous three streams: stdout, stderr, and exit code.
- The output of `describe` has been changed for external/byte streams.
- Temporary breaking change: `bytes starts-with` no longer works with
byte streams. This is to keep the PR smaller, and `bytes ends-with`
already does not work on byte streams.
- If a process core dumped, then instead of having a `Value::Error` in
the `exit_code` column of the output returned from `complete`, it now is
a `Value::Int` with the negation of the signal number.

# After Submitting
- Update docs and book as necessary
- Release notes (e.g., plugin protocol changes)
- Adapt/convert commands to work with byte streams (high priority is
`str length`, `bytes starts-with`, and maybe `bytes ends-with`).
- Refactor the `tee` code, Devyn has already done some work on this.

---------

Co-authored-by: Devyn Cairns <devyn.cairns@gmail.com>

crates/nu-cmd-dataframe/src/dataframe/eager/cast.rs

@@ -79,7 +79,7 @@ impl Command for CastDF {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let value = input.into_value(call.head);
+        let value = input.into_value(call.head)?;
         if NuLazyFrame::can_downcast(&value) {
             let (dtype, column_nm) = df_args(engine_state, stack, call)?;
             let df = NuLazyFrame::try_from_value(value)?;

crates/nu-cmd-dataframe/src/dataframe/eager/filter_with.rs

@@ -72,8 +72,7 @@ impl Command for FilterWith {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let value = input.into_value(call.head);
-
+        let value = input.into_value(call.head)?;
         if NuLazyFrame::can_downcast(&value) {
             let df = NuLazyFrame::try_from_value(value)?;
             command_lazy(engine_state, stack, call, df)

crates/nu-cmd-dataframe/src/dataframe/eager/first.rs

@@ -86,7 +86,7 @@ impl Command for FirstDF {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let value = input.into_value(call.head);
+        let value = input.into_value(call.head)?;
         if NuDataFrame::can_downcast(&value) {
             let df = NuDataFrame::try_from_value(value)?;
             command(engine_state, stack, call, df)

crates/nu-cmd-dataframe/src/dataframe/eager/last.rs

@@ -61,7 +61,7 @@ impl Command for LastDF {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let value = input.into_value(call.head);
+        let value = input.into_value(call.head)?;
         if NuDataFrame::can_downcast(&value) {
             let df = NuDataFrame::try_from_value(value)?;
             command(engine_state, stack, call, df)

crates/nu-cmd-dataframe/src/dataframe/eager/rename.rs

@@ -109,8 +109,7 @@ impl Command for RenameDF {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let value = input.into_value(call.head);
-
+        let value = input.into_value(call.head)?;
         if NuLazyFrame::can_downcast(&value) {
             let df = NuLazyFrame::try_from_value(value)?;
             command_lazy(engine_state, stack, call, df)

crates/nu-cmd-dataframe/src/dataframe/eager/to_nu.rs

@@ -76,7 +76,7 @@ impl Command for ToNu {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let value = input.into_value(call.head);
+        let value = input.into_value(call.head)?;
         if NuDataFrame::can_downcast(&value) {
             dataframe_command(engine_state, stack, call, value)
         } else {

crates/nu-cmd-dataframe/src/dataframe/eager/with_column.rs

@@ -102,8 +102,7 @@ impl Command for WithColumn {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let value = input.into_value(call.head);
-
+        let value = input.into_value(call.head)?;
         if NuLazyFrame::can_downcast(&value) {
             let df = NuLazyFrame::try_from_value(value)?;
             command_lazy(engine_state, stack, call, df)

crates/nu-cmd-dataframe/src/dataframe/expressions/expressions_macro.rs

@@ -172,7 +172,7 @@ macro_rules! lazy_expr_command {
                 call: &Call,
                 input: PipelineData,
             ) -> Result<PipelineData, ShellError> {
-                let value = input.into_value(call.head);
+                let value = input.into_value(call.head)?;
                 if NuDataFrame::can_downcast(&value) {
                     let lazy = NuLazyFrame::try_from_value(value)?;
                     let lazy = NuLazyFrame::new(
@@ -271,7 +271,7 @@ macro_rules! lazy_expr_command {
                 call: &Call,
                 input: PipelineData,
             ) -> Result<PipelineData, ShellError> {
-                let value = input.into_value(call.head);
+                let value = input.into_value(call.head)?;
                 if NuDataFrame::can_downcast(&value) {
                     let lazy = NuLazyFrame::try_from_value(value)?;
                     let lazy = NuLazyFrame::new(

crates/nu-cmd-dataframe/src/dataframe/expressions/otherwise.rs

@@ -91,7 +91,7 @@ impl Command for ExprOtherwise {
         let otherwise_predicate: Value = call.req(engine_state, stack, 0)?;
         let otherwise_predicate = NuExpression::try_from_value(otherwise_predicate)?;
 
-        let value = input.into_value(call.head);
+        let value = input.into_value(call.head)?;
         let complete: NuExpression = match NuWhen::try_from_value(value)? {
             NuWhen::Then(then) => then.otherwise(otherwise_predicate.into_polars()).into(),
             NuWhen::ChainedThen(chained_when) => chained_when

crates/nu-cmd-dataframe/src/dataframe/expressions/quantile.rs

@@ -67,7 +67,7 @@ impl Command for ExprQuantile {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let value = input.into_value(call.head);
+        let value = input.into_value(call.head)?;
         let quantile: f64 = call.req(engine_state, stack, 0)?;
 
         let expr = NuExpression::try_from_value(value)?;

crates/nu-cmd-dataframe/src/dataframe/expressions/when.rs

@@ -103,7 +103,7 @@ impl Command for ExprWhen {
         let then_predicate: Value = call.req(engine_state, stack, 1)?;
         let then_predicate = NuExpression::try_from_value(then_predicate)?;
 
-        let value = input.into_value(call.head);
+        let value = input.into_value(call.head)?;
         let when_then: NuWhen = match value {
             Value::Nothing { .. } => when(when_predicate.into_polars())
                 .then(then_predicate.into_polars())

crates/nu-cmd-dataframe/src/dataframe/lazy/explode.rs

@@ -100,7 +100,7 @@ impl Command for LazyExplode {
 }
 
 pub(crate) fn explode(call: &Call, input: PipelineData) -> Result<PipelineData, ShellError> {
-    let value = input.into_value(call.head);
+    let value = input.into_value(call.head)?;
     if NuDataFrame::can_downcast(&value) {
         let df = NuLazyFrame::try_from_value(value)?;
         let columns: Vec<String> = call

crates/nu-cmd-dataframe/src/dataframe/lazy/fill_nan.rs

@@ -82,7 +82,7 @@ impl Command for LazyFillNA {
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
         let fill: Value = call.req(engine_state, stack, 0)?;
-        let value = input.into_value(call.head);
+        let value = input.into_value(call.head)?;
 
         if NuExpression::can_downcast(&value) {
             let expr = NuExpression::try_from_value(value)?;

crates/nu-cmd-dataframe/src/dataframe/lazy/fill_null.rs

@@ -59,7 +59,7 @@ impl Command for LazyFillNull {
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
         let fill: Value = call.req(engine_state, stack, 0)?;
-        let value = input.into_value(call.head);
+        let value = input.into_value(call.head)?;
 
         if NuExpression::can_downcast(&value) {
             let expr = NuExpression::try_from_value(value)?;

crates/nu-cmd-dataframe/src/dataframe/lazy/join.rs

@@ -219,7 +219,7 @@ impl Command for LazyJoin {
         let suffix: Option<String> = call.get_flag(engine_state, stack, "suffix")?;
         let suffix = suffix.unwrap_or_else(|| "_x".into());
 
-        let value = input.into_value(call.head);
+        let value = input.into_value(call.head)?;
         let lazy = NuLazyFrame::try_from_value(value)?;
         let from_eager = lazy.from_eager;
         let lazy = lazy.into_polars();

crates/nu-cmd-dataframe/src/dataframe/lazy/quantile.rs

@@ -54,7 +54,7 @@ impl Command for LazyQuantile {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let value = input.into_value(call.head);
+        let value = input.into_value(call.head)?;
         let quantile: f64 = call.req(engine_state, stack, 0)?;
 
         let lazy = NuLazyFrame::try_from_value(value)?;

crates/nu-cmd-dataframe/src/dataframe/series/masks/is_not_null.rs

@@ -68,7 +68,7 @@ impl Command for IsNotNull {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let value = input.into_value(call.head);
+        let value = input.into_value(call.head)?;
         if NuDataFrame::can_downcast(&value) {
             let df = NuDataFrame::try_from_value(value)?;
             command(engine_state, stack, call, df)

crates/nu-cmd-dataframe/src/dataframe/series/masks/is_null.rs

@@ -68,7 +68,7 @@ impl Command for IsNull {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let value = input.into_value(call.head);
+        let value = input.into_value(call.head)?;
         if NuDataFrame::can_downcast(&value) {
             let df = NuDataFrame::try_from_value(value)?;
             command(engine_state, stack, call, df)

crates/nu-cmd-dataframe/src/dataframe/series/n_unique.rs

@@ -60,7 +60,7 @@ impl Command for NUnique {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let value = input.into_value(call.head);
+        let value = input.into_value(call.head)?;
         if NuDataFrame::can_downcast(&value) {
             let df = NuDataFrame::try_from_value(value)?;
             command(engine_state, stack, call, df)

crates/nu-cmd-dataframe/src/dataframe/series/shift.rs

@@ -56,8 +56,7 @@ impl Command for Shift {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let value = input.into_value(call.head);
-
+        let value = input.into_value(call.head)?;
         if NuLazyFrame::can_downcast(&value) {
             let df = NuLazyFrame::try_from_value(value)?;
             command_lazy(engine_state, stack, call, df)

crates/nu-cmd-dataframe/src/dataframe/series/unique.rs

@@ -72,8 +72,7 @@ impl Command for Unique {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let value = input.into_value(call.head);
-
+        let value = input.into_value(call.head)?;
         if NuLazyFrame::can_downcast(&value) {
             let df = NuLazyFrame::try_from_value(value)?;
             command_lazy(engine_state, stack, call, df)

crates/nu-cmd-dataframe/src/dataframe/test_dataframe.rs

@@ -80,7 +80,8 @@ pub fn test_dataframe_example(engine_state: &mut Box<EngineState>, example: &Exa
     let result =
         eval_block::<WithoutDebug>(engine_state, &mut stack, &block, PipelineData::empty())
             .unwrap_or_else(|err| panic!("test eval error in `{}`: {:?}", example.example, err))
-            .into_value(Span::test_data());
+            .into_value(Span::test_data())
+            .expect("ok value");
 
     println!("input: {}", example.example);
     println!("result: {result:?}");

crates/nu-cmd-dataframe/src/dataframe/values/nu_dataframe/mod.rs

@@ -297,7 +297,7 @@ impl NuDataFrame {
     }
 
     pub fn try_from_pipeline(input: PipelineData, span: Span) -> Result<Self, ShellError> {
-        let value = input.into_value(span);
+        let value = input.into_value(span)?;
         Self::try_from_value(value)
     }
 

crates/nu-cmd-dataframe/src/dataframe/values/nu_expression/mod.rs

@@ -84,7 +84,7 @@ impl NuExpression {
     }
 
     pub fn try_from_pipeline(input: PipelineData, span: Span) -> Result<Self, ShellError> {
-        let value = input.into_value(span);
+        let value = input.into_value(span)?;
         Self::try_from_value(value)
     }
 

crates/nu-cmd-dataframe/src/dataframe/values/nu_lazyframe/mod.rs

@@ -134,7 +134,7 @@ impl NuLazyFrame {
     }
 
     pub fn try_from_pipeline(input: PipelineData, span: Span) -> Result<Self, ShellError> {
-        let value = input.into_value(span);
+        let value = input.into_value(span)?;
         Self::try_from_value(value)
     }
 

crates/nu-cmd-dataframe/src/dataframe/values/nu_lazygroupby/mod.rs

@@ -107,7 +107,7 @@ impl NuLazyGroupBy {
     }
 
     pub fn try_from_pipeline(input: PipelineData, span: Span) -> Result<Self, ShellError> {
-        let value = input.into_value(span);
+        let value = input.into_value(span)?;
         Self::try_from_value(value)
     }
 }