fix: relay Signals reset to plugins (#13510)

This PR will close #13501

# Description

This PR expands on [the relay of signals to running plugin
processes](https://github.com/nushell/nushell/pull/13181). The Ctrlc
relay has been generalized to SignalAction::Interrupt and when
reset_signal is called on the main EngineState, a SignalAction::Reset is
now relayed to running plugins.

# User-Facing Changes

The signal handler closure now takes a `signals::SignalAction`, while
previously it took no arguments. The handler will now be called on both
interrupt and reset. The method to register a handler on the plugin side
is now called `register_signal_handler` instead of
`register_ctrlc_handler`
[example](https://github.com/nushell/nushell/pull/13510/files#diff-3e04dff88fd0780a49778a3d1eede092ec729a1264b4ef07ca0d2baa859dad05L38).
This will only affect plugin authors who have started making use of
https://github.com/nushell/nushell/pull/13181, which isn't currently
part of an official release.

The change will also require all of user's plugins to be recompiled in
order that they don't error when a signal is received on the
PluginInterface.

# Testing

```
: example ctrlc
interrupt status: false
waiting for interrupt signal...
^Cinterrupt status: true
peace.
Error:   × Operation interrupted
   ╭─[display_output hook:1:1]
 1 │ if (term size).columns >= 100 { table -e } else { table }
   · ─┬
   ·  ╰── This operation was interrupted
   ╰────

: example ctrlc
interrupt status: false   <-- NOTE status is false
waiting for interrupt signal...
^Cinterrupt status: true
peace.
Error:   × Operation interrupted
   ╭─[display_output hook:1:1]
 1 │ if (term size).columns >= 100 { table -e } else { table }
   · ─┬
   ·  ╰── This operation was interrupted
   ╰────
   ```

crates/nu-protocol/src/engine/engine_state.rs

@@ -2,14 +2,14 @@ use crate::{
     ast::Block,
     debugger::{Debugger, NoopDebugger},
     engine::{
-        ctrlc,
         usage::{build_usage, Usage},
         CachedFile, Command, CommandType, EnvVars, OverlayFrame, ScopeFrame, Stack, StateDelta,
         Variable, Visibility, DEFAULT_OVERLAY_NAME,
     },
     eval_const::create_nu_constant,
-    BlockId, Category, Config, DeclId, FileId, GetSpan, HistoryConfig, Module, ModuleId, OverlayId,
-    ShellError, Signals, Signature, Span, SpanId, Type, Value, VarId, VirtualPathId,
+    BlockId, Category, Config, DeclId, FileId, GetSpan, Handlers, HistoryConfig, Module, ModuleId,
+    OverlayId, ShellError, SignalAction, Signals, Signature, Span, SpanId, Type, Value, VarId,
+    VirtualPathId,
 };
 use fancy_regex::Regex;
 use lru::LruCache;
@@ -86,8 +86,8 @@ pub struct EngineState {
     pub spans: Vec<Span>,
     usage: Usage,
     pub scope: ScopeFrame,
-    pub ctrlc_handlers: Option<ctrlc::Handlers>,
     signals: Signals,
+    pub signal_handlers: Option<Handlers>,
     pub env_vars: Arc<EnvVars>,
     pub previous_env_vars: Arc<HashMap<String, Value>>,
     pub config: Arc<Config>,
@@ -147,7 +147,7 @@ impl EngineState {
                 0,
                 false,
             ),
-            ctrlc_handlers: None,
+            signal_handlers: None,
             signals: Signals::empty(),
             env_vars: Arc::new(
                 [(DEFAULT_OVERLAY_NAME.to_string(), HashMap::new())]
@@ -186,7 +186,10 @@ impl EngineState {
     }
 
     pub fn reset_signals(&mut self) {
-        self.signals.reset()
+        self.signals.reset();
+        if let Some(ref handlers) = self.signal_handlers {
+            handlers.run(SignalAction::Reset);
+        }
     }
 
     pub fn set_signals(&mut self, signals: Signals) {
@@ -272,9 +275,9 @@ impl EngineState {
         #[cfg(feature = "plugin")]
         if !delta.plugins.is_empty() {
             for plugin in std::mem::take(&mut delta.plugins) {
-                // Connect plugins to the ctrlc handlers
-                if let Some(handlers) = &self.ctrlc_handlers {
-                    plugin.clone().configure_ctrlc_handler(handlers)?;
+                // Connect plugins to the signal handlers
+                if let Some(handlers) = &self.signal_handlers {
+                    plugin.clone().configure_signal_handler(handlers)?;
                 }
 
                 // Replace plugins that overlap in identity.

crates/nu-protocol/src/engine/mod.rs

@@ -34,5 +34,3 @@ pub use stack_out_dest::*;
 pub use state_delta::*;
 pub use state_working_set::*;
 pub use variable::*;
-
-pub mod ctrlc;

crates/nu-protocol/src/pipeline/handlers.rs

@@ -1,10 +1,10 @@
 use std::fmt::Debug;
 use std::sync::{Arc, Mutex};
 
-use crate::{engine::Sequence, ShellError};
+use crate::{engine::Sequence, ShellError, SignalAction};
 
 /// Handler is a closure that can be sent across threads and shared.
-pub type Handler = Box<dyn Fn() + Send + Sync>;
+pub type Handler = Box<dyn Fn(SignalAction) + Send + Sync>;
 
 /// Manages a collection of handlers.
 #[derive(Clone)]
@@ -23,16 +23,16 @@ impl Debug for Handlers {
     }
 }
 
-/// Guard that unregisters a handler when dropped.
+/// HandlerGuard that unregisters a handler when dropped.
 #[derive(Clone)]
-pub struct Guard {
+pub struct HandlerGuard {
     /// Unique ID of the handler.
     id: usize,
     /// Reference to the handlers list.
     handlers: Arc<Mutex<Vec<(usize, Handler)>>>,
 }
 
-impl Drop for Guard {
+impl Drop for HandlerGuard {
     /// Drops the `Guard`, removing the associated handler from the list.
     fn drop(&mut self) {
         if let Ok(mut handlers) = self.handlers.lock() {
@@ -41,7 +41,7 @@ impl Drop for Guard {
     }
 }
 
-impl Debug for Guard {
+impl Debug for HandlerGuard {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         f.debug_struct("Guard").field("id", &self.id).finish()
     }
@@ -56,23 +56,23 @@ impl Handlers {
 
     /// Registers a new handler and returns an RAII guard which will unregister the handler when
     /// dropped.
-    pub fn register(&self, handler: Handler) -> Result<Guard, ShellError> {
+    pub fn register(&self, handler: Handler) -> Result<HandlerGuard, ShellError> {
         let id = self.next_id.next()?;
         if let Ok(mut handlers) = self.handlers.lock() {
             handlers.push((id, handler));
         }
 
-        Ok(Guard {
+        Ok(HandlerGuard {
             id,
             handlers: Arc::clone(&self.handlers),
         })
     }
 
     /// Runs all registered handlers.
-    pub fn run(&self) {
+    pub fn run(&self, action: SignalAction) {
         if let Ok(handlers) = self.handlers.lock() {
             for (_, handler) in handlers.iter() {
-                handler();
+                handler(action);
             }
         }
     }
@@ -99,14 +99,14 @@ mod tests {
         let called1_clone = Arc::clone(&called1);
         let called2_clone = Arc::clone(&called2);
 
-        let _guard1 = handlers.register(Box::new(move || {
+        let _guard1 = handlers.register(Box::new(move |_| {
             called1_clone.store(true, Ordering::SeqCst);
         }));
-        let _guard2 = handlers.register(Box::new(move || {
+        let _guard2 = handlers.register(Box::new(move |_| {
             called2_clone.store(true, Ordering::SeqCst);
         }));
 
-        handlers.run();
+        handlers.run(SignalAction::Interrupt);
 
         assert!(called1.load(Ordering::SeqCst));
         assert!(called2.load(Ordering::SeqCst));
@@ -119,7 +119,7 @@ mod tests {
         let called = Arc::new(AtomicBool::new(false));
         let called_clone = Arc::clone(&called);
 
-        let guard = handlers.register(Box::new(move || {
+        let guard = handlers.register(Box::new(move |_| {
             called_clone.store(true, Ordering::Relaxed);
         }));
 
@@ -131,7 +131,7 @@ mod tests {
         // Ensure the handler is removed after dropping the guard
         assert_eq!(handlers.handlers.lock().unwrap().len(), 0);
 
-        handlers.run();
+        handlers.run(SignalAction::Interrupt);
 
         // Ensure the handler is not called after being dropped
         assert!(!called.load(Ordering::Relaxed));

crates/nu-protocol/src/pipeline/mod.rs

@@ -1,4 +1,5 @@
 pub mod byte_stream;
+mod handlers;
 pub mod list_stream;
 mod metadata;
 mod out_dest;
@@ -6,6 +7,7 @@ mod pipeline_data;
 mod signals;
 
 pub use byte_stream::*;
+pub use handlers::*;
 pub use list_stream::*;
 pub use metadata::*;
 pub use out_dest::*;

crates/nu-protocol/src/pipeline/signals.rs

@@ -4,6 +4,8 @@ use std::sync::{
     Arc,
 };
 
+use serde::{Deserialize, Serialize};
+
 /// Used to check for signals to suspend or terminate the execution of Nushell code.
 ///
 /// For now, this struct only supports interruption (ctrl+c or SIGINT).
@@ -75,9 +77,17 @@ impl Signals {
         self.signals.is_none()
     }
 
-    pub(crate) fn reset(&self) {
+    pub fn reset(&self) {
         if let Some(signals) = &self.signals {
             signals.store(false, Ordering::Relaxed);
         }
     }
 }
+
+/// The types of things that can be signaled. It's anticipated this will change as we learn more
+/// about how we'd like signals to be handled.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+pub enum SignalAction {
+    Interrupt,
+    Reset,
+}

crates/nu-protocol/src/plugin/registered.rs

@@ -1,6 +1,6 @@
 use std::{any::Any, sync::Arc};
 
-use crate::{engine::ctrlc, PluginGcConfig, PluginIdentity, PluginMetadata, ShellError};
+use crate::{Handlers, PluginGcConfig, PluginIdentity, PluginMetadata, ShellError};
 
 /// Trait for plugins registered in the [`EngineState`](crate::engine::EngineState).
 pub trait RegisteredPlugin: Send + Sync {
@@ -36,10 +36,7 @@ pub trait RegisteredPlugin: Send + Sync {
     fn as_any(self: Arc<Self>) -> Arc<dyn Any + Send + Sync>;
 
     /// Give this plugin a chance to register for Ctrl-C signals.
-    fn configure_ctrlc_handler(
-        self: Arc<Self>,
-        _handler: &ctrlc::Handlers,
-    ) -> Result<(), ShellError> {
+    fn configure_signal_handler(self: Arc<Self>, _handler: &Handlers) -> Result<(), ShellError> {
         Ok(())
     }
 }