Add filter add/del error to runtime

lib/src/config.rs

@@ -9,6 +9,7 @@ use crate::{
 	action::{Action, PostSpawn, PreSpawn},
 	command::Shell,
 	error::RuntimeError,
+	filter::Filterer,
 	fs::Watcher,
 	handler::Handler,
 };
@@ -81,6 +82,11 @@ impl RuntimeConfig {
 		self
 	}
 
+	pub fn filterer(&mut self, filterer: Arc<dyn Filterer>) -> &mut Self {
+		self.action.filterer = filterer;
+		self
+	}
+
 	/// Set the action handler.
 	///
 	/// TODO: notes on how outcome is read immediately after handler returns

lib/src/error.rs

@@ -1,6 +1,6 @@
 //! Error types for critical, runtime, and specialised errors.
 
-use std::path::PathBuf;
+use std::{collections::HashMap, path::PathBuf};
 
 use miette::Diagnostic;
 use thiserror::Error;
@@ -12,6 +12,7 @@ use tokio::{
 use crate::{
 	action,
 	event::Event,
+	filter::tagged::{Filter, Matcher},
 	fs::{self, Watcher},
 };
 
@@ -158,7 +159,7 @@ pub enum RuntimeError {
 	#[diagnostic(code(watchexec::runtime::clearscreen))]
 	Clearscreen(#[from] clearscreen::Error),
 
-	/// Error received when a filter cannot be parsed.
+	/// Error received when a tagged filter cannot be parsed.
 	#[error("cannot parse filter `{src}`: {err:?}")]
 	#[diagnostic(code(watchexec::runtime::filter_parse))]
 	FilterParse {
@@ -166,6 +167,15 @@ pub enum RuntimeError {
 		err: nom::error::ErrorKind,
 		// TODO: use miette's source snippet feature
 	},
+
+	/// Error received when a filter cannot be added or removed from a tagged filter list.
+	#[error("cannot {action} filter: {err:?}")]
+	#[diagnostic(code(watchexec::runtime::filter_change))]
+	FilterChange {
+		action: &'static str,
+		#[source]
+		err: watch::error::SendError<HashMap<Matcher, Vec<Filter>>>,
+	},
 }
 
 /// Errors occurring from reconfigs.