Handle runtime errors properly

src/config/init.rs

@@ -1,15 +1,44 @@
 use std::convert::Infallible;
 
-use miette::Result;
-use watchexec::{config::InitConfig, handler::SyncFnHandler};
+use miette::{Report, Result};
+use tracing::error;
+use watchexec::{
+	config::InitConfig,
+	error::{FsWatcherError, RuntimeError},
+	handler::SyncFnHandler,
+	ErrorHook,
+};
 
 use crate::args::Args;
 
 pub fn init(_args: &Args) -> Result<InitConfig> {
 	let mut config = InitConfig::default();
 	config.on_error(SyncFnHandler::from(
-		|data| -> std::result::Result<(), Infallible> {
-			eprintln!("[[{:?}]]", data);
+		|err: ErrorHook| -> std::result::Result<(), Infallible> {
+			if let RuntimeError::IoError {
+				about: "waiting on process group",
+				..
+			} = err.error
+			{
+				// "No child processes" and such
+				// these are often spurious, so condemn them to --debug only
+				error!("{}", err.error);
+				return Ok(());
+			}
+
+			if let RuntimeError::FsWatcher {
+				err:
+					FsWatcherError::Create { .. }
+					| FsWatcherError::TooManyWatches { .. }
+					| FsWatcherError::TooManyHandles { .. },
+				..
+			} = err.error
+			{
+				err.elevate();
+				return Ok(());
+			}
+
+			eprintln!("[[Error (not fatal)]]\n{}", Report::new(err.error));
 			Ok(())
 		},
 	));

src/config/runtime.rs

@@ -226,7 +226,7 @@ pub fn runtime(args: &Args, command_order: Vec<&'static str>) -> Result<RuntimeC
 
 				if let Some(runs) = quit_after_n.clone() {
 					if runs.load(Ordering::SeqCst) == 0 {
-						debug!("quitting after n triggers");
+						eprintln!("[[--quit after n--]]");
 						action.outcome(Outcome::Exit);
 						return fut;
 					}