correctly exit when child exit

Cargo.toml

@@ -11,7 +11,6 @@ serde_json = "1.0"
 anyhow = "1.0"
 lazy_static = "1.4"
 smallvec = "1.11"
-tempfile = "3.9"
 env_logger = "0.10"
 log = "0.4.20"
 
@@ -21,3 +20,4 @@ crate-type = ["cdylib"]
 
 [dev-dependencies]
 emacs = "0.18"
+tempfile = "3.9"

src/app.rs

@@ -86,9 +86,9 @@ fn process_server_reader(reader: impl std::io::Read,
 
 pub fn run_app_forever(client_reader: impl std::io::Read + Send + 'static,
                        client_writer: impl std::io::Write + Send + 'static,
-                       mut server_cmd: std::process::Command) -> Result<()> {
+                       mut server_cmd: std::process::Command) -> Result<std::process::ExitStatus> {
     info!("Running server {:?}", server_cmd);
-    let proc = server_cmd
+    let mut proc = server_cmd
         .stdin(std::process::Stdio::piped())
         .stdout(std::process::Stdio::piped())
         .stderr(std::process::Stdio::inherit())
@@ -98,37 +98,35 @@ pub fn run_app_forever(client_reader: impl std::io::Read + Send + 'static,
     let c2s_channel_counter = Arc::new(AtomicI32::new(0));
     let (s2c_channel_pub, s2c_channel_sub) = mpsc::channel::<String>();
 
-    let threads = vec![
-        {
-            let c2s_channel_counter = c2s_channel_counter.clone();
-            std::thread::spawn(move || {
-                info!("Started client->server write thread");
-                process_channel_to_writer(c2s_channel_sub, Some(c2s_channel_counter), proc.stdin.unwrap()).unwrap();
-                info!("Finished client->server write thread");
-            })
-        },
+    {
+        let c2s_channel_counter = c2s_channel_counter.clone();
+        let proc_stdin = proc.stdin.take().unwrap();
         std::thread::spawn(move || {
-            info!("Started server->client write thread");
-            process_channel_to_writer(s2c_channel_sub, None, client_writer).unwrap();
-            info!("Finished server->client write thread");
-        }),
-        {
-            let s2c_channel_pub = s2c_channel_pub.clone();
-            std::thread::spawn(move || {
-                info!("Started server->client read thread");
-                process_server_reader(proc.stdout.unwrap(), s2c_channel_pub).unwrap();
-                info!("Finished server->client read thread");
-            })
-        },
+            info!("Started client->server write thread");
+            process_channel_to_writer(c2s_channel_sub, Some(c2s_channel_counter), proc_stdin).unwrap();
+            info!("Finished client->server write thread");
+        });
+    }
+    std::thread::spawn(move || {
+        info!("Started server->client write thread");
+        process_channel_to_writer(s2c_channel_sub, None, client_writer).unwrap();
+        info!("Finished server->client write thread");
+    });
+    {
+        let s2c_channel_pub = s2c_channel_pub.clone();
+        let proc_stdout = proc.stdout.take().unwrap();
         std::thread::spawn(move || {
-            info!("Started client->server read thread");
-            process_client_reader(
-                client_reader, c2s_channel_pub, c2s_channel_counter, s2c_channel_pub).unwrap();
-            info!("Finished client->server read thread");
-        }),
-    ];
-
-    threads.into_iter().for_each(|x| x.join().unwrap());
+            info!("Started server->client read thread");
+            process_server_reader(proc_stdout, s2c_channel_pub).unwrap();
+            info!("Finished server->client read thread");
+        });
+    }
+    std::thread::spawn(move || {
+        info!("Started client->server read thread");
+        process_client_reader(
+            client_reader, c2s_channel_pub, c2s_channel_counter, s2c_channel_pub).unwrap();
+        info!("Finished client->server read thread");
+    });
 
-    Ok(())
+    Ok(proc.wait()?)
 }

src/lib.rs

@@ -1,4 +1,4 @@
 pub mod bytecode;
-mod rpcio;
+pub mod rpcio;
 mod lsp_message;
 pub mod app;

src/main.rs

@@ -24,5 +24,6 @@ fn main() -> Result<()> {
     let mut cmd = std::process::Command::new(&args[1]);
     cmd.args(&args[2..]);
 
-    app::run_app_forever(std::io::stdin(), std::io::stdout(), cmd)
+    let exit_status = app::run_app_forever(std::io::stdin(), std::io::stdout(), cmd)?;
+    std::process::exit(exit_status.code().unwrap_or(1))
 }

tests/app_test.rs

@@ -0,0 +1,35 @@
+use anyhow::Result;
+use tempfile;
+use env_logger;
+
+use emacs_lsp_booster::{app, rpcio};
+
+#[test]
+fn test_app_with_echo_server() -> Result<()> {
+    env_logger::init();
+
+    let (input_pair_in, input_pair_out) = std::os::unix::net::UnixStream::pair()?;
+    let tmpdir = tempfile::tempdir()?;
+    let output_file = std::fs::File::create(tmpdir.path().join("output.txt"))?;
+
+    std::thread::spawn(move || {
+        let mut input_bufwriter = std::io::BufWriter::new(input_pair_in);
+        for _ in 0..10 {
+            rpcio::rpc_write(&mut input_bufwriter, "{}").unwrap();
+        }
+        loop {
+            std::thread::park();
+        }
+    });
+
+    let mut cmd = std::process::Command::new("timeout");
+    cmd.args(&["1", "cat"]);
+
+    let exit_status = app::run_app_forever(input_pair_out, output_file, cmd)?;
+    assert!(!exit_status.success());  // timeout kill
+
+    let output = std::fs::read_to_string(tmpdir.path().join("output.txt"))?;
+    assert_eq!(output.chars().filter(|x| *x == '#').count(), 10);
+
+    Ok(())
+}