fix: reap opener processes instead of leaving them as zombies (#1231)

Opening a file, link, URL or config.json, revealing a path, and the custom
link_file_command all spawned `open` / `xdg-open` / `explorer` and dropped
the Child. Dropping a Child never waits on it, so every one of these clicks
left a defunct process under tty7-app for as long as the GUI ran.

Add `core::proc::spawn_reaped`, which spawns the command and waits on it
from a short-lived thread, and route all six fire-and-forget spawns through
it.

crates/tty7-core/src/core/proc.rs

@@ -67,6 +67,21 @@ pub fn output_within(cmd: &mut Command, timeout: Duration) -> io::Result<Output>
     })
 }
 
+/// Starts a command nobody will read back from — an opener like `open` or
+/// `xdg-open` — and reaps it once it exits. Dropping a `Child` never waits on
+/// it, so each fire-and-forget spawn would otherwise sit as a zombie under
+/// this process until it quits.
+pub fn spawn_reaped(cmd: &mut Command) -> io::Result<u32> {
+    let mut child = cmd.spawn()?;
+    let pid = child.id();
+    std::thread::Builder::new()
+        .name("reap-child".into())
+        .spawn(move || {
+            let _ = child.wait();
+        })?;
+    Ok(pid)
+}
+
 fn drain<R: Read + Send + 'static>(pipe: Option<R>) -> Vec<u8> {
     let mut buf = Vec::new();
     if let Some(mut pipe) = pipe {
@@ -103,6 +118,30 @@ mod tests {
         );
     }
 
+    #[test]
+    fn a_reaped_spawn_leaves_no_zombie_behind() {
+        let pid = spawn_reaped(&mut Command::new("true")).expect("true runs");
+        // WNOWAIT only peeks, so this never collects the child itself: the
+        // pid stops being ours (ECHILD) only once the reaper has waited on it.
+        let deadline = Instant::now() + Duration::from_secs(10);
+        loop {
+            let mut info: libc::siginfo_t = unsafe { std::mem::zeroed() };
+            let rc = unsafe {
+                libc::waitid(
+                    libc::P_PID,
+                    pid as libc::id_t,
+                    &mut info,
+                    libc::WEXITED | libc::WNOHANG | libc::WNOWAIT,
+                )
+            };
+            if rc == -1 && io::Error::last_os_error().raw_os_error() == Some(libc::ECHILD) {
+                break;
+            }
+            assert!(Instant::now() < deadline, "the child was never reaped");
+            std::thread::sleep(REAP_POLL);
+        }
+    }
+
     #[test]
     fn output_larger_than_a_pipe_buffer_does_not_deadlock() {
         let mut cmd = Command::new("sh");

src/core/update.rs

@@ -975,7 +975,8 @@ pub fn open_url(url: &str) {
     } else {
         "xdg-open"
     };
-    if let Err(e) = std::process::Command::new(opener).arg(url).spawn() {
+    if let Err(e) = tty7_core::core::proc::spawn_reaped(std::process::Command::new(opener).arg(url))
+    {
         log::warn!("failed to open {url}: {e}");
     }
 }

src/terminal/view.rs

@@ -8442,7 +8442,7 @@ pub(crate) fn open_file_path(path: &std::path::Path) -> std::io::Result<()> {
     } else {
         "xdg-open"
     };
-    std::process::Command::new(opener).arg(path).spawn()?;
+    tty7_core::core::proc::spawn_reaped(std::process::Command::new(opener).arg(path))?;
     Ok(())
 }
 
@@ -8476,7 +8476,7 @@ pub(crate) fn reveal_file_path(path: &std::path::Path) -> std::io::Result<()> {
         c.arg(path.parent().unwrap_or(path));
         c
     };
-    command.spawn()?;
+    tty7_core::core::proc::spawn_reaped(&mut command)?;
     Ok(())
 }
 
@@ -8496,7 +8496,7 @@ fn run_file_command(
             "link_file_command expanded to nothing",
         ));
     };
-    std::process::Command::new(program).args(args).spawn()?;
+    tty7_core::core::proc::spawn_reaped(std::process::Command::new(program).args(args))?;
     Ok(())
 }
 

src/ui/app.rs

@@ -9146,7 +9146,9 @@ impl Tty7App {
         } else {
             "xdg-open"
         };
-        if let Err(e) = std::process::Command::new(opener).arg(&path).spawn() {
+        if let Err(e) =
+            tty7_core::core::proc::spawn_reaped(std::process::Command::new(opener).arg(&path))
+        {
             log::warn!("failed to open {}: {e}", path.display());
         }
     }

src/ui/code_editor.rs

@@ -734,11 +734,12 @@ fn opens_in_browser(path: &Path) -> bool {
 fn open_in_browser(path: &Path) -> std::io::Result<()> {
     #[cfg(target_os = "macos")]
     if let Some(bundle) = default_browser_bundle_id() {
-        std::process::Command::new("open")
-            .arg("-b")
-            .arg(bundle)
-            .arg(path)
-            .spawn()?;
+        tty7_core::core::proc::spawn_reaped(
+            std::process::Command::new("open")
+                .arg("-b")
+                .arg(bundle)
+                .arg(path),
+        )?;
         return Ok(());
     }
     crate::terminal::view::open_file_path(path)