1 files changed, 84 insertions, 0 deletions
diff --git a/tests/ui/process/process-spawn-failure.rs b/tests/ui/process/process-spawn-failure.rs
new file mode 100644
index 00000000000..0950b044c97
--- /dev/null
+++ b/tests/ui/process/process-spawn-failure.rs
@@ -0,0 +1,84 @@
+//! Tests that repeatedly spawning a failing command does not create zombie processes.
+//! Spawns a deliberately invalid command multiple times, verifies each spawn fails,
+//! then uses `ps` (on Unix) to detect any leftover zombie (defunct) child processes.
+//! Checks Rust's process spawning cleans up resources properly.
+//! Skipped on platforms without `ps` utility.
+
+//@ run-pass
+//@ needs-subprocess
+//@ ignore-vxworks no 'ps'
+//@ ignore-fuchsia no 'ps'
+//@ ignore-nto no 'ps'
+
+#![feature(rustc_private)]
+
+use std::process::Command;
+
+// The output from "ps -A -o pid,ppid,args" should look like this:
+//   PID  PPID COMMAND
+//     1     0 /sbin/init
+//     2     0 [kthreadd]
+// ...
+//  6076  9064 /bin/zsh
+// ...
+//  7164  6076 ./spawn-failure
+//  7165  7164 [spawn-failure] <defunct>
+//  7166  7164 [spawn-failure] <defunct>
+// ...
+//  7197  7164 [spawn-failure] <defunct>
+//  7198  7164 ps -A -o pid,ppid,command
+// ...
+
+#[cfg(unix)]
+fn find_zombies() {
+    extern crate libc;
+    let my_pid = unsafe { libc::getpid() };
+
+    // https://pubs.opengroup.org/onlinepubs/9699919799/utilities/ps.html
+    let ps_cmd_output = Command::new("ps").args(&["-A", "-o", "pid,ppid,args"]).output().unwrap();
+    let ps_output = String::from_utf8_lossy(&ps_cmd_output.stdout);
+    // On AIX, the PPID is not always present, such as when a process is blocked
+    // (marked as <exiting>), or if a process is idle. In these situations,
+    // the PPID column contains a "-" for the respective process.
+    // Filter out any lines that have a "-" as the PPID as the PPID is
+    // expected to be an integer.
+    let filtered_ps: Vec<_> =
+        ps_output.lines().filter(|line| line.split_whitespace().nth(1) != Some("-")).collect();
+
+    for (line_no, line) in filtered_ps.into_iter().enumerate() {
+        if 0 < line_no
+            && 0 < line.len()
+            && my_pid
+                == line
+                    .split(' ')
+                    .filter(|w| 0 < w.len())
+                    .nth(1)
+                    .expect("1st column should be PPID")
+                    .parse()
+                    .ok()
+                    .expect("PPID string into integer")
+            && line.contains("defunct")
+        {
+            panic!("Zombie child {}", line);
+        }
+    }
+}
+
+#[cfg(windows)]
+fn find_zombies() {}
+
+fn main() {
+    let too_long = format!("/NoSuchCommand{:0300}", 0u8);
+
+    let _failures = (0..100)
+        .map(|_| {
+            let mut cmd = Command::new(&too_long);
+            let failed = cmd.spawn();
+            assert!(failed.is_err(), "Make sure the command fails to spawn(): {:?}", cmd);
+            failed
+        })
+        .collect::<Vec<_>>();
+
+    find_zombies();
+    // then _failures goes out of scope
+}