fix ProcStatus::status_value in pipeline after ctrl-z

Repro (with default prompt):

	$ HOME=$PWD target/debug/fish -C '
	  function sleep_func; sleep 1; false; end
	  commandline "sleep 2 | sleep 3 | sleep 4 | sleep_func"
	  '
	Welcome to fish, the friendly interactive shell
	Type help for instructions on how to use fish
	johannes@e15 ~> sleep 2 | sleep 3 | sleep 4 | sleep_func
	^Zfish: Job 1, 'sleep 2 | sleep 3 | sleep 4 | s…' has stopped
	johannes@e15 ~ [0|SIGTSTP|SIGTSTP|1]> 

I'm not sure why the first sleep is not reported as stopped.

Co-authored-by: Lieuwe Rooijakkers <lieuwerooijakkers@gmail.com>

Fixes issue #12301

Closes #12550

src/proc.rs

@@ -25,7 +25,7 @@
 use libc::{
     _SC_CLK_TCK, EXIT_SUCCESS, SIG_IGN, SIGABRT, SIGBUS, SIGFPE, SIGILL, SIGINT, SIGPIPE, SIGQUIT,
     SIGSEGV, SIGSYS, SIGTTOU, STDOUT_FILENO, WCONTINUED, WEXITSTATUS, WIFCONTINUED, WIFEXITED,
-    WIFSIGNALED, WIFSTOPPED, WNOHANG, WTERMSIG, WUNTRACED,
+    WIFSIGNALED, WIFSTOPPED, WNOHANG, WSTOPSIG, WTERMSIG, WUNTRACED,
 };
 use nix::{
     sys::{
@@ -195,6 +195,11 @@ pub fn signal_exited(&self) -> bool {
         WIFSIGNALED(self.status())
     }
 
+    pub fn stop_signal(&self) -> libc::c_int {
+        assert!(self.stopped(), "Process is not signal stopped");
+        WSTOPSIG(self.status())
+    }
+
     /// Return the signal code, given that we signal exited.
     pub fn signal_code(&self) -> libc::c_int {
         assert!(self.signal_exited(), "Process is not signal exited");
@@ -218,8 +223,10 @@ pub fn status_value(&self) -> i32 {
             128 + self.signal_code()
         } else if self.normal_exited() {
             i32::from(self.exit_code())
+        } else if self.stopped() {
+            128 + self.stop_signal()
         } else {
-            panic!("Process is not exited")
+            panic!("Unsupported status value")
         }
     }
 }

tests/pexpects/wait.py

@@ -122,3 +122,12 @@ sendline("wait %5")
 expect_prompt("jobs: No suitable job: %5")
 sendline("kill %1")
 expect_prompt()
+
+# Regression test for #12301
+sendline("function sleep_func; sleep 2s; end")
+expect_prompt()
+sendline("cat | cat | sleep_func > /dev/null")
+sleep(0.2)
+send("\x1a")
+sleep(0.2)
+expect_prompt()