Wait for all processes in a pipeline before resuming an Eshell command

Previously, we only waited until the tail process was finished, but
now, we wait for all of them.  This is more consistent with other
shells, and prevents some cases of a process's output coming *after*
we continued past its pipeline.

* lisp/eshell/esh-cmd.el (eshell-resume-command): Simplify
conditionals, and check that all the foreground processes are dead
before resuming Eshell command.

* test/lisp/eshell/esh-cmd-tests.el
(esh-cmd-test/pipeline-wait/multi-proc): New test.

1 files changed, 10 insertions, 0 deletions

diff --git a/test/lisp/eshell/esh-cmd-tests.el b/test/lisp/eshell/esh-cmd-tests.el
index 3967910a53d..d625b8a6a5d 100644
--- a/test/lisp/eshell/esh-cmd-tests.el
+++ b/test/lisp/eshell/esh-cmd-tests.el
@@ -154,6 +154,16 @@ bug#59469."
    (eshell-match-command-output "*echo hi | echo bye"
                                 "bye\nhi\n")))
 
+(ert-deftest esh-cmd-test/pipeline-wait/multi-proc ()
+  "Check that a pipeline waits for all its processes before returning."
+  (skip-unless (and (executable-find "echo")
+                    (executable-find "sh")
+                    (executable-find "rev")))
+  (with-temp-eshell
+   (eshell-match-command-output
+    "*echo hello | sh -c 'sleep 1; rev' 1>&2 | *echo goodbye"
+    "goodbye\nolleh\n")))
+
 (ert-deftest esh-cmd-test/pipeline-wait/subcommand ()
   "Check that piping with an asynchronous subcommand waits for the subcommand."
   (skip-unless (and (executable-find "echo")