Ensure that tailproc is set for the last process in an Eshell pipeline

In particular, this used to fail for pipelines where the last process
in the pipeline came from the first element of the pipeline. This
could happen when a process was piped to an ordinary Lisp function,
like in '*echo hi | echo bye'.

* lisp/eshell/esh-cmd.el (eshell-do-pipelines): Set the tailproc even
for the first process in the pipeline.

* test/lisp/eshell/eshell-tests.el (eshell-test/pipe-tailproc): New
test.

1 files changed, 7 insertions, 0 deletions

diff --git a/test/lisp/eshell/eshell-tests.el b/test/lisp/eshell/eshell-tests.el
index 542815df809..7658d5f5517 100644
--- a/test/lisp/eshell/eshell-tests.el
+++ b/test/lisp/eshell/eshell-tests.el
@@ -129,6 +129,13 @@ e.g. \"{(+ 1 2)} 3\" => 3"
    (eshell-command-result-p "echo ${echo hi}-${*echo there}"
                             "hi-there\n")))
 
+(ert-deftest eshell-test/pipe-tailproc ()
+  "Check that piping a process to a non-process command waits for the process"
+  (skip-unless (executable-find "echo"))
+  (with-temp-eshell
+   (eshell-command-result-p "*echo hi | echo bye"
+                            "bye\nhi\n")))
+
 (ert-deftest eshell-test/window-height ()
   "$LINES should equal (window-height)"
   (should (eshell-test-command-result "= $LINES (window-height)")))