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.

diff --git a/lisp/eshell/esh-cmd.el b/lisp/eshell/esh-cmd.el
index 04d65df4f331593593cae8aa1b48d85e30c39662..14139896dd453247a32df12735ed6fd5241419bb 100644 (file)
--- a/lisp/eshell/esh-cmd.el
+++ b/lisp/eshell/esh-cmd.el
@@ -764,8 +764,7 @@ This macro calls itself recursively, with NOTFIRST non-nil."
               (eshell-set-output-handle ,eshell-output-handle
                                         'append nextproc)
               (eshell-set-output-handle ,eshell-error-handle
-                                        'append nextproc)
-              (setq tailproc (or tailproc nextproc))))
+                                        'append nextproc)))
        ,(let ((head (car pipeline)))
           (if (memq (car head) '(let progn))
               (setq head (car (last head))))
@@ -781,7 +780,9 @@ This macro calls itself recursively, with NOTFIRST non-nil."
               ,(cond ((not notfirst) (quote 'first))
                      ((cdr pipeline) t)
                      (t (quote 'last)))))
-         ,(car pipeline))))))
+          (let ((proc ,(car pipeline)))
+            (setq tailproc (or tailproc proc))
+            proc))))))
 
 (defmacro eshell-do-pipelines-synchronously (pipeline)
   "Execute the commands in PIPELINE in sequence synchronously.

diff --git a/test/lisp/eshell/eshell-tests.el b/test/lisp/eshell/eshell-tests.el
index 542815df80963546c964441551e56c26dfd315b0..7658d5f5517e8a6a5595c69b8349df2c5964cba6 100644 (file)
--- 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)")))