Improve handling of deferrable Eshell commands

Now, we use the 'eshell-deferrable' wrapper to wrap a form that returns
a process (or list thereof).  This improves upon the old method, which
failed to handle 'eshell-replace-command' correctly.  In that case,
Eshell would fail to unmark commands as deferrable when necessary
(e.g. for commands in pipelines).

* lisp/eshell/esh-cmd.el (eshell-deferrable-commands): Make into a
defvar.
(eshell-deferrable): New function...
(eshell-structure-basic-command): ... use it.
(eshell-trap-errors): Rename to...
(eshell-do-command): ... this, and use 'eshell-deferrable'.  Update
callers.
(eshell--unmark-deferrable): Remove.  Update callers.
(eshell-execute-pipeline): Remove 'eshell-process-identity'.
(eshell-process-identity, eshell-named-command*, eshell-lisp-command*):
Make obsolete.

* test/lisp/eshell/esh-cmd-tests.el (eshell-test-replace-command): New
function.
(esh-cmd-test/pipeline/replace-command): New test.

1 files changed, 1 insertions, 1 deletions

diff --git a/test/lisp/eshell/em-extpipe-tests.el b/test/lisp/eshell/em-extpipe-tests.el
index c5f1301cd3b..4c3adbc2d90 100644
--- a/test/lisp/eshell/em-extpipe-tests.el
+++ b/test/lisp/eshell/em-extpipe-tests.el
@@ -40,7 +40,7 @@
          ((should-parse (expected)
             `(let ((shell-file-name "sh")
                    (shell-command-switch "-c"))
-               ;; Strip `eshell-trap-errors'.
+               ;; Strip `eshell-do-command'.
                (should (equal ,expected
                               (cadadr (eshell-parse-command input))))))
           (with-substitute-for-temp (&rest body)