Add Eshell syntax to more easily bypass Eshell's own pipelining

* etc/NEWS:
* doc/misc/eshell.texi (Input/Output): Document the new syntax.
* lisp/eshell/em-extpipe.el: New module (Bug#46351).
* test/lisp/eshell/em-extpipe-tests.el: New tests.
* lisp/eshell/esh-module.el (eshell-modules-list): Add `eshell-extpipe'.

1 files changed, 205 insertions, 0 deletions

diff --git a/test/lisp/eshell/em-extpipe-tests.el b/test/lisp/eshell/em-extpipe-tests.el
new file mode 100644
index 00000000000..1283b6b361f
--- /dev/null
+++ b/test/lisp/eshell/em-extpipe-tests.el
@@ -0,0 +1,205 @@
+;;; em-extpipe-tests.el --- em-extpipe test suite  -*- lexical-binding:t -*-
+
+;; Copyright (C) 2022 Free Software Foundation, Inc.
+
+;; Author: Sean Whitton <spwhitton@spwhitton.name>
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+
+;;; Code:
+
+(require 'cl-lib)
+(require 'ert)
+(require 'ert-x)
+(require 'em-extpipe)
+(eval-and-compile
+  (load (expand-file-name "eshell-tests-helpers"
+                          (file-name-directory (or load-file-name
+                                                   default-directory)))))
+
+(defvar eshell-history-file-name)
+(defvar eshell-test--max-subprocess-time)
+(declare-function eshell-command-result-p "eshell-tests-helpers")
+
+(defmacro em-extpipe-tests--deftest (name input &rest body)
+  (declare (indent 2))
+  `(ert-deftest ,name ()
+     (cl-macrolet
+         ((should-parse (expected)
+            `(let ((shell-file-name "sh")
+                   (shell-command-switch "-c"))
+               ;; Strip `eshell-trap-errors'.
+               (should (equal ,expected
+                              (cadr (eshell-parse-command input))))))
+          (with-substitute-for-temp (&rest body)
+            ;; Substitute name of an actual temporary file and/or
+            ;; buffer into `input'.  The substitution logic is
+            ;; appropriate for only the use we put it to in this file.
+            `(ert-with-temp-file temp
+               (let ((temp-buffer (generate-new-buffer " *temp*" t)))
+                 (unwind-protect
+                     (let ((input
+                            (replace-regexp-in-string
+                             "temp\\([^>]\\|\\'\\)" temp
+                             (string-replace "#<buffer temp>"
+                                             (buffer-name temp-buffer)
+                                             input))))
+                       ,@body)
+                   (when (buffer-name temp-buffer)
+                     (kill-buffer temp-buffer))))))
+          (temp-should-string= (expected)
+            `(string= ,expected (string-trim-right
+                                 (with-temp-buffer
+                                   (insert-file-contents temp)
+                                   (buffer-string)))))
+          (temp-buffer-should-string= (expected)
+            `(string= ,expected (string-trim-right
+                                 (with-current-buffer temp-buffer
+                                   (buffer-string))))))
+       (skip-unless shell-file-name)
+       (skip-unless shell-command-switch)
+       (skip-unless (executable-find shell-file-name))
+       (let ((input ,input))
+         (with-temp-eshell ,@body)))))
+
+(em-extpipe-tests--deftest em-extpipe-test-1
+    "echo \"bar\" *| rev >temp"
+  (skip-unless (executable-find "rev"))
+  (should-parse '(eshell-named-command
+                  "sh" (list "-c" "echo \"bar\" | rev >temp")))
+  (with-substitute-for-temp
+   (eshell-command-result-p input "^$")
+   (temp-should-string= "rab")))
+
+(em-extpipe-tests--deftest em-extpipe-test-2
+    "echo \"bar\" | rev *>temp"
+  (skip-unless (executable-find "rev"))
+  (should-parse
+   '(eshell-execute-pipeline
+     '((eshell-named-command "echo" (list (eshell-escape-arg "bar")))
+       (eshell-named-command "sh" (list "-c" "rev >temp")))))
+  (with-substitute-for-temp
+   (eshell-command-result-p input "^$")
+   (temp-should-string= "rab")))
+
+(em-extpipe-tests--deftest em-extpipe-test-3 "foo *| bar | baz -d"
+  (should-parse
+   '(eshell-execute-pipeline
+     '((eshell-named-command "sh" (list "-c" "foo | bar"))
+       (eshell-named-command "baz" (list "-d"))))))
+
+(em-extpipe-tests--deftest em-extpipe-test-4
+    "echo \"bar\" *| rev >#<buffer temp>"
+  (skip-unless (executable-find "rev"))
+  (should-parse
+   '(progn
+      (ignore
+       (eshell-set-output-handle 1 'overwrite
+				 (get-buffer-create "temp")))
+      (eshell-named-command "sh"
+			    (list "-c" "echo \"bar\" | rev"))))
+  (with-substitute-for-temp
+   (eshell-command-result-p input "^$")
+   (temp-buffer-should-string= "rab")))
+
+(em-extpipe-tests--deftest em-extpipe-test-5
+    "foo *| bar >#<buffer quux> baz"
+  (should-parse '(eshell-named-command
+                  "sh" (list "-c" "foo | bar >#<buffer quux> baz"))))
+
+(em-extpipe-tests--deftest em-extpipe-test-6
+    "foo >#<buffer quux> *| bar baz"
+  (should-parse '(eshell-named-command
+                  "sh" (list "-c" "foo >#<buffer quux> | bar baz"))))
+
+(em-extpipe-tests--deftest em-extpipe-test-7
+    "foo *| bar >#<buffer quux> >>#<process other>"
+  (should-parse
+   '(progn
+      (ignore
+       (eshell-set-output-handle 1 'overwrite
+				 (get-buffer-create "quux")))
+      (ignore
+       (eshell-set-output-handle 1 'append
+				 (get-process "other")))
+      (eshell-named-command "sh"
+			    (list "-c" "foo | bar")))))
+
+(em-extpipe-tests--deftest em-extpipe-test-8
+    "foo *| bar >/dev/kill | baz"
+  (should-parse
+   '(eshell-execute-pipeline
+     '((progn
+	 (ignore
+	  (eshell-set-output-handle 1 'overwrite "/dev/kill"))
+	 (eshell-named-command "sh"
+			       (list "-c" "foo | bar")))
+       (eshell-named-command "baz")))))
+
+(em-extpipe-tests--deftest em-extpipe-test-9 "foo \\*| bar"
+  (should-parse
+   '(eshell-execute-pipeline
+     '((eshell-named-command "foo"
+                             (list (eshell-escape-arg "*")))
+       (eshell-named-command "bar")))))
+
+(em-extpipe-tests--deftest em-extpipe-test-10 "foo \"*|\" *>bar"
+  (should-parse
+   '(eshell-named-command "sh" (list "-c" "foo \"*|\" >bar"))))
+
+(em-extpipe-tests--deftest em-extpipe-test-11 "foo '*|' bar"
+  (should-parse '(eshell-named-command
+                  "foo" (list (eshell-escape-arg "*|") "bar"))))
+
+(em-extpipe-tests--deftest em-extpipe-test-12 ">foo bar *| baz"
+  (should-parse
+   '(eshell-named-command "sh" (list "-c" ">foo bar | baz"))))
+
+(em-extpipe-tests--deftest em-extpipe-test-13 "foo*|bar"
+  (should-parse '(eshell-execute-pipeline
+                  '((eshell-named-command (concat "foo" "*"))
+                    (eshell-named-command "bar")))))
+
+(em-extpipe-tests--deftest em-extpipe-test-14 "tac *<temp"
+  (skip-unless (executable-find "tac"))
+  (should-parse '(eshell-named-command "sh" (list "-c" "tac <temp")))
+  (with-substitute-for-temp
+   (with-temp-buffer (insert "bar\nbaz\n") (write-file temp))
+   (eshell-command-result-p input "baz\nbar")))
+
+(em-extpipe-tests--deftest em-extpipe-test-15 "echo \"bar\" *| cat"
+  (skip-unless (executable-find "cat"))
+  (should-parse
+   '(eshell-named-command "sh" (list "-c" "echo \"bar\" | cat")))
+  (cl-letf (((symbol-function 'eshell/cat)
+             (lambda (&rest _args) (eshell-print "nonsense"))))
+    (eshell-command-result-p input "bar")
+    (eshell-command-result-p "echo \"bar\" | cat" "nonsense")))
+
+(em-extpipe-tests--deftest em-extpipe-test-16 "echo \"bar\" *| rev"
+  (skip-unless (executable-find "rev"))
+  (should-parse
+   '(eshell-named-command "sh" (list "-c" "echo \"bar\" | rev")))
+  (let ((eshell-prefer-lisp-functions t))
+    (cl-letf (((symbol-function 'rev)
+               (lambda (&rest _args) (eshell-print "nonsense"))))
+      (eshell-command-result-p input "rab")
+      (eshell-command-result-p "echo \"bar\" | rev" "nonsense"))))
+
+;;; em-extpipe-tests.el ends here