bug#27817: 26.0.50; Dired: Support eshell/ls from the beginning if user want to

[Tino Calancha <tino.calancha@gmail.com>]

An user must be able to use Dired with eshell/ls at the
beginning even if s?he doesn't have installed an external
"ls" program.

I) emacs -Q -l em-ls
M-: (progn
      (setq insert-directory-program "foobar-ls"
            eshell-ls-use-in-dired t)
      (dired source-directory)) RET

;; We got an error because `insert-directory-program' was called.
;; Now compare with ls-lisp; in this case `insert-directory-program'
;; is not called.
II) emacs -Q -l ls-lisp
M-: (progn
      (setq insert-directory-program "foobar-ls"
            ls-lisp-use-insert-directory-program nil)
      (dired source-directory)) RET

--8<-----------------------------cut here---------------start------------->8---
commit 6322f2932e9a083e01bb86aa219fc8256443c33f
Author: Tino Calancha <tino.calancha@gmail.com>
Date:   Tue Jul 25 15:46:54 2017 +0900

    Dired: Support eshell/ls from the beginning if user want to
    
    * lisp/dired.el (dired-insert-directory): Check for em-ls as well.
    * test/lisp/dired-tests.el (dired-test-bug27817): Add test.

diff --git a/lisp/dired.el b/lisp/dired.el
index 9d500a9f52..3b29c7129d 100644
--- a/lisp/dired.el
+++ b/lisp/dired.el
@@ -1207,6 +1207,7 @@ dired-insert-directory
 	 ;; as indicated by `ls-lisp-use-insert-directory-program'.
 	 (not (and (featurep 'ls-lisp)
 		   (null ls-lisp-use-insert-directory-program)))
+         (not (and (featurep 'eshell) (bound-and-true-p eshell-ls-use-in-dired)))
 	 (or (if (eq dired-use-ls-dired 'unspecified)
 		 ;; Check whether "ls --dired" gives exit code 0, and
 		 ;; save the answer in `dired-use-ls-dired'.
diff --git a/test/lisp/dired-tests.el b/test/lisp/dired-tests.el
index 69331457c0..601d65768b 100644
--- a/test/lisp/dired-tests.el
+++ b/test/lisp/dired-tests.el
@@ -175,5 +175,18 @@
           (should (looking-at "src")))
       (when (buffer-live-p buf) (kill-buffer buf)))))
 
+(ert-deftest dired-test-bug27817 ()
+  "Test for http://debbugs.gnu.org/27817 ."
+  (require 'em-ls)
+  (let ((orig eshell-ls-use-in-dired)
+        (dired-use-ls-dired 'unspecified)
+        buf insert-directory-program)
+    (unwind-protect
+        (progn
+          (customize-set-variable 'eshell-ls-use-in-dired t)
+          (should (setq buf (dired source-directory))))
+      (customize-set-variable 'eshell-ls-use-in-dired orig)
+      (and (buffer-live-p buf) (kill-buffer)))))
+
 (provide 'dired-tests)
 ;; dired-tests.el ends here

--8<-----------------------------cut here---------------end--------------->8---
In GNU Emacs 26.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.11)
 of 2017-07-25
Repository revision: 565cfd9f6c19e4d2aa318efdf19bdc56175bd153