esh-opt.el: Add a :parse-leading-options-only argument (Bug#28323)

* lisp/eshell/esh-opt.el (eshell-eval-using-options): Add a new
:parse-leading-options-only argument which ignores dash/switch
arguments after the first positional argument.
(eshell--process-args): Abort processing of arguments if we see one
positional argument and :parse-leading-options-only is set.
* lisp/eshell/em-tramp.el (eshell/sudo): Use
:parse-leading-options-only, to avoid parsing subcommand switches as
switches of sudo itself.
* test/lisp/eshell/esh-opt-tests.el: Add tests for new and old behavior.

3 files changed, 139 insertions, 3 deletions

diff --git a/lisp/eshell/em-tramp.el b/lisp/eshell/em-tramp.el
index 004c4954908..9475f4ed949 100644
--- a/lisp/eshell/em-tramp.el
+++ b/lisp/eshell/em-tramp.el
@@ -107,6 +107,7 @@ Uses the system sudo through TRAMP's sudo method."
      '((?h "help" nil nil "show this usage screen")
        (?u "user" t user "execute a command as another USER")
        :show-usage
+       :parse-leading-options-only
        :usage "[(-u | --user) USER] COMMAND
 Execute a COMMAND as the superuser or another USER.")
      (throw 'eshell-external
diff --git a/lisp/eshell/esh-opt.el b/lisp/eshell/esh-opt.el
index 67b7d05985d..80eb15359a2 100644
--- a/lisp/eshell/esh-opt.el
+++ b/lisp/eshell/esh-opt.el
@@ -80,6 +80,10 @@ arguments, some do not.  The recognized :KEYWORDS are:
   If present, do not pass MACRO-ARGS through `eshell-flatten-list'
 and `eshell-stringify-list'.
 
+:parse-leading-options-only
+  If present, do not parse dash or switch arguments after the first
+positional argument.  Instead, treat them as positional arguments themselves.
+
 For example, OPTIONS might look like:
 
    ((?C  nil         nil multi-column    \"multi-column display\")
@@ -245,12 +249,19 @@ switch is unrecognized."
                                              (list sym)))))
                                      options)))
          (ai 0) arg
-         (eshell--args args))
-    (while (< ai (length eshell--args))
+         (eshell--args args)
+         (pos-argument-found nil))
+    (while (and (< ai (length eshell--args))
+                ;; Abort if we saw the first pos argument and option is set
+                (not (and pos-argument-found
+                          (memq :parse-leading-options-only options))))
       (setq arg (nth ai eshell--args))
       (if (not (and (stringp arg)
                     (string-match "^-\\(-\\)?\\(.*\\)" arg)))
-          (setq ai (1+ ai))
+          ;; Positional argument found, skip
+          (setq ai (1+ ai)
+                pos-argument-found t)
+        ;; dash or switch argument found, parse
         (let* ((dash (match-string 1 arg))
                (switch (match-string 2 arg)))
           (if (= ai 0)
diff --git a/test/lisp/eshell/esh-opt-tests.el b/test/lisp/eshell/esh-opt-tests.el
new file mode 100644
index 00000000000..13b522b389e
--- /dev/null
+++ b/test/lisp/eshell/esh-opt-tests.el
@@ -0,0 +1,124 @@
+;;; tests/esh-opt-tests.el --- esh-opt test suite
+
+;; Copyright (C) 2018 Free Software Foundation, Inc.
+
+;; 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/>.
+
+;;; Code:
+
+(require 'ert)
+(require 'esh-opt)
+
+(ert-deftest esh-opt-process-args-test ()
+  "Unit tests which verify correct behavior of `eshell--process-args'."
+  (should
+   (equal '(t)
+          (eshell--process-args
+           "sudo"
+           '("-a")
+           '((?a "all" nil show-all "")))))
+  (should
+   (equal '(nil)
+          (eshell--process-args
+           "sudo"
+           '("-g")
+           '((?a "all" nil show-all "")))))
+  (should
+   (equal '("root" "world")
+          (eshell--process-args
+           "sudo"
+           '("-u" "root" "world")
+           '((?u "user" t user "execute a command as another USER")))))
+  (should
+   (equal '(nil "emerge" "-uDN" "world")
+          (eshell--process-args
+           "sudo"
+           '("emerge" "-uDN" "world")
+           '((?u "user" t user "execute a command as another USER")
+             :parse-leading-options-only))))
+  (should
+   (equal '("root" "emerge" "-uDN" "world")
+          (eshell--process-args
+           "sudo"
+           '("-u" "root" "emerge" "-uDN" "world")
+           '((?u "user" t user "execute a command as another USER")
+             :parse-leading-options-only))))
+  (should
+   (equal '("world" "emerge")
+          (eshell--process-args
+           "sudo"
+           '("-u" "root" "emerge" "-uDN" "world")
+           '((?u "user" t user "execute a command as another USER"))))))
+
+(ert-deftest test-eshell-eval-using-options ()
+  "Tests for `eshell-eval-using-options'."
+  (eshell-eval-using-options
+   "sudo" '("-u" "root" "whoami")
+   '((?u "user" t user "execute a command as another USER")
+     :parse-leading-options-only)
+   (should (equal user "root")))
+  (eshell-eval-using-options
+   "sudo" '("--user" "root" "whoami")
+   '((?u "user" t user "execute a command as another USER")
+     :parse-leading-options-only)
+   (should (equal user "root")))
+
+  (eshell-eval-using-options
+   "sudo" '("emerge" "-uDN" "world")
+   '((?u "user" t user "execute a command as another USER"))
+   (should (equal user "world")))
+  (eshell-eval-using-options
+   "sudo" '("emerge" "-uDN" "world")
+   '((?u "user" t user "execute a command as another USER")
+     :parse-leading-options-only)
+   (should (eq user nil)))
+
+  (eshell-eval-using-options
+   "ls" '("-I" "*.txt" "/dev/null")
+   '((?I "ignore" t ignore-pattern
+         "do not list implied entries matching pattern"))
+   (should (equal ignore-pattern "*.txt")))
+
+  (eshell-eval-using-options
+   "ls" '("-l" "/dev/null")
+   '((?l nil long-listing listing-style
+         "use a long listing format"))
+   (should (eql listing-style 'long-listing)))
+  (eshell-eval-using-options
+   "ls" '("/dev/null")
+   '((?l nil long-listing listing-style
+         "use a long listing format"))
+   (should (eq listing-style nil)))
+
+  (eshell-eval-using-options
+   "ls" '("/dev/null" "-h")
+   '((?h "human-readable" 1024 human-readable
+         "print sizes in human readable format"))
+   (should (eql human-readable 1024)))
+  (eshell-eval-using-options
+   "ls" '("/dev/null" "--human-readable")
+   '((?h "human-readable" 1024 human-readable
+         "print sizes in human readable format"))
+   (should (eql human-readable 1024)))
+  (eshell-eval-using-options
+   "ls" '("/dev/null")
+   '((?h "human-readable" 1024 human-readable
+         "print sizes in human readable format"))
+   (should (eq human-readable nil))))
+
+(provide 'esh-opt-tests)
+
+;;; esh-opt-tests.el ends here