Do not hardcode "/bin/sh" in compile. Bug#24338, Bug#29723

* doc/emacs/custom.texi (Connection Variables): New node.

* doc/emacs/emacs.texi (Top): Add entry for Connection Variables.

* doc/emacs/misc.texi (Single Shell): Mention default value for
remote buffers.

* doc/lispref/variables.texi (Connection Local Variables):
Describe `with-connection-local-variables' instead of
`with-connection-local-profiles'.

* doc/misc/tramp.texi (Remote processes): Refer to Emacs manual.
Mention default connection-local settings for `shell-file-name'
and `shell-command-switch'.

* etc/NEWS: Mention connection-local variables changes.

* lisp/files-x.el (hack-connection-local-variables):
Push connection-local variables to `file-local-variables-alist'.
(connection-local-criteria-for-default-directory): New defsubst.
(with-connection-local-variables): Rename from
`with-connection-local-profiles'.  Adapt implementation.

* lisp/files.el (hack-local-variables):
Call `hack-connection-local-variables'.

* lisp/shell.el (shell): Use `with-connection-local-variables'.

* lisp/subr.el (start-file-process-shell-command):
* lisp/progmodes/compile.el (compilation-start):
Use `with-connection-local-variables'.  Do not set "/bin/sh" for
remote buffers, trust settings of `shell-file-name'.  (Bug#24338),
(Bug#29723)

* lisp/net/ange-ftp.el (ange-ftp-compress, ange-ftp-uncompress):
Use `shell-command-switch'.

* lisp/net/tramp-adb.el (tramp-adb-connection-local-default-profile):
New defvar.  Add it to connection-local profiles after loading "shell".

* lisp/net/tramp-integration.el (tramp-compat): Require tramp-compat.
(tramp-compat-exec-path): Do not declare anymore.
(tramp-connection-local-safe-shell-file-names): New defvar.
(tramp-connection-local-default-profile): New defconst.  Activate
it after loading "shell".
(shell-file-name, shell-command-switch): Add safe-local-variable
property.

* lisp/net/tramp-sh.el (tramp-display-escape-sequence-regexp):
Add tramp-autoload cookie.

* test/lisp/files-x-tests.el (remote-shell-file-name):
Add safe-local-variable property to remote-* variables.
(tramp-connection-local-default-profile): Declare.
(files-x-test-with-connection-local-variables):
Rename from `files-x-test-with-connection-local-profiles'.  Adapt
implementation.

* test/lisp/net/tramp-tests.el
(tramp-test34-connection-local-variables): New test.
(tramp-test34-explicit-shell-file-name): Run it also for tramp-adb.
Bind connection-local-{profile,criteria}-alist.  Use tramp-adb
specific `shell-file-name'.  Add safe-local-variable property to
`explicit-shell-file-name' and `explicit-sh-args'.

1 files changed, 32 insertions, 19 deletions

diff --git a/lisp/files-x.el b/lisp/files-x.el
index c9abb695700..eedf630b71f 100644
--- a/lisp/files-x.el
+++ b/lisp/files-x.el
@@ -582,7 +582,7 @@ changed by the user.")
 (setq ignored-local-variables
       (cons 'connection-local-variables-alist ignored-local-variables))
 
-(defvar connection-local-profile-alist '()
+(defvar connection-local-profile-alist nil
   "Alist mapping connection profiles to variable lists.
 Each element in this list has the form (PROFILE VARIABLES).
 PROFILE is the name of a connection profile (a symbol).
@@ -590,7 +590,7 @@ VARIABLES is a list that declares connection-local variables for
 PROFILE.  An element in VARIABLES is an alist whose elements are
 of the form (VAR . VALUE).")
 
-(defvar connection-local-criteria-alist '()
+(defvar connection-local-criteria-alist nil
   "Alist mapping connection criteria to connection profiles.
 Each element in this list has the form (CRITERIA PROFILES).
 CRITERIA is a plist identifying a connection and the application
@@ -685,7 +685,9 @@ This does nothing if `enable-connection-local-variables' is nil."
       ;; Loop over variables.
       (dolist (variable (connection-local-get-profile-variables profile))
         (unless (assq (car variable) connection-local-variables-alist)
-          (push variable connection-local-variables-alist))))))
+          (push variable connection-local-variables-alist))))
+    ;; Push them to `file-local-variables-alist'.
+    (hack-local-variables-filter connection-local-variables-alist nil)))
 
 ;;;###autoload
 (defun hack-connection-local-variables-apply (criteria)
@@ -697,24 +699,35 @@ will not be changed."
         (copy-tree connection-local-variables-alist)))
    (hack-local-variables-apply)))
 
+(defsubst connection-local-criteria-for-default-directory ()
+  "Return a connection-local criteria, which represents `default-directory'."
+  (when (file-remote-p default-directory)
+    `(:application tramp
+       :protocol ,(file-remote-p default-directory 'method)
+       :user     ,(file-remote-p default-directory 'user)
+       :machine  ,(file-remote-p default-directory 'host))))
+
 ;;;###autoload
-(defmacro with-connection-local-profiles (profiles &rest body)
-  "Apply connection-local variables according to PROFILES in current buffer.
+(defmacro with-connection-local-variables (&rest body)
+  "Apply connection-local variables according to `default-directory'.
 Execute BODY, and unwind connection-local variables."
-  (declare (indent 1) (debug t))
-  `(let ((enable-connection-local-variables t)
-         (old-buffer-local-variables (buffer-local-variables))
-	 connection-local-variables-alist connection-local-criteria-alist)
-     (apply 'connection-local-set-profiles nil ,profiles)
-     (hack-connection-local-variables-apply nil)
-     (unwind-protect
-         (progn ,@body)
-       ;; Cleanup.
-       (dolist (variable connection-local-variables-alist)
-	 (let ((elt (assq (car variable) old-buffer-local-variables)))
-	   (if elt
-	       (set (make-local-variable (car elt)) (cdr elt))
-           (kill-local-variable (car variable))))))))
+  (declare (debug t))
+  `(if (file-remote-p default-directory)
+       (let ((enable-connection-local-variables t)
+             (old-buffer-local-variables (buffer-local-variables))
+	     connection-local-variables-alist)
+	 (hack-connection-local-variables-apply
+	  (connection-local-criteria-for-default-directory))
+	 (unwind-protect
+             (progn ,@body)
+	   ;; Cleanup.
+	   (dolist (variable connection-local-variables-alist)
+	     (let ((elt (assq (car variable) old-buffer-local-variables)))
+	       (if elt
+		   (set (make-local-variable (car elt)) (cdr elt))
+		 (kill-local-variable (car variable)))))))
+     ;; No connection-local variables to apply.
+     ,@body))