8 files changed, 167 insertions, 85 deletions

diff --git a/README.multi-tty b/README.multi-tty
index 9f3e048e2e2..346d27102bf 100644
--- a/README.multi-tty
+++ b/README.multi-tty
@@ -412,7 +412,10 @@ THINGS TO DO
 
         make_terminal_frame
                 create_tty_output
-        
+
+** Decide whether to keep the C implementation of terminal parameters,
+   or revert to the previous, purely Lisp code.  It turned out that
+   local environments do not need terminal parameters after all.
 
 ** Move Fsend_string_to_terminal to term.c, and declare get_named_tty
    as static, removing it from dispextern.h.
@@ -1362,5 +1365,16 @@ DIARY OF CHANGES
    `getenv' and `setenv', and the new `local-environment-variables'
    facility.  Yay!)
 
+   (Updated in patch-465 to fix the semantics of let-binding
+   `process-environment'.  `process-environment' was changed to
+   override all local/global environment variables, and a new variable
+   `global-environment' was introduced to have `process-environment's
+   old meaning.)
+
+   (Updated in patch-466 to fix the case when two emacsclient sessions
+   share the same terminal, but have different environment.  The local
+   environment lists are now stored as frame parameters, so the
+   C-level terminal parameters are not strictly necessary any more.)
+
 ;;; arch-tag: 8da1619e-2e79-41a8-9ac9-a0485daad17d
 
diff --git a/lisp/env.el b/lisp/env.el
index 7099a72ca2c..38a9e865283 100644
--- a/lisp/env.el
+++ b/lisp/env.el
@@ -55,7 +55,7 @@ If it is also not t, RET does not exit if it does non-null completion."
                                      (substring enventry 0
                                                 (string-match "=" enventry)))))
                            (append process-environment
-                                   (terminal-parameter nil 'environment)
+                                   (frame-parameter (frame-with-environment) 'environment)
                                    global-environment))
                    nil mustmatch nil 'read-envvar-name-history))
 
@@ -94,7 +94,7 @@ Use `$$' to insert a single dollar sign."
 
 ;; Fixme: Should the environment be recoded if LC_CTYPE &c is set?
 
-(defun setenv (variable &optional value unset substitute-env-vars terminal)
+(defun setenv (variable &optional value unset substitute-env-vars frame)
   "Set the value of the environment variable named VARIABLE to VALUE.
 VARIABLE should be a string.  VALUE is optional; if not provided or
 nil, the environment variable VARIABLE will be removed.  UNSET
@@ -112,12 +112,15 @@ Interactively, always replace environment variables in the new value.
 If VARIABLE is set in `process-environment', then this function
 modifies its value there.  Otherwise, this function works by
 modifying either `global-environment' or the environment
-belonging to the terminal device of the selected frame, depending
-on the value of `local-environment-variables'.
+belonging to the selected frame, depending on the value of
+`local-environment-variables'.
 
-If optional parameter TERMINAL is non-nil, then it should be a
-terminal id or a frame.  If the specified terminal device has its own
-set of environment variables, this function will modify VAR in it.
+If optional parameter FRAME is non-nil, then it should be a a
+frame.  If the specified frame has its own set of environment
+variables, this function will modify VARIABLE in it.  Note that
+frames on the same terminal device usually share their
+environment, so calling `setenv' on one of them affects the
+others as well.
 
 As a special case, setting variable `TZ' calls `set-time-zone-rule' as
 a side-effect."
@@ -153,9 +156,11 @@ a side-effect."
       (error "Environment variable name `%s' contains `='" variable))
   (let ((pattern (concat "\\`" (regexp-quote variable) "\\(=\\|\\'\\)"))
         (case-fold-search nil)
-        (terminal-env (terminal-parameter terminal 'environment))
+        (frame-env (frame-parameter (frame-with-environment frame) 'environment))
+        (frame-forced (not frame))
         (scan process-environment)
         found)
+    (setq frame (frame-with-environment frame))
     (if (string-equal "TZ" variable)
         (set-time-zone-rule value))
     (block nil
@@ -166,55 +171,54 @@ a side-effect."
               (setcar scan (concat variable "=" value))
             ;; Leave unset variables in `process-environment',
             ;; otherwise the overridden value in `global-environment'
-            ;; or terminal-env would become unmasked.
+            ;; or frame-env would become unmasked.
             (setcar scan variable))
           (return value))
         (setq scan (cdr scan)))
 
       ;; Look in the local or global environment, whichever is relevant.
-      (let ((local-var-p (and terminal-env
-                              (or terminal
+      (let ((local-var-p (and frame-env
+                              (or frame-forced
                                   (eq t local-environment-variables)
                                   (member variable local-environment-variables)))))
         (setq scan (if local-var-p
-                       terminal-env
+                       frame-env
                      global-environment))
         (while scan
           (when (string-match pattern (car scan))
             (if value
                 (setcar scan (concat variable "=" value))
               (if local-var-p
-                  (set-terminal-parameter terminal 'environment
-                                          (delq (car scan) terminal-env))
-                (setq global-environment (delq (car scan) global-environment)))
-              (return value)))
+                  (set-frame-parameter frame 'environment
+                                       (delq (car scan) frame-env))
+                (setq global-environment (delq (car scan) global-environment))))
+            (return value))
           (setq scan (cdr scan)))
 
         ;; VARIABLE is not in any environment list.
         (if value
             (if local-var-p
-                (set-terminal-parameter nil 'environment
-                                        (cons (concat variable "=" value)
-                                              terminal-env))
+                (set-frame-parameter frame 'environment
+                                     (cons (concat variable "=" value)
+                                           frame-env))
               (setq global-environment
                     (cons (concat variable "=" value)
                           global-environment))))
         (return value)))))
 
-(defun getenv (variable &optional terminal)
+(defun getenv (variable &optional frame)
   "Get the value of environment variable VARIABLE.
 VARIABLE should be a string.  Value is nil if VARIABLE is undefined in
 the environment.  Otherwise, value is a string.
 
-If optional parameter TERMINAL is non-nil, then it should be a
-terminal id or a frame.  If the specified terminal device has its own
-set of environment variables, this function will look up VARIABLE in
-it.
+If optional parameter FRAME is non-nil, then it should be a
+frame.  If the specified terminal device has its own set of
+environment variables, this function will look up VARIABLE in it.
 
-Otherwise, this function searches `process-environment' for VARIABLE.
-If it was not found there, then it continues the search in either
-`global-environment' or the local environment list of the current
-terminal device, depending on the value of
+Otherwise, this function searches `process-environment' for
+VARIABLE.  If it was not found there, then it continues the
+search in either `global-environment' or the environment list of
+the selected frame, depending on the value of
 `local-environment-variables'."
   (interactive (list (read-envvar-name "Get environment variable: " t)))
   (let ((value (getenv-internal (if (multibyte-string-p variable)
@@ -236,21 +240,23 @@ variables, only read them.  See `setenv' to do that.
 
 The list is constructed from elements of `process-environment',
 `global-environment' and the local environment list of the
-current terminal, as specified by `local-environment-variables'.
+selected frame, as specified by `local-environment-variables'.
 
 Non-ASCII characters are encoded according to the initial value of
 `locale-coding-system', i.e. the elements must normally be decoded for use.
 See `setenv' and `getenv'."
-  (let ((env (cond ((or (not local-environment-variables)
-                        (not (terminal-parameter nil 'environment)))
-                    (append process-environment global-environment nil))
-                   ((consp local-environment-variables)
-                    (let ((e (reverse process-environment)))
-                      (dolist (entry local-environment-variables)
-                        (setq e (cons (getenv entry) e)))
-                      (append (nreverse e) global-environment nil)))
-                   (t
-                    (append process-environment (terminal-parameter nil 'environment) nil))))
+  (let ((env (let ((local-env (frame-parameter (frame-with-environment)
+                                               'environment)))
+               (cond ((or (not local-environment-variables)
+                          (not local-env))
+                      (append process-environment global-environment nil))
+                     ((consp local-environment-variables)
+                      (let ((e (reverse process-environment)))
+                        (dolist (entry local-environment-variables)
+                          (setq e (cons (getenv entry) e)))
+                        (append (nreverse e) global-environment nil)))
+                     (t
+                      (append process-environment local-env nil)))))
         scan seen)
     ;; Find the first valid entry in env.
     (while (and env (stringp (car env))
diff --git a/lisp/frame.el b/lisp/frame.el
index ecf0697cae4..339100bbff5 100644
--- a/lisp/frame.el
+++ b/lisp/frame.el
@@ -674,12 +674,20 @@ setup is for focus to follow the pointer."
               (cdr (assq 'window-system parameters)))
              (t window-system)))
          (frame-creation-function (cdr (assq w frame-creation-function-alist)))
+         (oldframe (selected-frame))
          frame)
     (unless frame-creation-function
       (error "Don't know how to create a frame on window system %s" w))
     (run-hooks 'before-make-frame-hook)
     (setq frame (funcall frame-creation-function (append parameters (cdr (assq w window-system-default-frame-alist)))))
     (normal-erase-is-backspace-setup-frame frame)
+    ;; Set up the frame-local environment, if needed.
+    (when (eq (frame-display frame) (frame-display oldframe))
+      (let ((env (frame-parameter oldframe 'environment)))
+        (if (not (framep env))
+            (setq env oldframe))
+        (if env
+            (set-frame-parameter frame 'environment env))))
     (run-hook-with-args 'after-make-frame-functions frame)
     frame))
 
diff --git a/lisp/server.el b/lisp/server.el
index fb587b640a3..f98be109c92 100644
--- a/lisp/server.el
+++ b/lisp/server.el
@@ -620,8 +620,8 @@ The following commands are accepted by the client:
                                           ;; emacsclient quits while also preventing
                                           ;; `server-save-buffers-kill-display' from unexpectedly
                                           ;; killing emacs on that frame.
-                                          (list (cons 'client 'nowait))
-                                        (list (cons 'client proc)))))
+                                          (list (cons 'client 'nowait) (cons 'environment env))
+                                        (list (cons 'client proc) (cons 'environment env)))))
                           (setq frame (make-frame-on-display
                                        (or display
                                            (frame-parameter nil 'display)
@@ -637,7 +637,6 @@ The following commands are accepted by the client:
                           (select-frame frame)
                           (server-client-set client 'frame frame)
                           (server-client-set client 'device (frame-display frame))
-                          (set-terminal-parameter frame 'environment env)
                           (setq dontkill t))
                       ;; This emacs does not support X.
                       (server-log "Window system unsupported" proc)
@@ -684,12 +683,12 @@ The following commands are accepted by the client:
                         (setq frame (make-frame-on-tty tty type
                                                        ;; Ignore nowait here; we always need to clean
                                                        ;; up opened ttys when the client dies.
-                                                       `((client . ,proc)))))
+                                                       `((client . ,proc)
+                                                         (environment . ,env)))))
                       (select-frame frame)
                       (server-client-set client 'frame frame)
                       (server-client-set client 'tty (display-name frame))
                       (server-client-set client 'device (frame-display frame))
-                      (set-terminal-parameter frame 'environment env)
 
                       ;; Reply with our pid.
                       (server-send-string proc (concat "-emacs-pid " (number-to-string (emacs-pid)) "\n"))
@@ -740,8 +739,7 @@ The following commands are accepted by the client:
                  ;; -env NAME=VALUE:  An environment variable.
                  ((and (equal "-env" arg) (string-match "\\([^ ]+\\) " request))
                   (let ((var (server-unquote-arg (match-string 1 request))))
-                    (when coding-system
-                      (setq var (decode-coding-string var coding-system)))
+                    ;; XXX Variables should be encoded as in getenv/setenv.
                     (setq request (substring request (match-end 0)))
                     (setq env (cons var env))))
 
diff --git a/src/callproc.c b/src/callproc.c
index ee702fef8c7..715178f8fb2 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -119,7 +119,6 @@ Lisp_Object Vprocess_environment;
 #ifdef DOS_NT
 Lisp_Object Qbuffer_file_type;
 #endif /* DOS_NT */
-Lisp_Object Qenvironment;
 
 /* True iff we are about to fork off a synchronous process or if we
    are waiting for it.  */
@@ -1319,8 +1318,8 @@ child_setup (in, out, err, new_argv, set_pgrp, current_dir)
 
     if (!NILP (Vlocal_environment_variables))
       {
-        local = get_terminal_param (FRAME_DEVICE (XFRAME (selected_frame)),
-                                    Qenvironment);
+        local = get_frame_param (XFRAME (Fframe_with_environment (selected_frame)),
+                                 Qenvironment);
         if (EQ (Vlocal_environment_variables, Qt)
             && !NILP (local))
           environment = local;
@@ -1356,7 +1355,7 @@ child_setup (in, out, err, new_argv, set_pgrp, current_dir)
       new_env = add_env (env, new_env, egetenv (SDATA (XCAR (tem))));
 
     /* The rest of the environment (either Vglobal_environment or the
-       'environment terminal parameter).  */
+       'environment frame parameter).  */
     for (tem = environment;
          CONSP (tem) && STRINGP (XCAR (tem));
          tem = XCDR (tem))
@@ -1488,12 +1487,12 @@ relocate_fd (fd, minfd)
 }
 
 static int
-getenv_internal (var, varlen, value, valuelen, terminal)
+getenv_internal (var, varlen, value, valuelen, frame)
      char *var;
      int varlen;
      char **value;
      int *valuelen;
-     Lisp_Object terminal;
+     Lisp_Object frame;
 {
   Lisp_Object scan;
   Lisp_Object environment = Vglobal_environment;
@@ -1528,17 +1527,19 @@ getenv_internal (var, varlen, value, valuelen, terminal)
     }
 
   /* Find the environment in which to search the variable. */
-  if (!NILP (terminal))
+  if (!NILP (frame))
     {
-      Lisp_Object local = get_terminal_param (get_device (terminal, 1), Qenvironment);
+      CHECK_FRAME (frame);
+      frame = Fframe_with_environment (frame);
+      Lisp_Object local = get_frame_param (XFRAME (frame), Qenvironment);
       /* Use Vglobal_environment if there is no local environment.  */
       if (!NILP (local))
         environment = local;
     }
   else if (!NILP (Vlocal_environment_variables)) 
     {
-      Lisp_Object local = get_terminal_param (FRAME_DEVICE (XFRAME (selected_frame)),
-                                              Qenvironment);
+      Lisp_Object local = get_frame_param (XFRAME (Fframe_with_environment (selected_frame)),
+                                           Qenvironment);
       if (EQ (Vlocal_environment_variables, Qt)
           && !NILP (local))
         environment = local;
@@ -1594,25 +1595,23 @@ DEFUN ("getenv-internal", Fgetenv_internal, Sgetenv_internal, 1, 2, 0,
 VARIABLE should be a string.  Value is nil if VARIABLE is undefined in
 the environment.  Otherwise, value is a string.
 
-If optional parameter TERMINAL is non-nil, then it should be a
-terminal id or a frame.  If the specified terminal device has its own
-set of environment variables, this function will look up VARIABLE in
-it.
+If optional parameter FRAME is non-nil, then it should be a frame.  If
+that frame has its own set of environment variables, this function
+will look up VARIABLE in there.
 
 Otherwise, this function searches `process-environment' for VARIABLE.
 If it was not found there, then it continues the search in either
 `global-environment' or the local environment list of the current
-terminal device, depending on the value of
-`local-environment-variables'.  */)
-     (variable, terminal)
-     Lisp_Object variable, terminal;
+frame, depending on the value of `local-environment-variables'.  */)
+     (variable, frame)
+     Lisp_Object variable, frame;
 {
   char *value;
   int valuelen;
 
   CHECK_STRING (variable);
   if (getenv_internal (SDATA (variable), SBYTES (variable),
-                       &value, &valuelen, terminal))
+                       &value, &valuelen, frame))
     return make_string (value, valuelen);
   else
     return Qnil;
@@ -1842,11 +1841,10 @@ Each element should be a string of the form ENVVARNAME=VALUE.
 The environment which Emacs inherits is placed in this variable when
 Emacs starts.
 
-Some terminal devices may have their own local list of environment
-variables in their 'environment parameter, which may override this
-global list; see `local-environment-variables'.  See
-`process-environment' for a way to modify an environment variable on
-all terminals.
+Some frames may have their own local list of environment variables in
+their 'environment parameter, which may override this global list; see
+`local-environment-variables'.  See `process-environment' for a way to
+modify an environment variable on all frames.
 
 If multiple entries define the same variable, the first one always
 takes precedence.
@@ -1860,12 +1858,12 @@ See `setenv' and `getenv'.  */);
 Each element should be a string of the form ENVVARNAME=VALUE.
 
 Entries in this list take precedence to those in `global-environment'
-or the terminal environment.  (See `local-environment-variables' for
-an explanation of the terminal-local environment.)  Therefore,
-let-binding `process-environment' is an easy way to temporarily change
-the value of an environment variable, irrespective of where it comes
-from.  To use `process-environment' to remove an environment variable,
-include only its name in the list, without "=VALUE".
+or the frame-local environment.  (See `local-environment-variables'.)
+Therefore, let-binding `process-environment' is an easy way to
+temporarily change the value of an environment variable, irrespective
+of where it comes from.  To use `process-environment' to remove an
+environment variable, include only its name in the list, without
+"=VALUE".
 
 This variable is set to nil when Emacs starts.
 
@@ -1886,21 +1884,18 @@ See `setenv' and `getenv'.  */);
   defsubr (&Scall_process_region);
 
   DEFVAR_LISP ("local-environment-variables", &Vlocal_environment_variables,
-               doc: /*  Enable or disable terminal-local environment variables.
+               doc: /*  Enable or disable frame-local environment variables.
 If set to t, `getenv', `setenv' and subprocess creation functions use
-the local environment of the terminal device of the selected frame,
-ignoring `global-environment'.
+the local environment of the selected frame, ignoring
+`global-environment'.
 
 If set to nil, Emacs uses `global-environment' and ignores the
-terminal environment.
+frame-local environment.
 
 Otherwise, `local-environment-variables' should be a list of variable
-names (represented by Lisp strings) to look up in the terminal's
+names (represented by Lisp strings) to look up in the frame's
 environment.  The rest will come from `global-environment'.  */);
   Vlocal_environment_variables = Qnil;
-
-  Qenvironment = intern ("environment");
-  staticpro (&Qenvironment);
 }
 
 /* arch-tag: 769b8045-1df7-4d2b-8968-e3fb49017f95
diff --git a/src/frame.c b/src/frame.c
index c3140628cec..f0657975402 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -111,6 +111,7 @@ Lisp_Object Qbuffer_predicate, Qbuffer_list, Qburied_buffer_list;
 Lisp_Object Qtty_color_mode;
 Lisp_Object Qtty, Qtty_type;
 Lisp_Object Qwindow_system;
+Lisp_Object Qenvironment;
 
 Lisp_Object Qfullscreen, Qfullwidth, Qfullheight, Qfullboth;
 
@@ -1473,6 +1474,24 @@ The functions are run with one arg, the frame to be deleted.  */)
   if (EQ (f->minibuffer_window, echo_area_window))
     echo_area_window = sf->minibuffer_window;
 
+  /* Don't allow other frames to refer to a deleted frame in their
+     'environment parameter.  */
+  {
+    Lisp_Object tail, frame1;
+    Lisp_Object env = get_frame_param (XFRAME (frame), Qenvironment);
+    FOR_EACH_FRAME (tail, frame1)
+      {
+        if (EQ (frame, frame1) || !FRAME_LIVE_P (XFRAME (frame1)))
+          continue;
+        if (EQ (frame, get_frame_param (XFRAME (frame1), Qenvironment)))
+          {
+            store_frame_param (XFRAME (frame1), Qenvironment, env);
+            if (!FRAMEP (env))
+              env = frame1;
+          }
+      }
+  }
+  
   /* Clear any X selections for this frame.  */
 #ifdef HAVE_X_WINDOWS
   if (FRAME_X_P (f))
@@ -2577,6 +2596,43 @@ enabled such bindings for that variable with `make-variable-frame-local'.  */)
 
   return unbind_to (count, Qnil);
 }
+
+DEFUN ("frame-with-environment", Fframe_with_environment, Sframe_with_environment, 0, 1, 0,
+       doc: /* Return the frame that has the environment variable list for FRAME.
+
+The frame-local environment variable list is normally shared between
+frames that were created in the same Emacsclient session.  The
+environment list is stored in a single frame's 'environment parameter;
+the other frames' 'environment parameter is set to this frame.  This
+function follows to chain of 'environment references to reach the
+frame that stores the actual local environment list, and returns that
+frame.  */)
+     (frame)
+     Lisp_Object frame;
+{
+  Lisp_Object hare, tortoise;
+
+  if (NILP (frame))
+    frame = selected_frame;
+  CHECK_FRAME (frame);
+
+  hare = tortoise = get_frame_param (XFRAME (frame), Qenvironment);
+  while (!NILP (hare) && FRAMEP (hare))
+    {
+      frame = hare;
+      hare = get_frame_param (XFRAME (hare), Qenvironment);
+      if (NILP (hare) || !FRAMEP (hare))
+        break;
+      frame = hare;
+      hare = get_frame_param (XFRAME (hare), Qenvironment);
+      tortoise = get_frame_param (XFRAME (tortoise), Qenvironment);
+      if (EQ (hare, tortoise))
+        error ("Cyclic frame-local environment indirection");
+    }
+
+  return frame;
+}
+
 
 DEFUN ("frame-char-height", Fframe_char_height, Sframe_char_height,
        0, 1, 0,
@@ -4232,6 +4288,8 @@ syms_of_frame ()
   staticpro (&Qtty_type);
   Qwindow_system = intern ("window-system");
   staticpro (&Qwindow_system);
+  Qenvironment = intern ("environment");
+  staticpro (&Qenvironment);
   
   Qface_set_after_frame_default = intern ("face-set-after-frame-default");
   staticpro (&Qface_set_after_frame_default);
@@ -4416,6 +4474,7 @@ This variable is local to the current terminal and cannot be buffer-local.  */);
   defsubr (&Sframe_parameters);
   defsubr (&Sframe_parameter);
   defsubr (&Smodify_frame_parameters);
+  defsubr (&Sframe_with_environment);
   defsubr (&Sframe_char_height);
   defsubr (&Sframe_char_width);
   defsubr (&Sframe_pixel_height);
diff --git a/src/frame.h b/src/frame.h
index c63b0bec464..6c54c328923 100644
--- a/src/frame.h
+++ b/src/frame.h
@@ -781,6 +781,7 @@ typedef struct frame *FRAME_PTR;
 extern Lisp_Object Qframep, Qframe_live_p;
 extern Lisp_Object Qtty, Qtty_type;
 extern Lisp_Object Qdevice, Qdisplay_live_p;
+extern Lisp_Object Qenvironment;
 
 extern struct frame *last_nonminibuf_frame;
 
diff --git a/src/lisp.h b/src/lisp.h
index 4b71cd67e98..0aa2d7cb510 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -2998,6 +2998,7 @@ EXFUN (Fvisible_frame_list, 0);
 EXFUN (Fframe_parameter, 2);
 EXFUN (Fframe_parameters, 1);
 EXFUN (Fmodify_frame_parameters, 2);
+EXFUN (Fframe_with_environment, 1);
 EXFUN (Fset_frame_height, 3);
 EXFUN (Fset_frame_width, 3);
 EXFUN (Fset_frame_size, 3);