refactor(term): F12 opens eshell-through-EAT, retire eshell-toggle and xterm-color

Point the F12 dock-and-remember toggle at eshell instead of a standalone EAT zsh shell, so the primary terminal is eshell running through EAT (eat-eshell-mode): elisp functions as commands, TRAMP transparency, and EAT rendering visual commands. Drop the eshell-toggle package and its C-<f12> binding, since F12 covers it now. Drop xterm-color from eshell, since EAT handles ANSI color natively and its TERM=xterm-256color fought EAT's own. The toggle's buffer predicate now matches eshell-mode; the toggle tests and fixture are updated.

4 files changed, 62 insertions, 76 deletions

diff --git a/modules/eat-config.el b/modules/eat-config.el
index d44fbfba3..7f3eab69f 100644
--- a/modules/eat-config.el
+++ b/modules/eat-config.el
@@ -1,13 +1,18 @@
-;;; eat-config.el --- EAT terminal and the F12 toggle -*- lexical-binding: t; coding: utf-8; -*-
+;;; eat-config.el --- EAT terminal emulator and the F12 eshell toggle -*- lexical-binding: t; coding: utf-8; -*-
 
 ;;; Commentary:
 ;;
-;; EAT (Emulate A Terminal, pure elisp) is the F12 terminal.  Because EAT renders
-;; entirely in elisp, its whole palette is real Emacs faces, so it themes from
-;; the theme.  This module owns the eat package configuration, the keymap wiring
-;; that lets F12 and C-; reach Emacs from inside a terminal, and the F12
+;; EAT (Emulate A Terminal, pure elisp) is the terminal emulator.  Because EAT
+;; renders entirely in elisp, its whole palette is real Emacs faces, so it themes
+;; from the theme.  This module owns the eat package configuration, the keymap
+;; wiring that lets F12 and C-; reach Emacs from inside a terminal, and the F12
 ;; dock-and-remember toggle.
 ;;
+;; F12 opens eshell, which runs through EAT (eat-eshell-mode, set up in
+;; eshell-config.el): the shell is eshell -- elisp functions as commands, TRAMP
+;; transparency -- and EAT renders its visual commands.  eshell-config.el holds
+;; the shell itself; this module holds the emulator and the toggle.
+;;
 ;; The toggle reuses the geometry-preservation pattern from cj-window-toggle-lib:
 ;; capture direction + body size at toggle-off, replay them via a custom display
 ;; action using frame-edge directions and body-relative sizes, so the docked
@@ -19,9 +24,10 @@
 (require 'cj-window-toggle-lib)
 
 (declare-function eat "eat" (&optional program arg))
-(defvar eat-buffer-name)
+(declare-function eshell "eshell" (&optional arg))
 (defvar eat-mode-map)
 (defvar eat-semi-char-mode-map)
+(defvar eshell-buffer-name)
 (defvar cj/custom-keymap)
 
 (defun cj/turn-off-chrome-for-term ()
@@ -114,18 +120,14 @@ Positive integer: body-cols (right/left) or total-lines (below/above) -- see
 nil means fall back to `cj/term-toggle-window-height' as a fraction.")
 
 (defun cj/--term-toggle-buffer-p (buffer)
-  "Return non-nil when BUFFER is the EAT terminal F12 should manage.
+  "Return non-nil when BUFFER is an eshell terminal F12 should manage.
 
-Qualifies when BUFFER is alive and has `eat-mode' (or its name starts with the
-EAT buffer-name prefix).  ai-term's ghostel agent buffers never match -- they
-are managed separately via M-SPC, not F12."
+F12 opens eshell, which runs through EAT via eat-eshell-mode.  ai-term's ghostel
+agent buffers are managed separately via M-SPC, not F12."
   (and (bufferp buffer)
        (buffer-live-p buffer)
        (with-current-buffer buffer
-         (or (eq major-mode 'eat-mode)
-             (string-prefix-p (or (bound-and-true-p eat-buffer-name)
-                                  "*eat*")
-                              (buffer-name buffer))))))
+         (derived-mode-p 'eshell-mode))))
 
 (defun cj/--term-toggle-buffers ()
   "Return live F12-managed terminal buffers in `buffer-list' (MRU) order."
@@ -189,17 +191,15 @@ Returns one of:
          (t '(create-new))))))))
 
 (defun cj/term-toggle ()
-  "Toggle the EAT terminal buffer.
+  "Toggle the F12 eshell terminal (the primary `*eshell*', run through EAT).
 
-- If the EAT terminal is displayed in this frame, capture its geometry and
-  delete its window (toggle off).  Falls back to burying when it is the only
-  window in the frame.
-- Otherwise, if the EAT terminal buffer is alive, display it via the
-  saved-geometry action.
-- Otherwise, create a new EAT terminal, displaying it through the same
-  saved-geometry action.
+- If it is displayed in this frame, capture its geometry and delete its window
+  (toggle off).  Falls back to burying when it is the only window in the frame.
+- Otherwise, if it is alive, display it via the saved-geometry action.
+- Otherwise, open eshell, displaying it through the same saved-geometry action.
 
-ai-term's ghostel agent buffers are managed separately via M-SPC, not F12."
+eshell runs through EAT via eat-eshell-mode, so visual commands render in a real
+terminal.  ai-term's ghostel agent buffers are managed separately via M-SPC."
   (interactive)
   (pcase (cj/--term-toggle-dispatch)
     (`(toggle-off . ,win)
@@ -214,10 +214,10 @@ ai-term's ghostel agent buffers are managed separately via M-SPC, not F12."
        (when w (select-window w)))
      buf)
     (`(create-new)
-     ;; Create the EAT buffer without stealing the layout, then display it
+     ;; Open the primary eshell without stealing the layout, then display it
      ;; through the saved-geometry dock rule (same path as show-recent).
-     (save-window-excursion (eat))
-     (let ((buf (get-buffer (or (bound-and-true-p eat-buffer-name) "*eat*"))))
+     (save-window-excursion (eshell))
+     (let ((buf (get-buffer (or (bound-and-true-p eshell-buffer-name) "*eshell*"))))
        (when buf
          (display-buffer buf)
          (let ((w (get-buffer-window buf)))
diff --git a/modules/eshell-config.el b/modules/eshell-config.el
index 33b900af6..ac583cf70 100644
--- a/modules/eshell-config.el
+++ b/modules/eshell-config.el
@@ -188,35 +188,11 @@ pairs where COMMAND is the `cd' string `eshell/alias' should run."
   (require 'eat)
   (eat-eshell-mode 1))
 
-(use-package eshell-toggle
-  :custom
-  (eshell-toggle-size-fraction 2)
-  (eshell-toggle-run-command nil)
-  (eshell-toggle-init-function #'eshell-toggle-init-eshell)
-  :bind
-  ("C-<f12>" . eshell-toggle))
-
-(use-package xterm-color
-  :after eshell
-  ;; Two hooks. eshell-before-prompt is the real hook name; use-package appends
-  ;; "-hook", so writing eshell-before-prompt-hook here registered on a
-  ;; nonexistent eshell-before-prompt-hook-hook and never ran. The eshell-mode
-  ;; hook scopes TERM=xterm-256color to eshell-spawned processes only (a global
-  ;; setenv would leak it to every start-process regardless of terminal).
-  :hook
-  ((eshell-before-prompt . (lambda ()
-                             (setq xterm-color-preserve-properties t)))
-   (eshell-mode . (lambda ()
-                    (setq-local process-environment
-                                (cons "TERM=xterm-256color"
-                                      process-environment)))))
-  :config
-  ;; Wire xterm-color into eshell's output pipeline (per its README): install
-  ;; the filter and drop eshell's own ANSI handler. Without this the escapes are
-  ;; never interpreted and TERM=xterm-256color only leaks raw codes.
-  (add-to-list 'eshell-preoutput-filter-functions 'xterm-color-filter)
-  (setq eshell-output-filter-functions
-        (remove 'eshell-handle-ansi-color eshell-output-filter-functions)))
+;; eshell-toggle and xterm-color are retired.  F12 opens eshell now (the
+;; dock-and-remember toggle in eat-config.el), and eat-eshell-mode renders
+;; eshell's output through EAT, which handles ANSI color natively -- so
+;; xterm-color's filter and its TERM=xterm-256color override are redundant and
+;; would fight EAT's own TERM=eat-truecolor.
 
 (use-package eshell-syntax-highlighting
   :after esh-mode
diff --git a/tests/test-term-toggle--buffer-filter.el b/tests/test-term-toggle--buffer-filter.el
index 4dae0c8d3..6db2ec65c 100644
--- a/tests/test-term-toggle--buffer-filter.el
+++ b/tests/test-term-toggle--buffer-filter.el
@@ -4,9 +4,9 @@
 ;; Three closely-related helpers determine which terminal buffer F12
 ;; manages: the predicate `cj/--term-toggle-buffer-p', the list
 ;; `cj/--term-toggle-buffers', and the per-frame window finder
-;; `cj/--term-toggle-displayed-window'.  F12 manages the EAT terminal;
-;; ghostel buffers (including ai-term's agent buffers) are NOT F12-managed --
-;; they live on M-SPC.
+;; `cj/--term-toggle-displayed-window'.  F12 opens eshell (run through EAT via
+;; eat-eshell-mode), so it manages eshell-mode buffers.  Standalone eat buffers,
+;; ghostel buffers, and ai-term's agent buffers are NOT F12-managed.
 
 ;;; Code:
 
@@ -22,18 +22,18 @@
   (cj/test--kill-agent-buffers)
   (cj/test--kill-test-term-buffers))
 
-(ert-deftest test-term-toggle--buffer-p-accepts-eat-mode ()
-  "Normal: an eat-mode buffer qualifies as the F12 terminal."
+(ert-deftest test-term-toggle--buffer-p-accepts-eshell-mode ()
+  "Normal: an eshell-mode buffer qualifies as the F12 terminal."
   (test-term-toggle--cleanup)
-  (let ((buf (cj/test--make-fake-eat-buffer "*test-term-1*")))
+  (let ((buf (cj/test--make-fake-eshell-buffer "*test-term-1*")))
     (unwind-protect
         (should (cj/--term-toggle-buffer-p buf))
       (kill-buffer buf))))
 
-(ert-deftest test-term-toggle--buffer-p-rejects-ghostel ()
-  "Boundary: a ghostel buffer is NOT F12-managed (ghostel is ai-term's, M-SPC)."
+(ert-deftest test-term-toggle--buffer-p-rejects-eat ()
+  "Boundary: a standalone eat buffer is NOT F12-managed (F12 opens eshell)."
   (test-term-toggle--cleanup)
-  (let ((buf (cj/test--make-fake-ghostel-buffer "*test-term-ghostel*")))
+  (let ((buf (cj/test--make-fake-eat-buffer "*test-term-eat*")))
     (unwind-protect
         (should-not (cj/--term-toggle-buffer-p buf))
       (kill-buffer buf))))
@@ -47,7 +47,7 @@
       (kill-buffer buf))))
 
 (ert-deftest test-term-toggle--buffer-p-rejects-non-terminal ()
-  "Boundary: a regular buffer (not eat-mode, no terminal name prefix) -> nil."
+  "Boundary: a regular buffer (not eshell-mode) -> nil."
   (test-term-toggle--cleanup)
   (let ((buf (get-buffer-create "*test-term-regular*")))
     (unwind-protect
@@ -57,35 +57,35 @@
 (ert-deftest test-term-toggle--buffer-p-rejects-dead-buffer ()
   "Boundary: nil and dead buffers -> nil."
   (should-not (cj/--term-toggle-buffer-p nil))
-  (let ((buf (cj/test--make-fake-eat-buffer "*test-term-dead*")))
+  (let ((buf (cj/test--make-fake-eshell-buffer "*test-term-dead*")))
     (kill-buffer buf)
     (should-not (cj/--term-toggle-buffer-p buf))))
 
-(ert-deftest test-term-toggle--buffers-returns-eat-excludes-others ()
-  "Normal: returns the EAT terminal but not ghostel/agent buffers."
+(ert-deftest test-term-toggle--buffers-returns-eshell-excludes-others ()
+  "Normal: returns the eshell terminal but not eat/agent buffers."
   (test-term-toggle--cleanup)
-  (let ((eat (cj/test--make-fake-eat-buffer "*test-term-eat*"))
+  (let ((esh (cj/test--make-fake-eshell-buffer "*test-term-esh*"))
         (agent (cj/test--make-fake-ghostel-buffer "agent [for-test]")))
     (unwind-protect
         (let ((result (cj/--term-toggle-buffers)))
-          (should (memq eat result))
+          (should (memq esh result))
           (should-not (memq agent result)))
-      (kill-buffer eat)
+      (kill-buffer esh)
       (kill-buffer agent))))
 
 (ert-deftest test-term-toggle--displayed-window-finds-terminal ()
-  "Normal: the EAT terminal in a window -> returns that window."
+  "Normal: the eshell terminal in a window -> returns that window."
   (test-term-toggle--cleanup)
-  (let ((eat (cj/test--make-fake-eat-buffer "*test-term-shown*")))
+  (let ((esh (cj/test--make-fake-eshell-buffer "*test-term-shown*")))
     (unwind-protect
         (save-window-excursion
           (delete-other-windows)
           (let ((win (split-window-right)))
-            (set-window-buffer win eat)
+            (set-window-buffer win esh)
             (let ((result (cj/--term-toggle-displayed-window)))
               (should (windowp result))
-              (should (eq (window-buffer result) eat)))))
-      (kill-buffer eat))))
+              (should (eq (window-buffer result) esh)))))
+      (kill-buffer esh))))
 
 (ert-deftest test-term-toggle--displayed-window-skips-agent ()
   "Boundary: only an agent terminal is displayed -> nil (agent not F12-managed)."
diff --git a/tests/testutil-ghostel-buffers.el b/tests/testutil-ghostel-buffers.el
index 3c8d75d00..8e26efec4 100644
--- a/tests/testutil-ghostel-buffers.el
+++ b/tests/testutil-ghostel-buffers.el
@@ -56,5 +56,15 @@ predicate without the side-effects of `(eat)'."
       (setq-local major-mode 'eat-mode))
     buf))
 
+(defun cj/test--make-fake-eshell-buffer (name)
+  "Return a buffer named NAME with `major-mode' set to `eshell-mode'.
+
+Avoids starting a real eshell by setting the mode buffer-locally.  Used by the
+F12 toggle tests that need a buffer satisfying the eshell-mode predicate."
+  (let ((buf (get-buffer-create name)))
+    (with-current-buffer buf
+      (setq-local major-mode 'eshell-mode))
+    buf))
+
 (provide 'testutil-ghostel-buffers)
 ;;; testutil-ghostel-buffers.el ends here