Size PTY against window-screen-lines, not window-body-height

ghostel captured terminal height via `(window-body-height)' — which
divides the window's pixel height by frame char height.  But the
standard `window-adjust-process-window-size-smallest' (and term.el,
vterm, eat all do likewise) divides by `default-line-height' via
`(window-screen-lines)', which respects `face-remapping-alist' and
`:height' on the default face.

When a theme remaps the buffer's default face — `nano-light' /
`nano-dark' bump it ~7% higher than frame default — the two
metrics disagree.  Concrete report (#192): body 1307 px / 27 px
frame char = 48 (window-body-height); 1307 px / 29 px default-line
= 45.069 (window-screen-lines).  Init captures 48, libghostty +
PTY spawn at 48 rows; first redisplay fires
`window-configuration-change-hook' (because body-pixel differs
from the freshly-zeroed `old_body_pixel'), the standard adjust-fn
runs, returns 45, and we issue an immediate startup SIGWINCH down
to 45.  Claude Code's /tui fullscreen sometimes mishandles the
SIGWINCH-during-startup case and ends up with a collapsed input box.

Switch every height-capture site to `floor(window-screen-lines)':
- `ghostel--init-buffer' and `ghostel-exec' (the spawn paths).
- `ghostel--commit-cropped-size' (minibuffer focus return).
- `ghostel-compile.el' init/reconcile (3 sites) — same bug class.

Add the `(max 1 …)' guard on the init-buffer height that
`ghostel-exec' already had, since `floor' of a sub-1 value is a
real (if unlikely) source of a 0-row terminal.

Remove `ghostel--reconcile-display-size' and its
`window-buffer-change-functions' registration (added in b9c12ca).
Now redundant: with init capturing the right metric, the standard
machinery (`window-configuration-change-hook' →
`window--adjust-process-windows' → `--window-adjust-process-window-size')
catches every transition the helper tried to catch — chrome
reshuffles via `init_iterator''s body-pixel comparison
(xdisp.c:3443-3474), buffer migration via `set_window_buffer'
setting `FRAME_WINDOW_CHANGE'.

Fix the "Size sync" block in `ghostel-debug-info' (added in
0b19011): compare `term-rows' against `(floor (window-screen-lines))'
instead of `window-body-height', and surface the
frame-vs-default line-height delta directly so a face-remap shows
up in the report.

Update affected tests to mock `window-screen-lines'.

Author: dakra

lisp/ghostel-compile.el

@@ -548,7 +548,9 @@ so there is no remote-integration round-trip on TRAMP buffers."
   (ghostel--load-module t)
   (let* ((buffer (get-buffer-create name))
          (win (or (get-buffer-window buffer t) (selected-window)))
-         (height (if (window-live-p win) (window-body-height win) 24))
+         (height (if (window-live-p win)
+                     (with-selected-window win (floor (window-screen-lines)))
+                   24))
          (width  (if (window-live-p win) (window-max-chars-per-line win) 80)))
     (with-current-buffer buffer
       ;; Set `default-directory' before `ghostel-mode' so the mode's
@@ -626,7 +628,8 @@ honour custom compile-mode subclasses the caller passed to
       ;; column and look garbled until the user's first resize triggers
       ;; `ghostel--window-adjust-process-window-size'.
       (when (and outwin ghostel--term)
-        (let ((oh (max 1 (window-body-height outwin)))
+        (let ((oh (max 1 (with-selected-window outwin
+                           (floor (window-screen-lines)))))
               (ow (max 1 (window-max-chars-per-line outwin))))
           (ghostel--set-size ghostel--term oh ow)
           (setq ghostel--term-rows oh)))
@@ -659,8 +662,9 @@ honour custom compile-mode subclasses the caller passed to
       ;; window, e.g. `allow-no-window').  Use `window-max-chars-per-line'
       ;; as the canonical width measure, matching `ghostel--spawn-pty'.
       (let* ((height (max 1 (if outwin
-                                (window-body-height outwin)
-                              (window-body-height))))
+                                (with-selected-window outwin
+                                  (floor (window-screen-lines)))
+                              (floor (window-screen-lines)))))
              (width (max 1 (if outwin
                                (window-max-chars-per-line outwin)
                              (window-max-chars-per-line))))

lisp/ghostel-debug.el

@@ -570,11 +570,13 @@ ghostel settings into *ghostel-debug* for pasting into bug reports."
                                     (if copy "active" "off"))))
                 (insert "Term handle:         nil (no terminal)\n"))
               ;; Size sync — surfaces #192-class bugs.
-              ;; If body-rows ≠ term-rows but cur=recorded body pixels, then
-              ;; Emacs already absorbed the chrome change but ghostel didn't
-              ;; reconcile (a real ghostel bug).  If both differ, the next
-              ;; redisplay will fire `window-{size,configuration}-change-hook'
-              ;; and `--window-adjust-process-window-size' will reconcile.
+              ;; Compare term-rows against `floor(window-screen-lines)' (what
+              ;; `window-adjust-process-window-size-smallest' uses), NOT
+              ;; `window-body-height': the latter divides by frame char
+              ;; height while screen-lines divides by `default-line-height'
+              ;; (face-remap-aware).  When a theme remaps the default face
+              ;; height, the two disagree and the body-height comparison
+              ;; cries wolf.
               (when (and term (window-live-p win))
                 (insert "\n--- Size sync ---\n")
                 (let* ((cur-body-px (window-body-height win t))
@@ -584,12 +586,21 @@ ghostel settings into *ghostel-debug* for pasting into bug reports."
                        (screen-lines (with-selected-window win
                                        (window-screen-lines)))
                        (body-rows (window-body-height win))
-                       (rows-match (eql body-rows term-rows))
+                       (frame-ch (frame-char-height))
+                       (default-lh (with-selected-window win
+                                     (default-line-height)))
+                       (target-rows (floor screen-lines))
+                       (rows-match (eql target-rows term-rows))
                        (px-match (eql cur-body-px old-body-px)))
-                  (insert (format "Body rows:           %d (window) vs %s (term) %s\n"
-                                  body-rows term-rows
+                  (insert (format "screen-lines:        %.3f → target %d (term=%s) %s\n"
+                                  screen-lines target-rows term-rows
                                   (if rows-match "[in sync]" "[MISMATCH]")))
-                  (insert (format "window-screen-lines: %s\n" screen-lines))
+                  (insert (format "Body rows (frame):   %d (window-body-height — frame chars)\n"
+                                  body-rows))
+                  (insert (format "Line height:         frame=%d px  default-face=%d px%s\n"
+                                  frame-ch default-lh
+                                  (if (eql frame-ch default-lh) ""
+                                    " [face-remap or theme bumps height]")))
                   (insert (format "Body pixels:         cur=%d  recorded=%d %s\n"
                                   cur-body-px old-body-px
                                   (if px-match "" "[redisplay pending]")))
@@ -599,8 +610,8 @@ ghostel settings into *ghostel-debug* for pasting into bug reports."
                    (rows-match
                     (insert "Diagnosis:           in sync\n"))
                    (px-match
-                    (insert "Diagnosis:           Emacs absorbed the chrome change\n")
-                    (insert "                     but ghostel didn't reconcile (#192)\n"))
+                    (insert "Diagnosis:           Emacs absorbed the change but\n")
+                    (insert "                     ghostel didn't reconcile (#192)\n"))
                    (t
                     (insert "Diagnosis:           pending redisplay; hooks will fire\n")
                     (insert "                     on next paint\n"))))))))

lisp/ghostel.el

@@ -3454,7 +3454,8 @@ window (not when it has just been deselected)."
              ghostel--term
              ghostel--process
              (process-live-p ghostel--process))
-    (let ((height (window-body-height window))
+    (let ((height (with-selected-window window
+                    (floor (window-screen-lines))))
           (width (window-max-chars-per-line window))
           (buf (current-buffer)))
       (unless (and (eql height ghostel--term-rows)
@@ -3471,41 +3472,6 @@ window (not when it has just been deselected)."
           (setq ghostel--redraw-timer nil))
         (let ((ghostel--redraw-resize-active t))
           (ghostel--delayed-redraw buf))))))
-
-(defun ghostel--reconcile-display-size (window)
-  "Reconcile terminal size when this buffer is (re-)displayed in WINDOW.
-Buffer migration to a window of a different size produces no
-window-size-change event — Emacs's `adjust-window-size-function'
-machinery does not fire — but `window-buffer-change-functions' does.
-Catch it here and resize libghostty + PTY to match WINDOW.
-
-Intended for buffer-local `window-buffer-change-functions'.  The
-single-window guard avoids ping-pong if the buffer is shown in two
-differently-sized windows simultaneously — that case is handled by
-the existing `window-adjust-process-window-size-smallest' path."
-  (when (and (window-live-p window)
-             (eq (window-buffer window) (current-buffer))
-             ghostel--term
-             ghostel--process
-             (process-live-p ghostel--process)
-             (= 1 (length (get-buffer-window-list (current-buffer) nil t))))
-    (let ((height (window-body-height window))
-          (width (window-max-chars-per-line window)))
-      (unless (and (eql height ghostel--term-rows)
-                   (eql width ghostel--term-cols))
-        (ghostel--set-size ghostel--term (max 1 height) (max 1 width))
-        (setq ghostel--term-rows height
-              ghostel--term-cols width
-              ghostel--force-next-redraw t)
-        (set-process-window-size ghostel--process
-                                 (max 1 height) (max 1 width))
-        (when ghostel--redraw-timer
-          (cancel-timer ghostel--redraw-timer)
-          (setq ghostel--redraw-timer nil))
-        (let ((ghostel--redraw-resize-active t))
-          (ghostel--delayed-redraw (current-buffer)))))))
-
-
 
 ;;; Major mode
 
@@ -3543,8 +3509,6 @@ the existing `window-adjust-process-window-size-smallest' path."
             #'ghostel--commit-cropped-size nil t)
   (add-hook 'window-buffer-change-functions
             #'ghostel--reshow-snap nil t)
-  (add-hook 'window-buffer-change-functions
-            #'ghostel--reconcile-display-size nil t)
   (ghostel--suppress-interfering-modes)
   (setq ghostel--scroll-intercept-active t)
   ;; Let C-g reach the keymap instead of triggering keyboard-quit.
@@ -3584,17 +3548,31 @@ buffer can be found again after title-tracking renames it."
 (defun ghostel--init-buffer (buffer &optional identity)
   "Initialize BUFFER as a ghostel terminal if no terminal handle exists yet.
 Terminal dimensions come from BUFFER's displayed window when one
-exists, otherwise from the selected window.  Subsequent migrations
-to differently-sized windows are reconciled by
-`ghostel--reconcile-display-size' on `window-buffer-change-functions'.
+exists, otherwise from the selected window.  Height uses
+`window-screen-lines' (the metric the standard
+`adjust-window-size-function' path also uses), not
+`window-body-height'.  The former divides the window's pixel height
+by the buffer's `default-line-height', which respects
+`face-remapping-alist' and `:height' on the default face; the latter
+divides by frame char height.  When a theme remaps default —
+`nano-light' / `nano-dark' do this — the two metrics disagree, and
+using `window-body-height' would size the terminal to N rows only to
+have the standard adjust-fn immediately resize to N-K, sending a
+startup SIGWINCH that some TUI apps (Claude Code's /tui fullscreen)
+handle imperfectly (issue #192).
 IDENTITY, if given, is stored as `ghostel--buffer-identity' so the
 buffer can be found again after title-tracking renames it."
   (with-current-buffer buffer
     (unless ghostel--term
       (ghostel--prepare-buffer buffer identity)
       (let* ((w (or (get-buffer-window buffer t) (selected-window)))
-             (height (if (window-live-p w) (window-body-height w) 24))
-             (width  (if (window-live-p w) (window-max-chars-per-line w) 80)))
+             (height (max 1 (if (window-live-p w)
+                                (with-selected-window w
+                                  (floor (window-screen-lines)))
+                              24)))
+             (width  (max 1 (if (window-live-p w)
+                                (window-max-chars-per-line w)
+                              80))))
         (setq ghostel--term
               (ghostel--new height width ghostel-max-scrollback))
         (setq ghostel--term-rows height)
@@ -3658,7 +3636,11 @@ Signals `user-error' if BUFFER already has a live ghostel process."
   (let ((window (or (get-buffer-window buffer t) (selected-window))))
     (with-current-buffer buffer
       (ghostel--prepare-buffer buffer nil)
-      (let* ((height (max 1 (window-body-height window)))
+      ;; Use `window-screen-lines' (not `window-body-height') so the
+      ;; height matches the unit `window-adjust-process-window-size-smallest'
+      ;; uses — see `ghostel--init-buffer' for why.
+      (let* ((height (max 1 (with-selected-window window
+                              (floor (window-screen-lines)))))
              (width (max 1 (window-max-chars-per-line window)))
              (remote-p (file-remote-p default-directory)))
         (setq ghostel--term