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Merged
tninja merged 1 commit into from
May 15, 2026
+181 −19
Merged

Fix vterm resize rendering for AI sessions #352

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18 changes: 18 additions & 0 deletions ai-code-backends-infra-vterm.el
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Original file line number Diff line number Diff line change
Expand Up @@ -164,6 +164,24 @@ applications write to the normal screen buffer (preserving scrollback)."
(lambda ()
(funcall orig-fun process data)))))))))

(defun ai-code-backends-infra-vterm-flush-render-queue (&optional buffer)
"Immediately render delayed vterm output queued for BUFFER.
When BUFFER is nil, flush the queue for the current buffer."
(when (or (null buffer) (buffer-live-p buffer))
(with-current-buffer (or buffer (current-buffer))
(when ai-code-backends-infra--vterm-render-timer
(cancel-timer ai-code-backends-infra--vterm-render-timer))
(setq ai-code-backends-infra--vterm-render-timer nil)
(when ai-code-backends-infra--vterm-render-queue
(let ((data ai-code-backends-infra--vterm-render-queue))
(setq ai-code-backends-infra--vterm-render-queue nil)
(when-let* ((process (get-buffer-process (current-buffer)))
((process-live-p process)))
(let ((ai-code-backends-infra-vterm-anti-flicker nil))
(ai-code-backends-infra--vterm-render-preserving-copy-mode-view
(lambda ()
(vterm--filter process data))))))))))

(defun ai-code-backends-infra--vterm-smart-renderer (orig-fun process input)
"Update vterm display via smart rendering around ORIG-FUN.
Activity tracking for notifications is handled separately by
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38 changes: 30 additions & 8 deletions ai-code-backends-infra.el
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Original file line number Diff line number Diff line change
Expand Up @@ -486,9 +486,10 @@ MULTILINE-INPUT-SEQUENCE configures `S-<return>' and `C-<return>' when non-nil."

;;; Reflow and Window Management

(defun ai-code-backends-infra--terminal-resize-handler ()
"Retrieve the terminal's resize handling function based on backend."
(pcase ai-code-backends-infra-terminal-backend
(defun ai-code-backends-infra--terminal-resize-handler (&optional backend)
"Retrieve the resize handling function for BACKEND.
When BACKEND is nil, use `ai-code-backends-infra-terminal-backend'."
(pcase (or backend ai-code-backends-infra-terminal-backend)
('vterm (ai-code-backends-infra-vterm-resize-handler))
('eat (ai-code-backends-infra-eat-resize-handler))
('ghostel (ai-code-backends-infra-ghostel-resize-handler))
Expand All @@ -502,7 +503,8 @@ MULTILINE-INPUT-SEQUENCE configures `S-<return>' and `C-<return>' when non-nil."
(defun ai-code-backends-infra--terminal-reflow-filter (original-fn &rest args)
"Filter terminal reflows to prevent height-only resize triggers.
Suppress reflow when terminal width is unchanged or when the session
buffer is in scroll/copy mode, working around bug #1422."
buffer is in scroll/copy mode, working around bug #1422.
ORIGINAL-FN and ARGS are the resize handler and arguments."
(let* ((base-result (apply original-fn args))
(dimensions-stable t))
(dolist (win (window-list))
Expand Down Expand Up @@ -533,7 +535,7 @@ buffer is in scroll/copy mode, working around bug #1422."
"Add or remove terminal reflow advice according to current settings."
(let* ((resize-handler (ai-code-backends-infra--terminal-resize-handler))
(enabled (and ai-code-backends-infra-prevent-reflow-glitch
(memq ai-code-backends-infra-terminal-backend '(vterm eat)))))
(eq ai-code-backends-infra-terminal-backend 'eat))))
(dolist (handler (cl-copy-list ai-code-backends-infra--reflow-advised-handlers))
(unless (and enabled (eq handler resize-handler))
(when (advice-member-p #'ai-code-backends-infra--terminal-reflow-filter
Expand All @@ -542,6 +544,13 @@ buffer is in scroll/copy mode, working around bug #1422."
#'ai-code-backends-infra--terminal-reflow-filter))
(setq ai-code-backends-infra--reflow-advised-handlers
(delq handler ai-code-backends-infra--reflow-advised-handlers))))
(unless enabled
(when (advice-member-p #'ai-code-backends-infra--terminal-reflow-filter
resize-handler)
(advice-remove resize-handler
#'ai-code-backends-infra--terminal-reflow-filter))
(setq ai-code-backends-infra--reflow-advised-handlers
(delq resize-handler ai-code-backends-infra--reflow-advised-handlers)))
(when (and enabled resize-handler)
(unless (advice-member-p #'ai-code-backends-infra--terminal-reflow-filter
resize-handler)
Expand Down Expand Up @@ -594,9 +603,22 @@ from the window where it was initially created."
(when (and buffer window (buffer-live-p buffer) (window-live-p window))
(with-current-buffer buffer
(when-let ((proc (get-buffer-process buffer)))
(let ((height (window-body-height window))
(width (window-body-width window)))
(set-process-window-size proc height width))))))
(let ((backend (ai-code-backends-infra--current-terminal-backend))
(windows (or (get-buffer-window-list buffer nil t)
(list window))))
(pcase backend
('vterm
(let ((result
(funcall (ai-code-backends-infra--terminal-resize-handler
'vterm)
proc windows)))
(when result
(ai-code-backends-infra-vterm-flush-render-queue buffer))
result))
(_
(set-process-window-size proc
(window-body-height window)
(window-body-width window)))))))))

;;; Session Helpers

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144 changes: 133 additions & 11 deletions test/test_ai-code-backends-infra.el
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Original file line number Diff line number Diff line change
Expand Up @@ -255,19 +255,22 @@
(should scheduled)))))

(ert-deftest test-ai-code-backends-infra-sync-reflow-filter-advice-vterm ()
"Enable and disable reflow advice for vterm according to toggle."
(let ((handler 'ai-code-backends-infra--test-resize-vterm))
"Do not install height-only reflow advice for vterm."
(let ((handler 'ai-code-backends-infra--test-resize-vterm)
(ai-code-backends-infra--reflow-advised-handlers nil))
(fset handler (lambda (&rest args) args))
(unwind-protect
(cl-letf (((symbol-function 'ai-code-backends-infra--terminal-resize-handler)
(lambda () handler)))
(let ((ai-code-backends-infra-terminal-backend 'vterm)
(ai-code-backends-infra-prevent-reflow-glitch t))
(ai-code-backends-infra--sync-reflow-filter-advice)
(should (advice-member-p #'ai-code-backends-infra--terminal-reflow-filter
handler)))
(should-not (advice-member-p #'ai-code-backends-infra--terminal-reflow-filter
handler)))
(advice-add handler :around #'ai-code-backends-infra--terminal-reflow-filter)
(setq ai-code-backends-infra--reflow-advised-handlers nil)
(let ((ai-code-backends-infra-terminal-backend 'vterm)
(ai-code-backends-infra-prevent-reflow-glitch nil))
(ai-code-backends-infra-prevent-reflow-glitch t))
(ai-code-backends-infra--sync-reflow-filter-advice)
(should-not (advice-member-p #'ai-code-backends-infra--terminal-reflow-filter
handler))))
Expand Down Expand Up @@ -317,17 +320,16 @@
('vterm vterm-handler)
('eat eat-handler)
(_ (error "Unexpected backend"))))))
(let ((ai-code-backends-infra-terminal-backend 'vterm)
(ai-code-backends-infra-prevent-reflow-glitch t))
(ai-code-backends-infra--sync-reflow-filter-advice)
(should (advice-member-p #'ai-code-backends-infra--terminal-reflow-filter
vterm-handler)))
(advice-add vterm-handler :around #'ai-code-backends-infra--terminal-reflow-filter)
(setq ai-code-backends-infra--reflow-advised-handlers (list vterm-handler))
(let ((ai-code-backends-infra-terminal-backend 'eat)
(ai-code-backends-infra-prevent-reflow-glitch t)
(ai-code-backends-infra-eat-preserve-position nil))
(ai-code-backends-infra--sync-reflow-filter-advice))
(should-not (advice-member-p #'ai-code-backends-infra--terminal-reflow-filter
vterm-handler)))
vterm-handler))
(should (advice-member-p #'ai-code-backends-infra--terminal-reflow-filter
eat-handler)))
(dolist (handler (list vterm-handler eat-handler))
(when (advice-member-p #'ai-code-backends-infra--terminal-reflow-filter handler)
(advice-remove handler #'ai-code-backends-infra--terminal-reflow-filter))
Expand Down Expand Up @@ -357,6 +359,126 @@
(funcall (cdr (assq 'window-width captured-entry)) 'fake-window)
(should (equal resize-call '(fake-window 4 t)))))))

(ert-deftest test-ai-code-backends-infra-terminal-reflow-filter-ignores-non-ai-vterm-buffer ()
"The reflow filter should pass through non-session vterm buffers."
(with-temp-buffer
(rename-buffer "*vterm*" t)
(let ((ai-code-backends-infra-terminal-backend 'vterm)
(ai-code-backends-infra-prevent-reflow-glitch t)
(original-called nil))
(cl-letf (((symbol-function 'window-list)
(lambda (&rest _args) (list 'fake-window)))
((symbol-function 'window-buffer)
(lambda (_window) (current-buffer))))
(should (eq (ai-code-backends-infra--terminal-reflow-filter
(lambda (&rest _args)
(setq original-called t)
'native-result)
'fake-arg)
'native-result))
(should original-called)))))

(ert-deftest test-ai-code-backends-infra-sync-terminal-dimensions-vterm-height-change ()
"Vterm height changes should go through the native resize handler."
(let* ((buffer (get-buffer-create "*codex[vterm-height-resize]*"))
(process (start-process "ai-code-vterm-resize-test"
buffer
"sleep"
"5"))
(window 'fake-window)
(height 24)
(width 80)
resize-calls
rendered
cancelled-timer)
(unwind-protect
(cl-letf (((symbol-function 'window-live-p)
(lambda (candidate) (eq candidate window)))
((symbol-function 'get-buffer-window-list)
(lambda (_buffer &rest _args) (list window)))
((symbol-function 'window-body-height)
(lambda (_window) height))
((symbol-function 'window-body-width)
(lambda (_window) width))
((symbol-function 'set-process-window-size)
(lambda (&rest _args)
(ert-fail "vterm sync should use the native resize handler")))
((symbol-function 'ai-code-backends-infra--terminal-resize-handler)
(lambda (&optional backend)
(should (eq backend 'vterm))
(lambda (proc windows)
(push (list proc windows height width) resize-calls)
(cons width height))))
((symbol-function 'cancel-timer)
(lambda (timer) (setq cancelled-timer timer)))
((symbol-function 'vterm--filter)
(lambda (proc data)
(push (list proc data ai-code-backends-infra-vterm-anti-flicker)
rendered))))
(with-current-buffer buffer
(setq-local ai-code-backends-infra--session-terminal-backend 'vterm)
(setq-local ai-code-backends-infra--vterm-render-timer 'mock-timer)
(setq-local ai-code-backends-infra--vterm-render-queue "old-redraw-1")
(ai-code-backends-infra--sync-terminal-dimensions buffer window)
(setq height 18)
(setq-local ai-code-backends-infra--vterm-render-queue "old-redraw-2")
(ai-code-backends-infra--sync-terminal-dimensions buffer window)
(should (null ai-code-backends-infra--vterm-render-timer))
(should-not ai-code-backends-infra--vterm-render-queue))
(should (eq cancelled-timer 'mock-timer))
(should (equal (nreverse resize-calls)
`((,process (,window) 24 80)
(,process (,window) 18 80)))))
(should (equal (nreverse rendered)
`((,process "old-redraw-1" nil)
(,process "old-redraw-2" nil))))
(when (process-live-p process)
(delete-process process))
(when (buffer-live-p buffer)
(kill-buffer buffer)))))

(ert-deftest test-ai-code-backends-infra-sync-terminal-dimensions-vterm-width-change ()
"Vterm width changes should go through the native resize handler."
(let* ((buffer (get-buffer-create "*codex[vterm-width-resize]*"))
(process (start-process "ai-code-vterm-width-resize-test"
buffer
"sleep"
"5"))
(window 'fake-window)
(height 24)
(width 80)
calls)
(unwind-protect
(cl-letf (((symbol-function 'window-live-p)
(lambda (candidate) (eq candidate window)))
((symbol-function 'get-buffer-window-list)
(lambda (_buffer &rest _args) (list window)))
((symbol-function 'window-body-height)
(lambda (_window) height))
((symbol-function 'window-body-width)
(lambda (_window) width))
((symbol-function 'set-process-window-size)
(lambda (&rest _args)
(ert-fail "vterm sync should not call generic process sizing")))
((symbol-function 'ai-code-backends-infra--terminal-resize-handler)
(lambda (&optional backend)
(should (eq backend 'vterm))
(lambda (proc windows)
(push (list proc windows height width) calls)
(cons width height)))))
(with-current-buffer buffer
(setq-local ai-code-backends-infra--session-terminal-backend 'vterm)
(ai-code-backends-infra--sync-terminal-dimensions buffer window)
(setq width 100)
(ai-code-backends-infra--sync-terminal-dimensions buffer window))
(should (equal (nreverse calls)
`((,process (,window) 24 80)
(,process (,window) 24 100)))))
(when (process-live-p process)
(delete-process process))
(when (buffer-live-p buffer)
(kill-buffer buffer)))))

(ert-deftest test-ai-code-backends-infra-sync-terminal-cursor-vterm-copy-mode ()
"Show an Emacs cursor in vterm copy mode and restore terminal cursor on exit."
(with-temp-buffer
Expand Down
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