Add ghostel-query-before-killing defcustom (closes #288)

CHANGELOG.md

@@ -4,6 +4,15 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+### Added
+- `ghostel-query-before-killing` defcustom controls whether Emacs
+  asks for confirmation before killing a live ghostel buffer or
+  exiting Emacs while one is running.  Defaults to `auto`: quiet
+  at the shell prompt, queries while a command is running (via
+  OSC 133 C/D markers).  Set to `t` for always-on confirmation,
+  `nil` to restore the previous never-query behavior.
+  Closes [#288](https://github.com/dakra/ghostel/issues/288).
+
 ## [0.26.0] — 2026-05-13
 
 ### Added

lisp/ghostel.el

@@ -364,13 +364,30 @@ The default, `ghostel--set-title-default', renames the buffer to
   "Kill the buffer when the shell process exits."
   :type 'boolean)
 
+(defcustom ghostel-query-before-killing 'auto
+  "Whether to confirm before killing a live ghostel buffer or exiting Emacs.
+
+The value controls the process query-on-exit flag (see
+`set-process-query-on-exit-flag'), which Emacs honours both when
+killing the buffer and when exiting Emacs while the buffer is live.
+
+t      Always query while the shell process is alive.
+nil    Never query.
+auto   Query only while a shell command is running.  Requires OSC 133 shell
+       integration: at a prompt the flag is nil, and it flips to t between
+       the OSC 133 C (command start) and D (command finish) markers."
+  :type '(choice (const :tag "Always" t)
+                 (const :tag "Never" nil)
+                 (const :tag "While a command is running" auto)))
+
 (defcustom ghostel-exit-functions nil
   "Hook run when the terminal process exits.
 Each function is called with two arguments: the buffer and the
 exit event string."
   :type 'hook)
 
-(defcustom ghostel-command-finish-functions nil
+(defcustom ghostel-command-finish-functions
+  '(ghostel--query-before-killing-on-cmd-finish)
   "Hook run when a shell command finishes (OSC 133 D marker).
 Each function is called with two arguments: the buffer and the
 exit status (an integer, or nil if the shell did not report one).
@@ -388,7 +405,8 @@ non-nil, in which case the error is re-signalled so the debugger
 can fire (standard `with-demoted-errors' semantics)."
   :type 'hook)
 
-(defcustom ghostel-command-start-functions nil
+(defcustom ghostel-command-start-functions
+  '(ghostel--query-before-killing-on-cmd-start)
   "Hook run when a shell command starts running (OSC 133 C marker).
 Each function is called with one argument: the buffer.
 
@@ -4510,6 +4528,24 @@ is non-nil so the debugger fires for hook authors who want it."
        (apply fn args))
      nil)))
 
+(defun ghostel--query-before-killing-on-cmd-start (buf)
+  "Flip the process query-on-exit flag on for BUF while a command runs.
+Active only when `ghostel-query-before-killing' is `auto'.
+Hung off `ghostel-command-start-functions'."
+  (when (eq ghostel-query-before-killing 'auto)
+    (let ((proc (buffer-local-value 'ghostel--process buf)))
+      (when (process-live-p proc)
+        (set-process-query-on-exit-flag proc t)))))
+
+(defun ghostel--query-before-killing-on-cmd-finish (buf _exit)
+  "Clear the process query-on-exit flag on BUF when the command finishes.
+Active only when `ghostel-query-before-killing' is `auto'.
+Hung off `ghostel-command-finish-functions'."
+  (when (eq ghostel-query-before-killing 'auto)
+    (let ((proc (buffer-local-value 'ghostel--process buf)))
+      (when (process-live-p proc)
+        (set-process-query-on-exit-flag proc nil)))))
+
 (defun ghostel--prompt-input-start ()
   "From the start of a `ghostel-prompt' region, move past the prefix.
 If `ghostel-input' begins on the same line, point lands at its
@@ -5969,7 +6005,12 @@ matches the PTY window size, and stores the process in
       ;; Set the PTY's actual window size (ioctl TIOCSWINSZ) so that
       ;; the program's line editor (readline/ZLE) can render properly.
       (set-process-window-size proc height width)
-      (set-process-query-on-exit-flag proc nil)
+      ;; For `auto', start nil — we spawn at a fresh prompt.  The
+      ;; OSC 133 C/D handlers flip the flag while a command runs.
+      (set-process-query-on-exit-flag
+       proc (if (eq ghostel-query-before-killing 'auto)
+                nil
+              ghostel-query-before-killing))
       (process-put proc 'adjust-window-size-function
                    #'ghostel--window-adjust-process-window-size)
       proc)))

test/ghostel-test.el

@@ -4660,6 +4660,79 @@ bind `debug-on-error' to nil."
         (ghostel--osc133-marker "D" "0")
         (should later-ran)))))                                 ; second hook still fired
 
+;; -----------------------------------------------------------------------
+;; Test: ghostel-query-before-killing
+;; -----------------------------------------------------------------------
+
+(defmacro ghostel-test--with-cat-process (var &rest body)
+  "Spawn a long-lived `cat' process bound to VAR, run BODY, then clean up.
+The process is killed and the temp buffer destroyed on exit so the
+flag-flip tests don't leak processes between runs."
+  (declare (indent 1))
+  `(let* ((buf (generate-new-buffer " *ghostel-test-query-cat*"))
+          (,var (make-process :name "ghostel-test-cat"
+                              :buffer buf
+                              :command '("cat")
+                              :connection-type 'pipe
+                              :noquery nil)))
+     (unwind-protect (progn ,@body)
+       (when (process-live-p ,var)
+         (delete-process ,var))
+       (kill-buffer buf))))
+
+(ert-deftest ghostel-test-query-before-killing-auto-toggles ()
+  "`auto' flips the query-on-exit flag around OSC 133 C/D markers."
+  (ghostel-test--with-cat-process proc
+    (with-current-buffer (process-buffer proc)
+      (setq ghostel--process proc)
+      (let ((ghostel-query-before-killing 'auto))
+        (set-process-query-on-exit-flag proc nil)              ; baseline
+        (ghostel--query-before-killing-on-cmd-start (current-buffer))
+        (should (process-query-on-exit-flag proc))             ; command running
+        (ghostel--query-before-killing-on-cmd-finish (current-buffer) 0)
+        (should-not (process-query-on-exit-flag proc))))))     ; back at prompt
+
+(ert-deftest ghostel-test-query-before-killing-nil-is-noop ()
+  "When set to nil, the OSC 133 handlers must not touch the flag."
+  (ghostel-test--with-cat-process proc
+    (with-current-buffer (process-buffer proc)
+      (setq ghostel--process proc)
+      (let ((ghostel-query-before-killing nil))
+        (set-process-query-on-exit-flag proc nil)
+        (ghostel--query-before-killing-on-cmd-start (current-buffer))
+        (should-not (process-query-on-exit-flag proc))         ; unchanged
+        (ghostel--query-before-killing-on-cmd-finish (current-buffer) 0)
+        (should-not (process-query-on-exit-flag proc))))))
+
+(ert-deftest ghostel-test-query-before-killing-t-is-noop ()
+  "When set to t, the OSC 133 handlers must not touch the flag.
+The flag is already t from spawn time, and `auto'-only toggling
+would defeat the user's request to always be asked."
+  (ghostel-test--with-cat-process proc
+    (with-current-buffer (process-buffer proc)
+      (setq ghostel--process proc)
+      (let ((ghostel-query-before-killing t))
+        (set-process-query-on-exit-flag proc t)
+        (ghostel--query-before-killing-on-cmd-start (current-buffer))
+        (should (process-query-on-exit-flag proc))             ; still t
+        (ghostel--query-before-killing-on-cmd-finish (current-buffer) 0)
+        (should (process-query-on-exit-flag proc))))))         ; still t after D
+
+(ert-deftest ghostel-test-query-before-killing-handles-dead-process ()
+  "Handlers must not raise if the process has already exited."
+  (ghostel-test--with-cat-process proc
+    (with-current-buffer (process-buffer proc)
+      (setq ghostel--process proc)
+      (delete-process proc)
+      (let ((ghostel-query-before-killing 'auto))
+        (should-not (condition-case _
+                        (progn (ghostel--query-before-killing-on-cmd-start
+                                (current-buffer))
+                               (ghostel--query-before-killing-on-cmd-finish
+                                (current-buffer) 0)
+                               nil)
+                      (error t)))))))
+
 ;; -----------------------------------------------------------------------
 ;; Test: ghostel-compile--finalize
 ;; -----------------------------------------------------------------------
@@ -15553,6 +15626,10 @@ slip past the unit tests."
     ghostel-test-command-finish-hook-error-isolated
     ghostel-test-command-finish-hook-runs-synchronously
     ghostel-test-command-start-hook-runs-synchronously
+    ghostel-test-query-before-killing-auto-toggles
+    ghostel-test-query-before-killing-nil-is-noop
+    ghostel-test-query-before-killing-t-is-noop
+    ghostel-test-query-before-killing-handles-dead-process
     ghostel-test-compile-finalize-scans-errors
     ghostel-test-compile-finalize-appends-footer
     ghostel-test-compile-finalize-footer-on-failure