+ t-p-w-w))))
+
+\f
+;; Automatically inform subprocesses of changes to window size.
+
+(defcustom window-adjust-process-window-size-function
+ 'window-adjust-process-window-size-smallest
+ "Control how Emacs chooses inferior process window sizes.
+Emacs uses this function to tell processes the space they have
+available for displaying their output. After each window
+configuration change, Emacs calls the value of
+`window-adjust-process-window-size-function' for each process
+with a buffer being displayed in at least one window.
+This function is responsible for combining the sizes of the
+displayed windows and returning a cons (WIDTH . HEIGHT)
+describing the width and height with which Emacs will call
+`set-process-window-size' for that process. If the function
+returns `nil', Emacs does not call `set-process-window-size'.
+
+This function is called with the process buffer as the current
+buffer and with two arguments: the process and a list of windows
+displaying process. Modes can make this variable buffer-local;
+additionally, the `adjust-window-size-function' process property
+overrides the global or buffer-local value of
+`window-adjust-process-window-size-function'."
+ :type '(choice
+ (const :tag "Minimum area of any window"
+ window-adjust-process-window-size-smallest)
+ (const :tag "Maximum area of any window"
+ window-adjust-process-window-size-largest)
+ (const :tag "Do not adjust process window sizes" ignore)
+ function)
+ :group 'windows
+ :version "25.1")
+
+(defun window-adjust-process-window-size (reducer process windows)
+ "Adjust the process window size of PROCESS.
+WINDOWS is a list of windows associated with PROCESS. REDUCER is
+a two-argument function used to combine the widths and heights of
+the given windows."
+ (when windows
+ (let ((width (window-body-width (car windows)))
+ (height (window-body-height (car windows))))
+ (dolist (window (cdr windows))
+ (setf width (funcall reducer width (window-body-width window)))
+ (setf height (funcall reducer height (window-body-height window))))
+ (cons width height))))
+
+(defun window-adjust-process-window-size-smallest (process windows)
+ "Adjust the process window size of PROCESS.
+WINDOWS is a list of windows associated with PROCESS. Choose the
+smallest area available for displaying PROCESS's output."
+ (window-adjust-process-window-size #'min process windows))
+
+(defun window-adjust-process-window-size-largest (process windows)
+ "Adjust the process window size of PROCESS.
+WINDOWS is a list of windows associated with PROCESS. Choose the
+largest area available for displaying PROCESS's output."
+ (window-adjust-process-window-size #'max process windows))
+
+(defun window--process-window-list ()
+ "Return an alist mapping processes to associated windows.
+A window is associated with a process if that window is
+displaying that processes's buffer."
+ (let ((processes (process-list))
+ (process-windows nil))
+ (walk-windows
+ (lambda (window)
+ (let ((buffer (window-buffer window))
+ (iter processes))
+ (while (let ((process (car iter)))
+ (if (and (process-live-p process)
+ (eq buffer (process-buffer process)))
+ (let ((procwin (assq process process-windows)))
+ ;; Add this window to the list of windows
+ ;; displaying process.
+ (if procwin
+ (push window (cdr procwin))
+ (push (list process window) process-windows))
+ ;; We found our process for this window, so
+ ;; stop iterating over the process list.
+ nil)
+ (setf iter (cdr iter)))))))
+ 1 t)
+ process-windows))
+
+(defun window--adjust-process-windows ()
+ "Update process window sizes to match the current window configuration."
+ (dolist (procwin (window--process-window-list))
+ (let ((process (car procwin)))
+ (with-demoted-errors "Error adjusting window size: %S"
+ (with-current-buffer (process-buffer process)
+ (let ((size (funcall
+ (or (process-get process 'adjust-window-size-function)
+ window-adjust-process-window-size-function)
+ process (cdr procwin))))
+ (when size
+ (set-process-window-size process (cdr size) (car size)))))))))
+
+(add-hook 'window-configuration-change-hook 'window--adjust-process-windows)
+