From 8efc90d9a3a406dc795842bd86174da8e3944874 Mon Sep 17 00:00:00 2001
From: John Shahid <jvshahid@gmail.com>
Date: Sun, 20 Jan 2019 19:08:17 -0500
Subject: [PATCH] Adjust line wrapping on window resize and killing text

* lisp/term.el (term-mode): Advice filter-buffer-substring-function to remove
line wrapping from killed text.
(term-reset-size): Add or remove line wrapping depending on the new terminal
width.
(term-emulate-terminal):
(term-unwrap-line):
---
 lisp/term.el | 46 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 44 insertions(+), 2 deletions(-)

diff --git a/lisp/term.el b/lisp/term.el
index f49777f94c..1406b80fd5 100644
--- a/lisp/term.el
+++ b/lisp/term.el
@@ -1116,6 +1116,9 @@ term-mode
 
   (set (make-local-variable 'font-lock-defaults) '(nil t))
 
+  (add-function :filter-return
+                (local 'filter-buffer-substring-function)
+                'term--filter-buffer-substring)
   (add-function :filter-return
                 (local 'window-adjust-process-window-size-function)
                 (lambda (size)
@@ -1132,9 +1135,32 @@ term-mode
       (setq term-input-ring (make-ring term-input-ring-size)))
   (term-update-mode-line))
 
+(defun term--insert-fake-newline (&optional count)
+  (let ((old-point (point)))
+    (term-insert-char ?\n count)
+    (put-text-property old-point (point) 'term-line-wrap t)))
+
+(defun term--remove-fake-newlines ()
+  (goto-char (point-min))
+  (while (setq fake-newline (next-single-property-change (point)
+                                                         'term-line-wrap))
+    (goto-char fake-newline)
+    (let ((inhibit-read-only t))
+      (delete-char 1))))
+
+(defun term--filter-buffer-substring (content)
+  (with-temp-buffer
+    (insert content)
+    (term--remove-fake-newlines)
+    (buffer-string)))
+
 (defun term-reset-size (height width)
   (when (or (/= height term-height)
             (/= width term-width))
+    ;; Delete all newlines used for wrapping
+    (when (/= width term-width)
+      (save-excursion
+        (term--remove-fake-newlines)))
     (let ((point (point)))
       (setq term-height height)
       (setq term-width width)
@@ -1147,7 +1173,19 @@ term-reset-size
       (setq term-start-line-column nil)
       (setq term-current-row nil)
       (setq term-current-column nil)
-      (goto-char point))))
+      (goto-char point))
+    (save-excursion
+      ;; Add newlines to wrap long lines that are currently displayed
+      (forward-line (- (term-current-row)))
+      (beginning-of-line)
+      (while (not (eobp))
+        (let* ((eol (save-excursion (end-of-line) (current-column))))
+          (when (> eol width)
+            (move-to-column width)
+            (let ((inhibit-read-only t))
+              (term--insert-fake-newline)))
+          (unless (eobp)
+            (forward-char)))))))
 
 ;; Recursive routine used to check if any string in term-kill-echo-list
 ;; matches part of the buffer before point.
@@ -2906,6 +2944,7 @@ term-emulate-terminal
                       (delete-region (point) (line-end-position))
                       (term-down 1 t)
                       (term-move-columns (- (term-current-column)))
+                      (put-text-property (1- (point)) (point) 'term-line-wrap t)
                       (setq decoded-substring
                             (substring decoded-substring (- term-width old-column)))
                       (setq old-column 0)))
@@ -3719,7 +3758,10 @@ term-down
 ;; if the line above point wraps around, add a ?\n to undo the wrapping.
 ;; FIXME:  Probably should be called more than it is.
 (defun term-unwrap-line ()
-  (when (not (bolp)) (insert-before-markers ?\n)))
+  (when (not (bolp))
+    (let ((old-point (point)))
+      (insert-before-markers ?\n)
+      (put-text-property old-point (point) 'term-line-wrap t))))
 
 (defun term-erase-in-line (kind)
   (when (= kind 1) ;; erase left of point
-- 
2.20.1