Limit right prompt detection logic to the prompt.

Before this change, output containing tabs or otherwise skip characters
would trigger the right prompt detection logic, which would then attempt
to remove from the yanked text what it sees as part of the prompt.

This change restricts right prompt detection to the prompt, the section
with bracketed-paste turned on, so that command output is left alone.

Fixes #21

mistty-term.el

@@ -392,8 +392,7 @@ mistty-reverse-input-decode-map.el to `xterm-function-map'.")
 This variable evaluates to true when bracketed paste is turned on
 by the command that controls, to false otherwise.
 
-This variable is available in the work buffer.")
-
+This variable is available in both the work and term buffers.")
 
 (defvar-local mistty--term-properties-to-add-alist nil
   "An alist of id to text properties to add to the term buffer.
@@ -464,11 +463,13 @@ into `mistty-bracketed-paste' in the buffer WORK-BUFFER.
               (unless (eq ?\n (char-before (point)))
                 (add-text-properties (mistty--bol (point)) (point) props))
               (mistty-register-text-properties 'mistty-bracketed-paste props))
+            (setq mistty-bracketed-paste t)
             (mistty--with-live-buffer work-buffer
               (setq mistty-bracketed-paste t)))
            ((equal ext "[?2004l") ; disable bracketed paste
             (term-emulate-terminal proc (substring str start seq-end))
             (mistty-unregister-text-properties 'mistty-bracketed-paste)
+            (setq mistty-bracketed-paste nil)
             (mistty--with-live-buffer work-buffer
               (setq mistty-bracketed-paste nil)))
            ((equal ext "[?25h") ; make cursor visible
@@ -596,22 +597,23 @@ BEG and END define the region that was modified."
       (put-text-property pos fake-nl-end 'yank-handler '(nil "" nil nil))
       (setq beg fake-nl-end)))
 
-  ;; Detect and mark right prompts.
-  (let ((bol (mistty--bol beg))
-        (eol (mistty--eol beg)))
-    (when (and (> beg bol)
-               (<= end eol)
-               (get-text-property (1- beg) 'mistty-skip)
-               (not (get-text-property bol 'mistty-skip)))
-      (add-text-properties
-       beg end '(mistty-skip t mistty-right-prompt t yank-handler (nil "" nil nil))))))
+  (when mistty-bracketed-paste
+    ;; Detect and mark right prompts.
+    (let ((bol (mistty--bol beg))
+          (eol (mistty--eol beg)))
+      (when (and (> beg bol)
+                 (<= end eol)
+                 (get-text-property (1- beg) 'mistty-skip)
+                 (not (get-text-property bol 'mistty-skip)))
+        (add-text-properties
+         beg end '(mistty-skip t mistty-right-prompt t yank-handler (nil "" nil nil)))))))
 
 (defun mistty--around-move-to-column (orig-fun &rest args)
   "Add property \\='mistty-skip t to spaces added when just moving.
 
 ORIG-FUN is the original `move-to-column' function that's being
 advised and ARGS are its arguments."
-  (if (eq 'term-mode major-mode)
+  (if (and (eq 'term-mode major-mode) mistty-bracketed-paste)
     (let ((initial-end (line-end-position)))
       (apply orig-fun args)
       (when (> (point) initial-end)

test/mistty-test.el

@@ -2823,6 +2823,17 @@
       (yank)
       (should (equal "$ echo hello" (mistty-test-content))))))
 
+(ert-deftest mistty-test-not-right-prompt-yank-in-output ()
+  (mistty-with-test-buffer (:shell fish)
+    (mistty-send-string "printf 'foo\\t") ; \t would confuse mistty-send-text
+    (mistty-send-text "bar\n'")
+    (let ((start (point)))
+      (mistty-send-and-wait-for-prompt)
+      (copy-region-as-kill (mistty--bol start 2) (mistty--eol start 2)))
+    (with-temp-buffer
+      (yank)
+      (should (equal "foo     bar" (mistty-test-content))))))
+
 (ert-deftest mistty-test-fish-right-prompt-skip-empty-spaces-at-prompt ()
   (mistty-with-test-buffer (:shell fish :selected t)
     (mistty-setup-fish-right-prompt)