Fix behavior of Eshell prompt when yanking output into it

* lisp/eshell/esh-util.el (eshell--unmark-string-as-output): New
function...

* lisp/eshell/esh-mode.el (eshell-mode): ... use it.

* test/lisp/eshell/eshell-tests.el (eshell-test/yank-output): New test
(bug#66469).

2 files changed, 11 insertions, 0 deletions

diff --git a/lisp/eshell/esh-mode.el b/lisp/eshell/esh-mode.el
index 2b560afb92c..9d2cd1e67eb 100644
--- a/lisp/eshell/esh-mode.el
+++ b/lisp/eshell/esh-mode.el
@@ -361,6 +361,9 @@ and the hook `eshell-exit-hook'."
   (setq-local eshell-last-output-end (point-marker))
   (setq-local eshell-last-output-block-begin (point))
 
+  (add-function :filter-return (local 'filter-buffer-substring-function)
+                #'eshell--unmark-string-as-output)
+
   (let ((modules-list (copy-sequence eshell-modules-list)))
     (setq-local eshell-modules-list modules-list))
 
diff --git a/lisp/eshell/esh-util.el b/lisp/eshell/esh-util.el
index 4c251a29269..ca2f775318a 100644
--- a/lisp/eshell/esh-util.el
+++ b/lisp/eshell/esh-util.el
@@ -234,6 +234,14 @@ current buffer."
                 (eshell--mark-as-output start1 end1)))))
     (add-hook 'after-change-functions hook nil t)))
 
+(defun eshell--unmark-string-as-output (string)
+  "Unmark STRING as Eshell output."
+  (remove-list-of-text-properties
+   0 (length string)
+   '(rear-nonsticky front-sticky field insert-in-front-hooks)
+   string)
+  string)
+
 (defun eshell-find-delimiter
   (open close &optional bound reverse-p backslash-p)
   "From point, find the CLOSE delimiter corresponding to OPEN.