Ensure that Eshell users can run lines of command output as input

Previously, this failed to work properly because any additional input
the user entered would have no 'field' property, confusing
'eshell-get-old-input'.  To fix this, we simply ensure that any
user-entered text in the output field retains said output field
(bug#61310).

* lisp/eshell/esh-util.el (eshell-command-output-properties): New
variable.
(eshell--mark-as-output, eshell--mark-yanked-as-output): New
functions, mostly copied from comint.

* lisp/eshell/esh-proc.el (eshell-interactive-process-filter):
* lisp/eshell/esh-mode.el (eshell-interactive-print): Call
'eshell--mark-as-output'.
(eshell-get-old-input): Remove properties from the returned string
just to be safe.

* test/lisp/eshell/eshell-tests.el (eshell-test-value): New variable.
(eshell-test/get-old-input/rerun-command)
(eshell-test/get-old-input/run-output): New tests.

* test/lisp/eshell/em-prompt-tests.el
(em-prompt-test/field-properties)
(em-prompt-test/field-properties/no-highlight): Use
'eshell-command-output-properties'.

1 files changed, 28 insertions, 0 deletions

diff --git a/test/lisp/eshell/eshell-tests.el b/test/lisp/eshell/eshell-tests.el
index 776cfb9b92f..743cc28b9b5 100644
--- a/test/lisp/eshell/eshell-tests.el
+++ b/test/lisp/eshell/eshell-tests.el
@@ -34,6 +34,8 @@
                            (file-name-directory (or load-file-name
                                                     default-directory))))
 
+(defvar eshell-test-value nil)
+
 ;;; Tests:
 
 (ert-deftest eshell-test/pipe-headproc ()
@@ -160,6 +162,32 @@ insert the queued one at the next prompt, and finally run it."
      (beginning-of-line))
    (should (string= (eshell-get-old-input) "echo alpha"))))
 
+(ert-deftest eshell-test/get-old-input/rerun-command ()
+  "Test that we can rerun an old command when point is on it."
+  (with-temp-eshell
+   (let ((eshell-test-value "first"))
+     (eshell-match-command-output "echo $eshell-test-value" "first"))
+   ;; Go to the previous prompt.
+   (forward-line -2)
+   (let ((inhibit-field-text-motion t))
+     (end-of-line))
+   ;; Rerun the command, but with a different variable value.
+   (let ((eshell-test-value "second"))
+     (eshell-send-input))
+   (eshell-match-output "second")))
+
+(ert-deftest eshell-test/get-old-input/run-output ()
+  "Test that we can run a line of output as a command when point is on it."
+  (with-temp-eshell
+   (eshell-match-command-output "echo \"echo there\"" "echo there")
+   ;; Go to the output, and insert "hello" after "echo".
+   (forward-line -1)
+   (forward-word)
+   (insert " hello")
+   ;; Run the line as a command.
+   (eshell-send-input)
+   (eshell-match-output "(\"hello\" \"there\")")))
+
 (provide 'eshell-tests)
 
 ;;; eshell-tests.el ends here