Do not colorize a deleted buffer

Users should be able to manually kill the
*quickrun* buffer with no errors.

* quickrun.el (quickrun--make-sentinel):
Check if quickrun--buffer-name still alive before
call quickrun--apply-colorizing.
* test/test-quickrun.el (quickrun:user-manually-terminates-program):
Add test.
* sample/sample_endless_loop.bash:
Add sample file for the new test.

quickrun.el

@@ -1023,7 +1023,8 @@ if you set your own language configuration.")
                (quickrun--exec rest-commands input orig-mode))
               (t
                (if (not is-success)
-                   (if (eq quickrun-option-outputter #'quickrun--default-outputter)
+                   (if (and (buffer-live-p quickrun--buffer-name)
+                            (eq quickrun-option-outputter #'quickrun--default-outputter))
                        (quickrun--apply-colorizing input orig-mode)
                      (message "Failed: Exit Status=%d" exit-status))
                  (quickrun--apply-outputter outputter-func)

sample/sample_endless_loop.bash

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+function endlessLoop () {
+    local step=1
+    while true
+    do
+        printf "Endless loop step %d\n" $step
+        ((step+=1))
+        sleep 1
+    done
+}
+
+endlessLoop

test/test-quickrun.el

@@ -77,4 +77,19 @@
          (use-tempfile (quickrun--use-tempfile-p "hoge")))
     (should-not use-tempfile)))
 
+(ert-deftest quickrun:user-manually-terminates-program ()
+  "Users are able to manually terminate the program with no errors."
+  (with-current-buffer (find-file-noselect "sample/sample_endless_loop.bash")
+    (quickrun))
+  (sleep-for 1)
+  (condition-case err
+      (let ((buf (get-buffer "*quickrun*"))
+            (inhibit-message t))
+        (set-process-query-on-exit-flag (get-buffer-process buf) nil)
+        (kill-buffer buf)
+	    (sleep-for 1)) ; Wait for the sentinel.
+    (wrong-type-argument
+     (quickrun--remove-temp-files)
+     (signal 'error "Cannot access a deleted buffer"))))
+
 ;;; test-quickrun.el ends here