Emacs/Guix: Wait for process termination when install profiles.

.emacs.d/lisp/init-guix.el

@@ -128,19 +128,34 @@ If MANIFEST is nil, it is queried from the manifests found in `ambrevar/guix-man
 
 (defun ambrevar/run-in-eshell (command)
   (let ((eshell-buffer-name "*guix*"))
-      (eshell)
-      (when (eshell-interactive-process)
-        (eshell t))
+    (eshell)
+    (when (eshell-interactive-process)
+      (eshell t))
+    (if (get-buffer-process (current-buffer))
+        (message "Try again after current process termination.")
       (eshell-interrupt-process)
       (insert command)
-      (eshell-send-input)))
+      (eshell-send-input))))
 
 (defun ambrevar/run-in-shell (command)
-  (shell (generate-new-buffer (generate-new-buffer-name "*guix*")))
-  (goto-char (point-max))
-  (comint-delete-input)
-  (insert command)
-  (comint-send-input))
+  (shell (get-buffer-create "*guix*"))
+  (let ((process (get-buffer-process (current-buffer))))
+    (when process
+      (accept-process-output process 0.1)))
+  (if (ambrevar/helm-ff-shell-alive-p)
+      (message "Try again after current process termination.")
+    (goto-char (point-max))
+    (comint-delete-input)
+    (insert command)
+    (comint-send-input)))
+
+(defun ambrevar/helm-ff-shell-alive-p ()         ; TODO: Use function from Helm 3.6.3 once out.
+   "Returns non nil when a process is running inside `shell-mode' buffer."
+   (save-excursion
+     (comint-goto-process-mark)
+     (or (null comint-last-prompt)
+         (not (eql (point)
+                   (marker-position (cdr comint-last-prompt)))))))
 
 (defun ambrevar/guix-install-manifest (&optional manifest channel)
   "Install Guix manifest to `ambrevar/guix-extra-profiles'.

.emacs.d/lisp/init-shell.el

@@ -35,10 +35,10 @@ prefix arg shell buffer doesn't exists, create it and switch to it."
                      (car bufs)))
         (switch-to-buffer it)
       (shell))
-    ;; TODO: Can we check if a process is currently running within the running shell?
     (funcall cd-shell)))
 
 (advice-add 'helm-ff-switch-to-eshell :override 'ambrevar/helm-ff-switch-to-shell)
+;; TODO: Above code can be removed with Helm 3.6.3.
 
 (defun ambrevar/shell-setup ()
   (set (make-variable-buffer-local 'comint-input-history-ignore)