shell layer: Add option to protect the Eshell prompt

contrib/shell/README.org

@@ -10,6 +10,7 @@
      - [[#default-shell-position-and-height][Default shell position and height]]
      - [[#set-shell-for-term-and-ansi-term][Set shell for term and ansi-term]]
      - [[#enable-em-smart-in-eshell][Enable em-smart in Eshell]]
+     - [[#protect-your-eshell-prompt][Protect your Eshell prompt]]
  - [[#eshell][Eshell]]
  - [[#key-bindings][Key bindings]]
      - [[#multi-term][Multi-term]]
@@ -104,6 +105,22 @@ To enable =em-smart= put the following layer variable to non-nil:
     '(shell :variables shell-enable-smart-eshell t))
 #+END_SRC
 
+** Protect your Eshell prompt
+
+Comint mode (Shell mode) has good support for Evil mode as it inhibits movement
+commands over the prompt. This has the added benefit that Evil mode functions
+work sensibly. E.g. you can press ~cc~ in normal state i.e.
+=evil-change-whole-line= to kill the current input and start typing a new
+command. In Eshell you also kill the prompt, which is often unintended.
+
+To enable a the same behavior as in Comint mode you can enable the following
+variable:
+
+#+BEGIN_SRC emacs-lisp
+  (setq-default dotspacemacs-configuration-layers
+    '(shell :variables shell-protect-eshell-prompt t))
+#+END_SRC
+
 * Eshell
 
 Some advanced configuration is setup for =eshell= in this layer:

contrib/shell/config.el

@@ -32,3 +32,8 @@
 (defvar shell-enable-smart-eshell nil
   "If non-nil then `em-smart' is enabled. `em-smart' allows to quickly review
 commands, modify old commands or enter a new one.")
+
+(defvar shell-protect-eshell-prompt nil
+  "If non-nil then eshell's prompt is protected. This means that
+  that movement to the prompt is inhibited like for `comint-mode'
+  prompts and the prompt is made read-only")

contrib/shell/packages.el

@@ -69,6 +69,23 @@ the user activate the completion manually."
                    (not (eq (line-end-position) (point-max))))
           (end-of-buffer)))
 
+      (when shell-protect-eshell-prompt
+        (defun protect-eshell-prompt ()
+          "Protect Eshell's prompt like Comint's prompts.
+
+E.g. `evil-change-whole-line' won't wipe the prompt. This
+is achieved by adding the relevant text properties."
+          (let ((inhibit-field-text-motion t))
+            (add-text-properties
+             (point-at-bol)
+             (point)
+             '(rear-nonsticky t
+               inhibit-line-move-field-capture t
+               field output
+               read-only t
+               front-sticky (field inhibit-line-move-field-capture)))))
+        (add-hook 'eshell-after-prompt-hook 'protect-eshell-prompt))
+
       (defun spacemacs//init-eshell ()
         "Stuff to do when enabling eshell."
         (setq pcomplete-cycle-completions nil)