core: hide home buffer if a file is passed on the command line

Note that any non Emacsy command line parameter and non processed
command line parameter (that is unknown from Spacemacs) will hide the
home buffer. This should be good enough.

Fixes #4057

core/core-command-line.el

@@ -10,9 +10,10 @@
 ;;
 ;;; License: GPLv3
 
-;; process args
 (defun spacemacs//parse-command-line (args)
-  "Process ARGS relevant to core-debug.el"
+  "Handle Spacemacs specific command line arguments.
+The reason why we don't use the Emacs hooks for processing user defined
+arguments is that we want to process these arguments as soon as possible."
   (let ((i 0) new-args)
     (while (< i (length args))
       (let ((arg (nth i args))
@@ -43,4 +44,13 @@
 
 (setq command-line-args (spacemacs//parse-command-line command-line-args))
 
+(defun spacemacs//hide-home-buffer ()
+  "Hides the Spacemacs home buffer at startup to not obfuscate the opened
+startup file.
+Note that any non Emacsy command line parameter will have the effect to
+hide the home buffer."
+  (setq initial-buffer-choice nil))
+
+(push 'spacemacs//hide-home-buffer command-line-functions)
+
 (provide 'core-command-line)

core/core-spacemacs.el

@@ -86,6 +86,7 @@
      (spacemacs-buffer/warning "Cannot find font \"%s\"!"
                                (car dotspacemacs-default-font))))
   ;; spacemacs init
+  (setq inhibit-startup-screen t)
   (spacemacs-buffer/goto-buffer)
   (unless (display-graphic-p)
     ;; explicitly recreate the home buffer for the first GUI client