core: new variable dotspacemacs-ask-for-lazy-installation

core/core-configuration-layer.el

@@ -993,11 +993,11 @@ path."
 
 (defun configuration-layer//lazy-install-packages (layer-name mode)
   "Install layer with LAYER-NAME to support MODE."
-  (when (and (configuration-layer//lazy-install-p layer-name)
-             (yes-or-no-p (format
-                           (concat "Support for %s requires installation of "
-                                   "layer %s, do you want to install it?")
-                           mode layer-name)))
+  (when (or (not dotspacemacs-ask-for-lazy-installation)
+            (yes-or-no-p (format
+                          (concat "Support for %s requires installation of "
+                                  "layer %s, do you want to install it?")
+                          mode layer-name)))
     (when (dotspacemacs/add-layer layer-name)
       (configuration-layer/sync 'no-install))
     (let* ((layer (object-assoc layer-name :name configuration-layer--layers))

core/core-dotspacemacs.el

@@ -75,6 +75,10 @@ that support lazy installation even the layers listed in
 and you have to explicitly list a layer in the variable
 `dotspacemacs-configuration-layers' to install it.")
 
+(defvar dotspacemacs-ask-for-lazy-installation t
+  "If non-nil then Spacemacs will ask for confirmation before installing
+a layer lazily.")
+
 (defvar dotspacemacs-additional-packages '()
   "List of additional packages that will be installed wihout being
 wrapped in a layer. If you need some configuration for these

core/templates/.spacemacs.template

@@ -21,9 +21,10 @@ values."
    ;; variable `dotspacemacs-configuration-layers' to install it.
    ;; (default 'unused)
    dotspacemacs-enable-lazy-installation 'unused
+   ;; If non-nil then Spacemacs will ask for confirmation before installing
+   ;; a layer lazily. (default t)
+   dotspacemacs-ask-for-lazy-installation t
    ;; If non-nil layers with lazy install support are lazy installed.
-   ;; (default t)
-   dotspacemacs-enable-lazy-installation t
    ;; List of additional paths where to look for configuration layers.
    ;; Paths must have a trailing slash (i.e. `~/.mycontribs/')
    dotspacemacs-configuration-layer-path '()