core: new package keyword :toggle

This new keyword allows to add all the packages to the <layer>-packages
even when a package is not toggled on by a given layer variable.

This fixes an issue of the layer system where we had to choose between
discoverability (ie. the list of package in helm or ivy with SPC h SPC)
and installation of package (because any package listed in the variable
<layer>-packages were installed).

CHANGELOG.next

@@ -316,8 +316,11 @@ This file containes the change log for the next major version of Spacemacs.
   =packages-funcs.el= files
 - New functions =configuration-layer/remove-layer= and
   =configuration-layer/remove-layers=.
-- New package location =site=, a site package is a package installed on the
-  host by a third party (ie. =mu4e= which is installed by =mu=)
+- New package keyword =:toggle= which can be a symbol or a list. A package is
+  considered to be used if the toggle evaluates to non nil. By default =:toggle=
+  is =t=.
+- New value =site= for package =:location= keyword, a site package is a package
+  installed on the host by a third party (ie. =mu4e= which is installed by =mu=)
 - Improve =spacemacs|diminish= function (thanks to TheBB)
 *** Other fixes and improvements
 - Typos and documentation improvements (thanks to adrsta, andreas-h,

core/core-configuration-layer.el

@@ -92,11 +92,11 @@
    (pre-layers :initarg :pre-layers
                :initform '()
                :type list
-               :documentation "Layers with a pre-init function.")
+               :documentation "List of layers with a pre-init function.")
    (post-layers :initarg :post-layers
                :initform '()
                :type list
-               :documentation "Layers with a post-init function.")
+               :documentation "List of layers with a post-init function.")
    (location :initarg :location
              :initform elpa
              :type (satisfies (lambda (x)
@@ -104,6 +104,11 @@
                                     (member x '(built-in local site elpa))
                                     (and (listp x) (eq 'recipe (car x))))))
              :documentation "Location of the package.")
+   (toggle :initarg :toggle
+           :initform t
+           :type (satisfies (lambda (x) (or (symbolp x) (listp x))))
+           :documentation
+           "Package is enabled/installed if toggle evaluates to non-nil.")
    (step :initarg :step
          :initform nil
          :type (satisfies (lambda (x) (member x '(nil pre))))
@@ -124,6 +129,13 @@
              :documentation
              "If non-nil this package is excluded from all layers.")))
 
+(defmethod cfgl-package-enabledp ((pkg cfgl-package))
+  "Evaluate the `toggle' slot of passed PKG."
+  (let ((toggle (oref pkg :toggle)))
+    (cond
+     ((symbolp toggle) (symbol-value toggle))
+     ((listp toggle) (eval toggle)))))
+
 (defvar configuration-layer--elpa-archives
   '(("melpa" . "melpa.org/packages/")
     ("org"   . "orgmode.org/elpa/")
@@ -465,6 +477,7 @@ Properties that can be copied are `:location', `:step' and `:excluded'."
    packages (lambda (x) (and (not (null (oref x :owner)))
                              (not (memq (oref x :location) '(built-in site local)))
                              (not (stringp (oref x :location)))
+                             (cfgl-package-enabledp x)
                              (not (oref x :excluded))))))
 
 (defun configuration-layer//get-private-layer-dir (name)
@@ -889,6 +902,8 @@ Returns non-nil if the packages have been installed."
        ((null (oref pkg :owner))
         (spacemacs-buffer/message
          (format "%S ignored since it has no owner layer." pkg-name)))
+       ((not (cfgl-package-enabledp pkg))
+        (spacemacs-buffer/message (format "%S is toggled off." pkg-name)))
        (t
         ;; load-path
         (let ((location (oref pkg :location)))

tests/core/core-configuration-layer-utest.el

@@ -11,6 +11,38 @@
 (require 'mocker)
 (require 'core-configuration-layer)
 
+;; ---------------------------------------------------------------------------
+;; class cfgl-package
+;; ---------------------------------------------------------------------------
+
+(ert-deftest test-cfgl-package-enabledp--default-toggle-eval-non-nil ()
+  (let ((pkg (cfgl-package "testpkg" :name 'testpkg)))
+    (should (cfgl-package-enabledp pkg))))
+
+(ert-deftest test-cfgl-package-enabledp--symbol-toggle-eval-non-nil-example ()
+  (let ((pkg (cfgl-package "testpkg" :name 'testpkg :toggle 'package-toggle))
+        (package-toggle t))
+    (should (cfgl-package-enabledp pkg))))
+
+(ert-deftest test-cfgl-package-enabledp--symbol-toggle-eval-nil-example ()
+  (let ((pkg (cfgl-package "testpkg" :name 'testpkg :toggle 'package-toggle))
+        (package-toggle nil))
+    (should (null (cfgl-package-enabledp pkg)))))
+
+(ert-deftest test-cfgl-package-enabledp--list-toggle-eval-non-nil-example ()
+  (let ((pkg (cfgl-package "testpkg"
+                           :name 'testpkg
+                           :toggle '(memq package-toggle '(foo bar))))
+        (package-toggle 'foo))
+    (should (cfgl-package-enabledp pkg))))
+
+(ert-deftest test-cfgl-package-enabledp--list-toggle-eval-nil-example ()
+  (let ((pkg (cfgl-package "testpkg"
+                           :name 'testpkg
+                           :toggle '(memq package-toggle '(foo bar))))
+        (package-toggle 'other))
+    (should (null (cfgl-package-enabledp pkg)))))
+
 ;; ---------------------------------------------------------------------------
 ;; configuration-layer//resolve-package-archives
 ;; ---------------------------------------------------------------------------
@@ -501,7 +533,7 @@
       (layer1/init-pkg nil ((:output nil :occur 1))))
      (configuration-layer//configure-package pkg))))
 
-(ert-deftest test-configure-packages--pre-init-is-evaluated ()
+(ert-deftest test-configure-package--pre-init-is-evaluated ()
   (let ((pkg (cfgl-package "pkg" :name 'pkg :owner 'layer1 :pre-layers '(layer2)))
         (configuration-layer--layers
          `(,(cfgl-layer "layer1" :name 'layer1)
@@ -593,6 +625,23 @@
       (spacemacs-buffer/loading-animation nil ((:output nil))))
      (configuration-layer//configure-packages-2 `(,pkg)))))
 
+(ert-deftest test-configure-packages-2--toggle-t-is-configured ()
+  (let ((pkg (cfgl-package "pkg" :name 'pkg :owner 'layer1 :toggle t))
+        (mocker-mock-default-record-cls 'mocker-stub-record))
+    (mocker-let
+     ((configuration-layer//configure-package (p) ((:occur 1)))
+      (spacemacs-buffer/loading-animation nil ((:output nil))))
+     (configuration-layer//configure-packages-2 `(,pkg)))))
+
+(ert-deftest test-configure-packages-2--toggle-nil-is-not-configured ()
+  (let ((pkg (cfgl-package "pkg" :name 'pkg :owner 'layer1 :toggle nil))
+        (mocker-mock-default-record-cls 'mocker-stub-record))
+    (mocker-let
+     ((configuration-layer//configure-package (p) nil)
+      (spacemacs-buffer/loading-animation nil ((:output nil)))
+      (spacemacs-buffer/message (m) ((:output nil))))
+     (configuration-layer//configure-packages-2 `(,pkg)))))
+
 (ert-deftest test-configure-packages-2--protected-package-is-configured()
   (let ((pkg (cfgl-package "pkg" :name 'pkg :owner 'layer1 :protected t))
         (mocker-mock-default-record-cls 'mocker-stub-record))