master fa9197fcb09: Specialize default-get for alist widgets (Bug#63290)

[Eli Zaretskii]

branch: master
commit fa9197fcb097ad0847c5955ac5ad50ca47826fe1
Author: Mauro Aranda <maurooaranda@gmail.com>
Commit: Eli Zaretskii <eliz@gnu.org>

    Specialize default-get for alist widgets (Bug#63290)
    
    * lisp/wid-edit.el (widget-list-default-get)
    (widget-alist-default-get): New functions.
    (list, alist): Use it.
    * test/lisp/cus-edit-tests.el (cus-edit-test-bug63290-option)
    (cus-edit-test-bug63290-option-2): New test options.
    (cus-edit-test-bug63290): New test.
    * test/lisp/wid-edit-tests.el (widget-test-alist-default-value-1)
    (widget-test-alist-default-value-2)
    (widget-test-alist-default-value-3)
    (widget-test-alist-default-value-4): New tests.
---
 lisp/wid-edit.el            | 32 +++++++++++++++++++++++++++++++-
 test/lisp/cus-edit-tests.el | 43 +++++++++++++++++++++++++++++++++++++++++++
 test/lisp/wid-edit-tests.el | 31 +++++++++++++++++++++++++++++++
 3 files changed, 105 insertions(+), 1 deletion(-)

diff --git a/lisp/wid-edit.el b/lisp/wid-edit.el
index fabf590f6b8..a70598bb6c9 100644
--- a/lisp/wid-edit.el
+++ b/lisp/wid-edit.el
@@ -3801,8 +3801,19 @@ like the newline character or the tab character."
 (define-widget 'list 'group
   "A Lisp list."
   :tag "List"
+  :default-get #'widget-list-default-get
   :format "%{%t%}:\n%v")
 
+(defun widget-list-default-get (widget)
+  "Return the default external value for a list WIDGET.
+
+The default value is the one stored in the :value property, even if it is nil,
+or a list with the default value of each component of the list WIDGET."
+  (widget-apply widget :value-to-external
+                (if (widget-member widget :value)
+                    (widget-get widget :value)
+                  (widget-group-default-get widget))))
+
 (define-widget 'vector 'group
   "A Lisp vector."
   :tag "Vector"
@@ -3931,7 +3942,6 @@ example:
            value-type widget-plist-value-type))
     `(group :format "Key: %v" :inline t ,key-type ,value-type)))
 
-
 ;;; The `alist' Widget.
 ;;
 ;; Association lists.
@@ -3941,6 +3951,7 @@ example:
   :key-type '(sexp :tag "Key")
   :value-type '(sexp :tag "Value")
   :convert-widget 'widget-alist-convert-widget
+  :default-get #'widget-alist-default-get
   :tag "Alist")
 
 (defvar widget-alist-value-type)       ;Dynamic variable
@@ -3975,6 +3986,25 @@ example:
       (setq key-type `(const ,option)
            value-type widget-alist-value-type))
     `(cons :format "Key: %v" ,key-type ,value-type)))
+
+(defun widget-alist-default-get (widget)
+  "Return the default value for WIDGET, an alist widget.
+
+The default value may be one of:
+- The one stored in the :value property, even if it is nil.
+- If WIDGET has options available, an alist consisting of the
+default values for each option.
+- nil, otherwise."
+  (widget-apply widget :value-to-external
+                (cond ((widget-member widget :value)
+                       (widget-get widget :value))
+                      ((widget-get widget :options)
+                       (mapcar #'widget-default-get
+                               ;; Last one is the editable-list part, and
+                               ;; we don't want those showing up as
+                               ;; part of the default value.  (Bug#63290)
+                               (butlast (widget-get widget :args))))
+                      (t nil))))
 
 (define-widget 'choice 'menu-choice
   "A union of several sexp types.
diff --git a/test/lisp/cus-edit-tests.el b/test/lisp/cus-edit-tests.el
index eca35d7c96a..3a788f19745 100644
--- a/test/lisp/cus-edit-tests.el
+++ b/test/lisp/cus-edit-tests.el
@@ -92,5 +92,48 @@
             (buffer-substring-no-properties (point-min) (point-max)))))
     (should (string-search "Value `:foo' does not match type number"
                            warn-txt))))
+
+(defcustom cus-edit-test-bug63290-option nil
+  "Choice option for testing Bug#63290."
+  :type '(choice (alist
+                  :key-type (string :tag "key")
+                  :value-type (string :tag "value"))
+                 (const :tag "auto" auto)))
+
+(defcustom cus-edit-test-bug63290-option2 'some
+  "Choice option for testing Bug#63290."
+  :type '(choice
+          (const :tag "some" some)
+          (alist
+           :key-type (string :tag "key")
+           :value-type (string :tag "value"))))
+
+(ert-deftest cus-edit-test-bug63290 ()
+  "Test that changing a choice value back to an alist respects its nil value."
+  (customize-variable 'cus-edit-test-bug63290-option)
+  (search-forward "Value")
+  ;; Simulate changing the value.
+  (let* ((choice (widget-at))
+         (args (widget-get choice :args))
+         (list-opt (car (widget-get choice :children)))
+         (const-opt (nth 1 args)))
+    (widget-put choice :explicit-choice const-opt)
+    (widget-value-set choice (widget-default-get const-opt))
+    (widget-put choice :explicit-choice list-opt)
+    (widget-value-set choice (widget-default-get list-opt)))
+  ;; No empty key/value pairs should show up.
+  (should-not (search-forward "key" nil t))
+  (customize-variable 'cus-edit-test-bug63290-option2)
+  (search-forward "Value")
+  ;; Simulate changing the value.
+  (let* ((choice (widget-at))
+         (args (widget-get choice :args))
+         (const-opt (car (widget-get choice :children)))
+         (list-opt (nth 1 args)))
+    (widget-put choice :explicit-choice list-opt)
+    (widget-value-set choice (widget-default-get list-opt)))
+  ;; No empty key/value pairs should show up.
+  (should-not (search-forward "key" nil t)))
+
 (provide 'cus-edit-tests)
 ;;; cus-edit-tests.el ends here
diff --git a/test/lisp/wid-edit-tests.el b/test/lisp/wid-edit-tests.el
index b379c7c91a8..ebfe729bc9a 100644
--- a/test/lisp/wid-edit-tests.el
+++ b/test/lisp/wid-edit-tests.el
@@ -349,4 +349,35 @@ return nil, even with a non-nil bubblep argument."
     (should-not (widget-apply widget :match "someundefinedcolorihope"))
     (should-not (widget-apply widget :match "#11223"))))
 
+(ert-deftest widget-test-alist-default-value-1 ()
+  "Test getting the default value for an alist widget with options."
+  (with-temp-buffer
+    (let ((w (widget-create '(alist :key-type string
+                                    :value-type integer
+                                    :options (("0" (integer)))))))
+      (should (equal '(("0" . 0)) (widget-default-get w))))))
+
+(ert-deftest widget-test-alist-default-value-2 ()
+  "Test getting the default value for an alist widget without :value."
+  (with-temp-buffer
+    (let ((w (widget-create '(alist :key-type string
+                                    :value-type integer))))
+      (should-not (widget-default-get w)))))
+
+(ert-deftest widget-test-alist-default-value-3 ()
+  "Test getting the default value for an alist widget with nil :value."
+  (with-temp-buffer
+    (let ((w (widget-create '(alist :key-type string
+                                    :value-type integer
+                                    :value nil))))
+      (should-not (widget-default-get w)))))
+
+(ert-deftest widget-test-alist-default-value-4 ()
+  "Test getting the default value for an alist widget with non-nil :value."
+  (with-temp-buffer
+    (let ((w (widget-create '(alist :key-type string
+                                    :value-type integer
+                                    :value (("1" . 1) ("2" . 2))))))
+      (should (equal '(("1" . 1) ("2" . 2)) (widget-default-get w))))))
+
 ;;; wid-edit-tests.el ends here