Accept alists when serializing JSON

* src/json.c (lisp_to_json_toplevel_1): Also accept alists
representing objects.

* src/json.c (Fjson_serialize): Update docstring.

* test/src/json-tests.el (json-serialize/object): Add unit tests for
serializing alists.

* doc/lispref/text.texi (Parsing JSON): Document that serialization
functions accept alists.

1 files changed, 13 insertions, 1 deletions

diff --git a/test/src/json-tests.el b/test/src/json-tests.el
index 5d9f6b3840c..b23439a59fd 100644
--- a/test/src/json-tests.el
+++ b/test/src/json-tests.el
@@ -50,7 +50,19 @@
     (puthash "abc" [1 2 t] table)
     (puthash "def" :null table)
     (should (equal (json-serialize table)
-                   "{\"abc\":[1,2,true],\"def\":null}"))))
+                   "{\"abc\":[1,2,true],\"def\":null}")))
+  (should (equal (json-serialize '((abc . [1 2 t]) (def . :null)))
+                 "{\"abc\":[1,2,true],\"def\":null}"))
+  (should (equal (json-serialize nil) "{}"))
+  (should (equal (json-serialize '((abc))) "{\"abc\":{}}"))
+  (should (equal (json-serialize '((a . 1) (b . 2) (a . 3)))
+                 "{\"a\":1,\"b\":2}"))
+  (should-error (json-serialize '(abc)) :type 'wrong-type-argument)
+  (should-error (json-serialize '((a 1))) :type 'wrong-type-argument)
+  (should-error (json-serialize '((1 . 2))) :type 'wrong-type-argument)
+  (should-error (json-serialize '((a . 1) . b)) :type 'wrong-type-argument)
+  (should-error (json-serialize '#1=((a . 1) . #1#)) :type 'circular-list)
+  (should-error (json-serialize '(#1=(a #1#)))))
 
 (ert-deftest json-serialize/object-with-duplicate-keys ()
   (skip-unless (fboundp 'json-serialize))