bug#24252: 25.1; json.el doesn't distinguish null and empty object

[Yoichi Nakayama <yoichi.nakayama@gmail.com>]

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Fixed tests and update object encoding functions to be functional without
binding json-object-type as far as possible.
;; You can find a series of patches at
https://github.com/yoichi/emacs/tree/fix/json-empty-object2

From d8549a88633704fc76eb6cdafa6b6ea591fb14e3 Mon Sep 17 00:00:00 2001
From: Yoichi Nakayama <yoichi.nakayama@gmail.com>
Date: Sun, 21 Aug 2016 23:54:43 +0900
Subject: [PATCH] Bind json-object-type on object encoding functions

If elisp object are plist or hash-table, assume they are created with
associated json-object-type.

* json.el (json--plist-to-alist): Convert key format.
(json-encode-hash-table, json-encode-alist, json-encode-plist): Bind
json-object-type.
* json-tests.el (test-json-plist-to-alist): Use default key type for
expected value, and add test with json-key-type.
(test-json-encode-key): Add test not to confuse internal symbols.
(test-json-encode-hash-table, test-json-encode-alist-with-sort-predicate,
test-json-encode-list): Use default key type.
---
 lisp/json.el            | 134
++++++++++++++++++++++++++----------------------
 test/lisp/json-tests.el |  29 +++++++----
 2 files changed, 91 insertions(+), 72 deletions(-)

diff --git a/lisp/json.el b/lisp/json.el
index a387b08..24fefc5 100644
--- a/lisp/json.el
+++ b/lisp/json.el
@@ -174,6 +174,10 @@ Unlike `reverse', this keeps the property-value pairs
intact."
     (while plist
       (let ((prop (pop plist))
             (val (pop plist)))
+        (when (and (not json-key-type)
+                   (keywordp prop))
+          (setq prop (intern
+                      (substring (symbol-name prop) 1))))
         (push (cons prop val) res)))
     (nreverse res)))

@@ -526,79 +530,85 @@ Please see the documentation of `json-object-type'
and `json-key-type'."

 (defun json-encode-hash-table (hash-table)
   "Return a JSON representation of HASH-TABLE."
-  (if json-encoding-object-sort-predicate
-      (json-encode-alist (map-into hash-table 'list))
+  (let ((json-object-type 'hash-table))
+    (if json-encoding-object-sort-predicate
+        (let ((json-key-type
+               (or json-key-type
+                   'string)))
+          (json-encode-alist (map-into hash-table 'list)))
+      (format "{%s%s}"
+              (json-join
+               (let (r)
+                 (json--with-indentation
+                  (maphash
+                   (lambda (k v)
+                     (push (format
+                            (if json-encoding-pretty-print
+                                "%s%s: %s"
+                              "%s%s:%s")
+                            json--encoding-current-indentation
+                            (json-encode-key k)
+                            (json-encode v))
+                           r))
+                   hash-table))
+                 r)
+               json-encoding-separator)
+              (if (or (not json-encoding-pretty-print)
+                      json-encoding-lisp-style-closings)
+                  ""
+                json--encoding-current-indentation)))))
+
+;; List encoding (including alists and plists)
+
+(defun json-encode-alist (alist)
+  "Return a JSON representation of ALIST."
+  (let ((json-object-type 'alist))
+    (when json-encoding-object-sort-predicate
+      (setq alist
+            (sort alist (lambda (a b)
+                          (funcall json-encoding-object-sort-predicate
+                                   (car a) (car b))))))
     (format "{%s%s}"
             (json-join
-             (let (r)
-               (json--with-indentation
-                (maphash
-                 (lambda (k v)
-                   (push (format
-                          (if json-encoding-pretty-print
-                              "%s%s: %s"
-                            "%s%s:%s")
-                          json--encoding-current-indentation
-                          (json-encode-key k)
-                          (json-encode v))
-                         r))
-                 hash-table))
-               r)
+             (json--with-indentation
+              (mapcar (lambda (cons)
+                        (format (if json-encoding-pretty-print
+                                    "%s%s: %s"
+                                  "%s%s:%s")
+                                json--encoding-current-indentation
+                                (json-encode-key (car cons))
+                                (json-encode (cdr cons))))
+                      alist))
              json-encoding-separator)
             (if (or (not json-encoding-pretty-print)
                     json-encoding-lisp-style-closings)
                 ""
               json--encoding-current-indentation))))

-;; List encoding (including alists and plists)
-
-(defun json-encode-alist (alist)
-  "Return a JSON representation of ALIST."
-  (when json-encoding-object-sort-predicate
-    (setq alist
-          (sort alist (lambda (a b)
-                        (funcall json-encoding-object-sort-predicate
-                                 (car a) (car b))))))
-  (format "{%s%s}"
-          (json-join
-           (json--with-indentation
-            (mapcar (lambda (cons)
-                      (format (if json-encoding-pretty-print
-                                  "%s%s: %s"
-                                "%s%s:%s")
-                              json--encoding-current-indentation
-                              (json-encode-key (car cons))
-                              (json-encode (cdr cons))))
-                    alist))
-           json-encoding-separator)
-          (if (or (not json-encoding-pretty-print)
-                  json-encoding-lisp-style-closings)
-              ""
-            json--encoding-current-indentation)))
-
 (defun json-encode-plist (plist)
   "Return a JSON representation of PLIST."
-  (if json-encoding-object-sort-predicate
-      (json-encode-alist (json--plist-to-alist plist))
-    (let (result)
-      (json--with-indentation
-       (while plist
-         (push (concat
-                json--encoding-current-indentation
-                (json-encode-key (car plist))
-                (if json-encoding-pretty-print
-                    ": "
-                  ":")
-                (json-encode (cadr plist)))
-               result)
-         (setq plist (cddr plist))))
-      (concat "{"
-              (json-join (nreverse result) json-encoding-separator)
-              (if (and json-encoding-pretty-print
-                       (not json-encoding-lisp-style-closings))
+  (let ((json-object-type 'plist))
+    (if json-encoding-object-sort-predicate
+        (json-encode-alist (json--plist-to-alist plist))
+      (let (result)
+        (json--with-indentation
+         (while plist
+           (push (concat
                   json--encoding-current-indentation
-                "")
-              "}"))))
+                  (json-encode-key (car plist))
+                  (if json-encoding-pretty-print
+                      ": "
+                    ":")
+                  (json-encode (cadr plist)))
+                 result)
+           (setq plist (cddr plist))))
+        (concat "{"
+                (json-join (nreverse result) json-encoding-separator)
+                (if (and json-encoding-pretty-print
+                         (not json-encoding-lisp-style-closings))
+                    json--encoding-current-indentation
+                  "")
+                "}")))))

 (defun json-encode-list (list)
   "Return a JSON representation of LIST.
diff --git a/test/lisp/json-tests.el b/test/lisp/json-tests.el
index 78cebb4..d5abb58 100644
--- a/test/lisp/json-tests.el
+++ b/test/lisp/json-tests.el
@@ -62,9 +62,11 @@ Point is moved to beginning of the buffer."

 (ert-deftest test-json-plist-to-alist ()
   (should (equal (json--plist-to-alist '()) '()))
-  (should (equal (json--plist-to-alist '(:a 1)) '((:a . 1))))
+  (should (equal (json--plist-to-alist '(:a 1)) '((a . 1))))
+  (let ((json-key-type 'keyword))
+    (should (equal (json--plist-to-alist '(:a 1)) '((:a . 1)))))
   (should (equal (json--plist-to-alist '(:a 1 :b 2 :c 3))
-                 '((:a . 1) (:b . 2) (:c . 3)))))
+                 '((a . 1) (b . 2) (c . 3)))))

 (ert-deftest test-json-advance ()
   (json-tests--with-temp-buffer "{ \"a\": 1 }"
@@ -177,9 +179,16 @@ Point is moved to beginning of the buffer."
                  "\"\\nasdфыв\\u001f\u007ffgh\\t\"")))

 (ert-deftest test-json-encode-key ()
-  (should (equal (json-encode-key "foo") "\"foo\""))
-  (should (equal (json-encode-key 'foo) "\"foo\""))
-  (should (equal (json-encode-key :foo) "\"foo\""))
+  (let ((json-key-type 'string))
+    (should (equal (json-encode-key "foo") "\"foo\""))
+    (should-error (json-encode-key t) :type 'json-key-format))
+  (let ((json-key-type 'symbol))
+    (should (equal (json-encode-key 'foo) "\"foo\""))
+    (should (equal (json-encode-key t) "\"t\""))
+    (should (equal (json-encode-key :t) "\":t\"")))
+  (let ((json-key-type 'keyword))
+    (should (equal (json-encode-key :foo) "\"foo\""))
+    (should-error (json-encode-key t) :type 'json-key-format))
   (should-error (json-encode-key 5) :type 'json-key-format)
   (should-error (json-encode-key ["foo"]) :type 'json-key-format)
   (should-error (json-encode-key '("foo")) :type 'json-key-format))
@@ -238,9 +247,9 @@ Point is moved to beginning of the buffer."
   (let ((hash-table (make-hash-table))
         (json-encoding-object-sort-predicate 'string<)
         (json-encoding-pretty-print nil))
-    (puthash :a 1 hash-table)
-    (puthash :b 2 hash-table)
-    (puthash :c 3 hash-table)
+    (puthash "a" 1 hash-table)
+    (puthash "b" 2 hash-table)
+    (puthash "c" 3 hash-table)
     (should (equal (json-encode hash-table)
                    "{\"a\":1,\"b\":2,\"c\":3}"))))

@@ -261,7 +270,7 @@ Point is moved to beginning of the buffer."
     (should (equal (json-encode plist) "{\"a\":1,\"b\":2,\"c\":3}"))))

 (ert-deftest test-json-encode-alist-with-sort-predicate ()
-  (let ((alist '((:c . 3) (:a . 1) (:b . 2)))
+  (let ((alist '((c . 3) (a . 1) (b . 2)))
         (json-encoding-object-sort-predicate 'string<)
         (json-encoding-pretty-print nil))
     (should (equal (json-encode alist) "{\"a\":1,\"b\":2,\"c\":3}"))))
@@ -270,7 +279,7 @@ Point is moved to beginning of the buffer."
   (let ((json-encoding-pretty-print nil))
     (should (equal (json-encode-list '(:a 1 :b 2))
                    "{\"a\":1,\"b\":2}"))
-    (should (equal (json-encode-list '((:a . 1) (:b . 2)))
+    (should (equal (json-encode-list '((a . 1) (b . 2)))
                    "{\"a\":1,\"b\":2}"))
     (should (equal (json-encode-list '(1 2 3 4)) "[1,2,3,4]"))))

-- 
2.8.1



2016年8月21日(日) 22:32 Yoichi Nakayama <yoichi.nakayama@gmail.com>:

> The change in json-encode-key broke tests in json-tests.el. I'll
> investigate it.
>
> Ran 34 tests, 28 results as expected, 6 unexpected (2016-08-21
> 22:30:23+0900)
>
> 6 unexpected results:
>    FAILED  test-json-encode-alist-with-sort-predicate
>    FAILED  test-json-encode-hash-table
>    FAILED  test-json-encode-key
>    FAILED  test-json-encode-list
>    FAILED  test-json-encode-plist
>    FAILED  test-json-encode-plist-with-sort-predicate
>
> --
> Yoichi NAKAYAMA
>

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