patch 8.1.0731: JS encoding does not handle negative infinity

Problem:    JS encoding does not handle negative infinity.
Solution:   Add support for negative infinity for JS encoding. (Dominique
            Pelle, closes #3792)

runtime/doc/eval.txt

@@ -5726,7 +5726,8 @@ json_decode({string})					*json_decode()*
 		  "[1, 2, ]" is the same as "[1, 2]".
 		- More floating point numbers are recognized, e.g. "1." for
 		  "1.0", or "001.2" for "1.2". Special floating point values
-		  "Infinity" and "NaN" (capitalization ignored) are accepted.
+		  "Infinity", "-Infinity" and "NaN" (capitalization ignored)
+		  are accepted.
 		- Leading zeroes in integer numbers are ignored, e.g. "012"
 		  for "12" or "-012" for "-12".
 		- Capitalization is ignored in literal names null, true or
@@ -5755,6 +5756,7 @@ json_encode({expr})					*json_encode()*
 		   Float		floating point number
 		   Float nan		"NaN"
 		   Float inf		"Infinity"
+		   Float -inf		"-Infinity"
 		   String		in double quotes (possibly null)
 		   Funcref		not possible, error
 		   List			as an array (possibly null); when

src/json.c

@@ -316,7 +316,12 @@ json_encode_item(garray_T *gap, typval_T *val, int copyID, int options)
 	    if (isnan(val->vval.v_float))
 		ga_concat(gap, (char_u *)"NaN");
 	    else if (isinf(val->vval.v_float))
+	    {
+		if (val->vval.v_float < 0.0)
+		    ga_concat(gap, (char_u *)"-Infinity");
+		else
 		    ga_concat(gap, (char_u *)"Infinity");
+	    }
 	    else
 # endif
 	    {
@@ -736,7 +741,7 @@ json_decode_item(js_read_T *reader, typval_T *res, int options)
 		    break;
 
 		default:
-		    if (VIM_ISDIGIT(*p) || *p == '-')
+		    if (VIM_ISDIGIT(*p) || (*p == '-' && VIM_ISDIGIT(p[1])))
 		    {
 #ifdef FEAT_FLOAT
 			char_u  *sp = p;
@@ -834,6 +839,17 @@ json_decode_item(js_read_T *reader, typval_T *res, int options)
 			retval = OK;
 			break;
 		    }
+		    if (STRNICMP((char *)p, "-Infinity", 9) == 0)
+		    {
+			reader->js_used += 9;
+			if (cur_item != NULL)
+			{
+			    cur_item->v_type = VAR_FLOAT;
+			    cur_item->vval.v_float = -INFINITY;
+			}
+			retval = OK;
+			break;
+		    }
 		    if (STRNICMP((char *)p, "Infinity", 8) == 0)
 		    {
 			reader->js_used += 8;
@@ -851,6 +867,7 @@ json_decode_item(js_read_T *reader, typval_T *res, int options)
 		    if (
 			    (len < 5 && STRNICMP((char *)p, "false", len) == 0)
 #ifdef FEAT_FLOAT
+			    || (len < 9 && STRNICMP((char *)p, "-Infinity", len) == 0)
 			    || (len < 8 && STRNICMP((char *)p, "Infinity", len) == 0)
 			    || (len < 3 && STRNICMP((char *)p, "NaN", len) == 0)
 #endif
@@ -1072,7 +1089,7 @@ json_decode(js_read_T *reader, typval_T *res, int options)
  * Return FAIL if the message has a decoding error.
  * Return MAYBE if the message is truncated, need to read more.
  * This only works reliable if the message contains an object, array or
- * string.  A number might be trucated without knowing.
+ * string.  A number might be truncated without knowing.
  * Does not advance the reader.
  */
     int

src/testdir/test_json.vim

@@ -29,8 +29,10 @@ let s:varnr = 1234
 if has('float')
   let s:jsonfl = '12.34'
   let s:varfl = 12.34
-  let s:jsoninf = 'Infinity'
+  let s:jsonneginf = '-Infinity'
-  let s:varinf = 1.0 / 0.0
+  let s:jsonposinf = 'Infinity'
+  let s:varneginf = -1.0 / 0.0
+  let s:varposinf = 1.0 / 0.0
   let s:jsonnan = 'NaN'
   let s:varnan = 0.0 / 0.0
 endif
@@ -85,7 +87,8 @@ func Test_json_encode()
   call assert_equal(s:jsonnr, json_encode(s:varnr))
   if has('float')
     call assert_equal(s:jsonfl, json_encode(s:varfl))
-    call assert_equal(s:jsoninf, json_encode(s:varinf))
+    call assert_equal(s:jsonneginf, json_encode(s:varneginf))
+    call assert_equal(s:jsonposinf, json_encode(s:varposinf))
     call assert_equal(s:jsonnan, json_encode(s:varnan))
   endif
 
@@ -202,7 +205,8 @@ func Test_js_encode()
   call assert_equal(s:jsonnr, js_encode(s:varnr))
   if has('float')
     call assert_equal(s:jsonfl, js_encode(s:varfl))
-    call assert_equal(s:jsoninf, js_encode(s:varinf))
+    call assert_equal(s:jsonneginf, js_encode(s:varneginf))
+    call assert_equal(s:jsonposinf, js_encode(s:varposinf))
     call assert_equal(s:jsonnan, js_encode(s:varnan))
   endif
 
@@ -242,7 +246,8 @@ func Test_js_decode()
   call assert_equal(s:varnr, js_decode(s:jsonnr))
   if has('float')
     call assert_equal(s:varfl, js_decode(s:jsonfl))
-    call assert_equal(s:varinf, js_decode(s:jsoninf))
+    call assert_equal(s:varneginf, js_decode(s:jsonneginf))
+    call assert_equal(s:varposinf, js_decode(s:jsonposinf))
     call assert_true(isnan(js_decode(s:jsonnan)))
   endif
 

src/version.c

@@ -795,6 +795,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    731,
 /**/
     730,
 /**/