Parse nan in JSON as NaN instead of triggering a parse error (#2712)

* Fix memory leak for has(nan)

jv_array_get() used to be responsible of freeing the input array, but
since b5c4c3d67decec22d34f494a200af59bbcadcc80, it is no longer called
if the key is nan. We need to free it manually to avoid leaking the
array.

* Parse  nan  in JSON as NaN instead of triggering a parse error

Fixes #2021

3 files changed, 18 insertions, 1 deletions

diff --git a/src/jv_aux.c b/src/jv_aux.c
index 3153d6e6..6a5efa94 100644
--- a/src/jv_aux.c
+++ b/src/jv_aux.c
@@ -215,6 +215,7 @@ jv jv_has(jv t, jv k) {
   } else if (jv_get_kind(t) == JV_KIND_ARRAY &&
              jv_get_kind(k) == JV_KIND_NUMBER) {
     if (jvp_number_is_nan(k)) {
+      jv_free(t);
       ret = jv_false();
     } else {
       jv elem = jv_array_get(t, (int)jv_number_value(k));
diff --git a/src/jv_parse.c b/src/jv_parse.c
index e91f65d0..2caf330b 100644
--- a/src/jv_parse.c
+++ b/src/jv_parse.c
@@ -490,7 +490,11 @@ static pfunc check_literal(struct jv_parser* p) {
   switch (p->tokenbuf[0]) {
   case 't': pattern = "true"; plen = 4; v = jv_true(); break;
   case 'f': pattern = "false"; plen = 5; v = jv_false(); break;
-  case 'n': pattern = "null"; plen = 4; v = jv_null(); break;
+  case 'n':
+    // if it starts with 'n', it could be a literal "nan"
+    if (p->tokenpos != 3) {
+      pattern = "null"; plen = 4; v = jv_null();
+    }
   }
   if (pattern) {
     if (p->tokenpos != plen) return "Invalid literal";
diff --git a/tests/jq.test b/tests/jq.test
index 3182c1f3..4a8bfeee 100644
--- a/tests/jq.test
+++ b/tests/jq.test
@@ -1799,6 +1799,18 @@ reduce .[] as $then (4 as $else | $else; . as $elif | . + $then * $elif)
 
 
 # { $__loc__ } works
+
 { a, $__loc__, c }
 {"a":[1,2,3],"b":"foo","c":{"hi":"hey"}}
 {"a":[1,2,3],"__loc__":{"file":"<top-level>","line":1},"c":{"hi":"hey"}}
+
+
+# nan is parsed as a valid NaN value from JSON
+
+fromjson | isnan
+"nan"
+true
+
+tojson | fromjson
+{"a":nan}
+{"a":null}