From c5fd64ba975ee35df17bb0c335efb00bffce4d91 Mon Sep 17 00:00:00 2001
From: Emanuele Torre <torreemanuele6@gmail.com>
Date: Wed, 13 Dec 2023 20:14:31 +0100
Subject: [PATCH] jv_parse: let decNumberFromString/strtod parse complex nans
 as a NaN

Before this patch (when using decNumber), "Nan123" was parsed as a NaN,
only if the first n was uppercase.
---
 src/jv_parse.c | 2 +-
 tests/jq.test  | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/jv_parse.c b/src/jv_parse.c
index 110483a4..9755b8ac 100644
--- a/src/jv_parse.c
+++ b/src/jv_parse.c
@@ -514,7 +514,7 @@ static pfunc check_literal(struct jv_parser* p) {
   case 'f': pattern = "false"; plen = 5; v = jv_false(); break;
   case 'n':
     // if it starts with 'n', it could be a literal "nan"
-    if (p->tokenpos != 3) {
+    if (p->tokenbuf[1] == 'u') {
       pattern = "null"; plen = 4; v = jv_null();
     }
   }
diff --git a/tests/jq.test b/tests/jq.test
index 4c8416dc..7036df2c 100644
--- a/tests/jq.test
+++ b/tests/jq.test
@@ -1938,6 +1938,11 @@ tojson | fromjson
 {"a":nan}
 {"a":null}
 
+# also "nan with payload" #2985
+fromjson | isnan
+"nan1234"
+true
+
 
 # calling input/0, or debug/0 in a test doesn't crash jq