From afa23a53cde43cbd7d6e5d91ae759e342d518de6 Mon Sep 17 00:00:00 2001
From: fhgffy <102001626+fhgffy@users.noreply.github.com>
Date: Tue, 20 Oct 2026 21:16:56 +0800
Subject: [PATCH] Keep the sign of zero when negating a number literal (#3662)

Since jq 1.8.0, negating a number literal computed 0 - x, so -0 and
0 | -. printed 0 while (0+0) | -. printed -0.

Flip the sign bit with decNumberCopyNegate() instead, so -0 prints -0
again as it did in jq 1.7, and -(-0) is still 0.
---
 src/jv.c      | 2 +-
 tests/jq.test | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/jv.c b/src/jv.c
index 76d2bf82..930fb6fb 100644
--- a/src/jv.c
+++ b/src/jv.c
@@ -758,7 +758,7 @@ jv jv_number_negate(jv n) {
   if (JVP_HAS_FLAGS(n, JVP_FLAGS_NUMBER_LITERAL)) {
     jvp_literal_number* m = jvp_literal_number_alloc(jvp_dec_number_ptr(n)->digits);
 
-    decNumberMinus(&m->num_decimal, jvp_dec_number_ptr(n), DEC_CONTEXT());
+    decNumberCopyNegate(&m->num_decimal, jvp_dec_number_ptr(n));
     jv r = {JVP_FLAGS_NUMBER_LITERAL, 0, 0, 0, {&m->refcnt}};
     return r;
   }
diff --git a/tests/jq.test b/tests/jq.test
index d45ecd24..557432d9 100644
--- a/tests/jq.test
+++ b/tests/jq.test
@@ -2443,6 +2443,11 @@ true
 null
 true
 
+# Unary negation keeps the sign of zero
+[-0, -(-0), (.[] | -.)] | map(tojson)
+[0, -0]
+["-0","0","-0","0"]
+
 . |= try . catch .
 1
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