From 89d17d54ce7b9b4822d518db568fdae128ee5aee Mon Sep 17 00:00:00 2001
From: sueun-dev <sueun.dev@gmail.com>
Date: Tue, 23 Jun 2026 09:35:12 +0900
Subject: [PATCH] Preserve full precision for non-integer numbers in jq output

jsonScalarToString formatted non-integer float64 values with two
decimal places, so jq.Evaluate truncated them: 3.14159 became 3.14
and 0.001 became 0.00. That contradicts the package's documented
behavior of writing values 'similar to how jq --raw works', and the
0.001 -> 0.00 case turns a nonzero value into zero.

Use FormatFloat with precision -1, which produces the shortest string
that round-trips the float64. Integer-valued floats are unchanged.
---
 pkg/jq/jq.go      |  2 +-
 pkg/jq/jq_test.go | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/pkg/jq/jq.go b/pkg/jq/jq.go
index 5f19e1f6..d49e3f57 100644
--- a/pkg/jq/jq.go
+++ b/pkg/jq/jq.go
@@ -104,7 +104,7 @@ func jsonScalarToString(input interface{}) (string, error) {
 		if math.Trunc(tt) == tt {
 			return strconv.FormatFloat(tt, 'f', 0, 64), nil
 		} else {
-			return strconv.FormatFloat(tt, 'f', 2, 64), nil
+			return strconv.FormatFloat(tt, 'f', -1, 64), nil
 		}
 	case nil:
 		return "", nil
diff --git a/pkg/jq/jq_test.go b/pkg/jq/jq_test.go
index 1264de97..4dc5b726 100644
--- a/pkg/jq/jq_test.go
+++ b/pkg/jq/jq_test.go
@@ -172,6 +172,16 @@ func TestEvaluateFormatted(t *testing.T) {
 				" \x1b[32m\"bar\"\x1b[m\n" +
 				"\x1b[1;38m}\x1b[m\n",
 		},
+		{
+			name: "non-integer numbers keep full precision",
+			args: args{
+				json:     strings.NewReader(`{"pi": 3.14159, "small": 0.001, "big": 123456.789}`),
+				expr:     `.pi, .small, .big`,
+				indent:   "",
+				colorize: false,
+			},
+			wantW: "3.14159\n0.001\n123456.789\n",
+		},
 		{
 			name: "halt function",
 			args: args{