From b3c8700481eeec5875cbe33df81242f9e5eb90c3 Mon Sep 17 00:00:00 2001
From: fixfon <12512757+fixfon@users.noreply.github.com>
Date: Fri, 23 Oct 2026 12:25:20 +0300
Subject: [PATCH 1/3] numfmt: print an unsigned zero when rounding a negative
 number to zero

round_with_precision turns a small negative value into -0.0, and
format_float prints the sign of a negative zero, so `-0.3` with
`--round=up --format=%.0f` came out as `-0` (and `-0000` when
zero-padded). Drop the sign of a zero produced by rounding on the
plain path. The --to path keeps its existing `-0` output.

Closes #15661
---
 src/uu/numfmt/src/format.rs  | 10 ++++++----
 tests/by-util/test_numfmt.rs | 12 ++++++++++++
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/src/uu/numfmt/src/format.rs b/src/uu/numfmt/src/format.rs
index 2196a865fb6..155e8b80b7f 100644
--- a/src/uu/numfmt/src/format.rs
+++ b/src/uu/numfmt/src/format.rs
@@ -735,10 +735,12 @@ fn transform_to(
         }
     };
     Ok(match s {
-        None if opts.to == Unit::None && precision <= u16::MAX.into() => localize(format_float(
-            round_with_precision(i2, round_method, precision),
-            precision,
-        )),
+        None if opts.to == Unit::None && precision <= u16::MAX.into() => {
+            let rounded = round_with_precision(i2, round_method, precision);
+            // rounding a small negative number leaves -0.0, which would print as "-0"
+            let rounded = if rounded == 0.0 { 0.0 } else { rounded };
+            localize(format_float(rounded, precision))
+        }
         None if is_precision_specified && precision <= u16::MAX.into() => {
             let i2 = round_with_precision(i2, round_method, 0);
             localize(format_float(i2, precision))
diff --git a/tests/by-util/test_numfmt.rs b/tests/by-util/test_numfmt.rs
index 822f498180f..0ff31e64014 100644
--- a/tests/by-util/test_numfmt.rs
+++ b/tests/by-util/test_numfmt.rs
@@ -254,6 +254,18 @@ fn test_negative_zero() {
         .stdout_is("0\n0.0");
 }
 
+// https://github.com/uutils/coreutils/issues/15661
+// A negative number that rounds to zero prints an unsigned zero, except with `--to`.
+#[rstest]
+#[case::round_up_format_precision(&["--round=up", "--format=%.0f", "--", "-0.3"], "0\n")]
+#[case::to_unit_round_nearest(&["--to-unit=10", "--round=nearest", "--", "-3"], "0\n")]
+#[case::zero_padded(&["--round=up", "--format=%05.0f", "--", "-0.3"], "00000\n")]
+#[case::fractional_precision(&["--round=nearest", "--format=%.1f", "--", "-0.04"], "0.0\n")]
+#[case::to_si_keeps_signed_zero(&["--to=si", "--", "-0.4"], "-0\n")]
+fn test_negative_number_rounded_to_zero(#[case] args: &[&str], #[case] expected: &str) {
+    new_ucmd!().args(args).succeeds().stdout_only(expected);
+}
+
 #[test]
 fn test_no_op() {
     new_ucmd!()

From 1dd119a93af761d78e07de9b139b01cea757c111 Mon Sep 17 00:00:00 2001
From: fixfon <12512757+fixfon@users.noreply.github.com>
Date: Fri, 23 Oct 2026 12:38:22 +0300
Subject: [PATCH 2/3] numfmt: drop a duplicated --to=si test case

---
 tests/by-util/test_numfmt.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/tests/by-util/test_numfmt.rs b/tests/by-util/test_numfmt.rs
index 0ff31e64014..b102c8cb235 100644
--- a/tests/by-util/test_numfmt.rs
+++ b/tests/by-util/test_numfmt.rs
@@ -255,13 +255,12 @@ fn test_negative_zero() {
 }
 
 // https://github.com/uutils/coreutils/issues/15661
-// A negative number that rounds to zero prints an unsigned zero, except with `--to`.
+// A negative number that rounds to zero prints an unsigned zero.
 #[rstest]
 #[case::round_up_format_precision(&["--round=up", "--format=%.0f", "--", "-0.3"], "0\n")]
 #[case::to_unit_round_nearest(&["--to-unit=10", "--round=nearest", "--", "-3"], "0\n")]
 #[case::zero_padded(&["--round=up", "--format=%05.0f", "--", "-0.3"], "00000\n")]
 #[case::fractional_precision(&["--round=nearest", "--format=%.1f", "--", "-0.04"], "0.0\n")]
-#[case::to_si_keeps_signed_zero(&["--to=si", "--", "-0.4"], "-0\n")]
 fn test_negative_number_rounded_to_zero(#[case] args: &[&str], #[case] expected: &str) {
     new_ucmd!().args(args).succeeds().stdout_only(expected);
 }

From 66b5283a77270bfd0d58b4bcc530a0768d650ba7 Mon Sep 17 00:00:00 2001
From: fixfon <12512757+fixfon@users.noreply.github.com>
Date: Fri, 23 Oct 2026 14:25:51 +0300
Subject: [PATCH 3/3] numfmt: drop issue link comment

---
 tests/by-util/test_numfmt.rs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/tests/by-util/test_numfmt.rs b/tests/by-util/test_numfmt.rs
index b102c8cb235..036da1c09cc 100644
--- a/tests/by-util/test_numfmt.rs
+++ b/tests/by-util/test_numfmt.rs
@@ -254,7 +254,6 @@ fn test_negative_zero() {
         .stdout_is("0\n0.0");
 }
 
-// https://github.com/uutils/coreutils/issues/15661
 // A negative number that rounds to zero prints an unsigned zero.
 #[rstest]
 #[case::round_up_format_precision(&["--round=up", "--format=%.0f", "--", "-0.3"], "0\n")]