From 4dae902429ee0a54a46cd219526a2493e312c3bf Mon Sep 17 00:00:00 2001
From: Terts Diepraam <terts.diepraam@gmail.com>
Date: Wed, 7 Feb 2024 12:38:25 +0100
Subject: [PATCH] printf: pad octal numbers with zeros on the left

---
 .../src/lib/features/format/num_format.rs     |  8 ++++--
 tests/by-util/test_printf.rs                  | 28 +++++++++++++++++++
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/src/uucore/src/lib/features/format/num_format.rs b/src/uucore/src/lib/features/format/num_format.rs
index 607c028c3..819ba6a5f 100644
--- a/src/uucore/src/lib/features/format/num_format.rs
+++ b/src/uucore/src/lib/features/format/num_format.rs
@@ -143,11 +143,13 @@ impl Formatter for UnsignedInt {
             UnsignedIntVariant::Octal(Prefix::No) => format!("{x:o}"),
             UnsignedIntVariant::Octal(Prefix::Yes) => {
                 // The prefix that rust uses is `0o`, but GNU uses `0`.
-                // We also need to take into account that 0 should not be 00
+                // We also need to take into account that 0 should not be 00 and
+                // that GNU pads prefixed octals with zeros.
+                //
                 // Since this is an unsigned int, we do not need to take the minus
                 // sign into account.
-                if x == 0 {
-                    format!("{x:o}")
+                if x < 8u64.pow(self.precision.saturating_sub(1) as u32) {
+                    format!("{x:0>width$o}", width = self.precision)
                 } else {
                     format!("0{x:o}")
                 }
diff --git a/tests/by-util/test_printf.rs b/tests/by-util/test_printf.rs
index db4c5aa7f..86d9060ae 100644
--- a/tests/by-util/test_printf.rs
+++ b/tests/by-util/test_printf.rs
@@ -680,3 +680,31 @@ fn char_as_byte() {
 fn no_infinite_loop() {
     new_ucmd!().args(&["a", "b"]).succeeds().stdout_only("a");
 }
+
+#[test]
+fn pad_octal_with_prefix() {
+    new_ucmd!()
+        .args(&[">%#15.6o<", "0"])
+        .succeeds()
+        .stdout_only(">         000000<");
+
+    new_ucmd!()
+        .args(&[">%#15.6o<", "01"])
+        .succeeds()
+        .stdout_only(">         000001<");
+
+    new_ucmd!()
+        .args(&[">%#15.6o<", "01234"])
+        .succeeds()
+        .stdout_only(">         001234<");
+
+    new_ucmd!()
+        .args(&[">%#15.6o<", "012345"])
+        .succeeds()
+        .stdout_only(">         012345<");
+
+    new_ucmd!()
+        .args(&[">%#15.6o<", "0123456"])
+        .succeeds()
+        .stdout_only(">        0123456<");
+}