Merge pull request #5811 from spineki/fix-printf-hex-alternate-zero

Printf: Fix printf hex alternate zero

src/uucore/src/lib/features/format/num_format.rs

@@ -156,13 +156,21 @@ impl Formatter for UnsignedInt {
                 format!("{x:x}")
             }
             UnsignedIntVariant::Hexadecimal(Case::Lowercase, Prefix::Yes) => {
-                format!("{x:#x}")
+                if x == 0 {
+                    "0".to_string()
+                } else {
+                    format!("{x:#x}")
+                }
             }
             UnsignedIntVariant::Hexadecimal(Case::Uppercase, Prefix::No) => {
                 format!("{x:X}")
             }
             UnsignedIntVariant::Hexadecimal(Case::Uppercase, Prefix::Yes) => {
-                format!("{x:#X}")
+                if x == 0 {
+                    "0".to_string()
+                } else {
+                    format!("{x:#X}")
+                }
             }
         };
 

tests/by-util/test_printf.rs

@@ -645,6 +645,32 @@ fn partial_char() {
         );
 }
 
+#[test]
+fn sub_alternative_lower_hex_0() {
+    new_ucmd!().args(&["%#x", "0"]).succeeds().stdout_only("0");
+}
+
+#[test]
+fn sub_alternative_lower_hex() {
+    new_ucmd!()
+        .args(&["%#x", "42"])
+        .succeeds()
+        .stdout_only("0x2a");
+}
+
+#[test]
+fn sub_alternative_upper_hex_0() {
+    new_ucmd!().args(&["%#X", "0"]).succeeds().stdout_only("0");
+}
+
+#[test]
+fn sub_alternative_upper_hex() {
+    new_ucmd!()
+        .args(&["%#X", "42"])
+        .succeeds()
+        .stdout_only("0x2A");
+}
+
 #[test]
 fn char_as_byte() {
     new_ucmd!().args(&["%c", "🙃"]).succeeds().stdout_only("ð");