printf: trim leading whitespace when parsing numeric values

Trim leading whitespace from numeric input to printf.

Author: dlrobertson

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

@@ -181,11 +181,13 @@ impl ParsedNumber {
             };
         }
 
+        let trimmed_input = input.trim_ascii_start();
+
         // Initial minus sign
-        let (negative, unsigned) = if let Some(input) = input.strip_prefix('-') {
+        let (negative, unsigned) = if let Some(input) = trimmed_input.strip_prefix('-') {
             (true, input)
         } else {
-            (false, input)
+            (false, trimmed_input)
         };
 
         // Parse an optional base prefix ("0b" / "0B" / "0" / "0x" / "0X"). "0" is octal unless a
@@ -384,4 +386,24 @@ mod tests {
         assert_eq!(Ok(0b1011), ParsedNumber::parse_u64("0b1011"));
         assert_eq!(Ok(0b1011), ParsedNumber::parse_u64("0B1011"));
     }
+
+    #[test]
+    fn test_parsing_with_leading_whitespace() {
+        assert_eq!(Ok(1), ParsedNumber::parse_u64(" 0x1"));
+        assert_eq!(Ok(-2), ParsedNumber::parse_i64(" -0x2"));
+        assert_eq!(Ok(-3), ParsedNumber::parse_i64(" \t-0x3"));
+        assert_eq!(Ok(-4), ParsedNumber::parse_i64(" \n-0x4"));
+        assert_eq!(Ok(-5), ParsedNumber::parse_i64(" \n\t\u{000d}-0x5"));
+
+        // Ensure that trailing whitespace is still a partial match
+        assert_eq!(Err(ParseError::PartialMatch(6, " ")), ParsedNumber::parse_u64("0x6 "));
+        assert_eq!(Err(ParseError::PartialMatch(7, "\t")), ParsedNumber::parse_u64("0x7\t"));
+        assert_eq!(Err(ParseError::PartialMatch(8, "\n")), ParsedNumber::parse_u64("0x8\n"));
+
+        // Ensure that unicode non-ascii whitespace is a partial match
+        assert_eq!(Err(ParseError::NotNumeric), ParsedNumber::parse_i64("\u{2029}-0x9"));
+
+        // Ensure that whitespace after the number has "started" is not allowed
+        assert_eq!(Err(ParseError::NotNumeric), ParsedNumber::parse_i64("- 0x9"));
+    }
 }

tests/by-util/test_printf.rs

@@ -1036,3 +1036,21 @@ fn float_switch_switch_decimal_scientific() {
         .succeeds()
         .stdout_only("1e-05");
 }
+
+#[test]
+fn float_arg_with_whitespace() {
+    new_ucmd!()
+        .args(&["%f", " \u{0020}\u{000d}\t\n0.000001"])
+        .succeeds()
+        .stdout_only("0.000001");
+
+    new_ucmd!()
+        .args(&["%f", "0.1 "])
+        .fails()
+        .stderr_contains("value not completely converted");
+
+    new_ucmd!()
+        .args(&["%f", "\u{2029}0.1"])
+        .fails()
+        .stderr_contains("expected a numeric value");
+}