forbid scientific notation in numfmt #11655 (#11721)

* forbid scientific notation arguments in numfmt

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* Edit solution of #116555

* add scientific notation test

* change variable name

* use is_ascii_digit() instead of checking manually

Co-authored-by: Daniel Hofstetter <daniel.hofstetter@42dh.com>

* Apply suggestion from @cakebaker

Co-authored-by: Daniel Hofstetter <daniel.hofstetter@42dh.com>

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Daniel Hofstetter <daniel.hofstetter@42dh.com>

Author: 3 people

src/uu/numfmt/src/numfmt.rs

@@ -49,6 +49,19 @@ fn format_and_write<W: std::io::Write>(
         None => input_line,
     };
 
+    // Return false if the input is in scientific notation
+    if let Some(pos) = line.iter().position(|&b| b == b'E' || b == b'e') {
+        if pos < line.len() - 1 {
+            if line[pos + 1].is_ascii_digit() {
+                let err = format!(
+                    "invalid suffix in input: '{}'",
+                    String::from_utf8_lossy(line)
+                );
+                return Err(Box::new(NumfmtError::FormattingError(err)));
+            }
+        }
+    }
+
     // In non-abort modes we buffer the formatted output so that on error we
     // can emit the original line instead.
     let buffer_output = !matches!(options.invalid, InvalidModes::Abort);

tests/by-util/test_numfmt.rs

@@ -1404,7 +1404,6 @@ fn test_large_integer_precision_loss_issue_11654() {
 // uutils accepts scientific notation (`1e9`, `5e-3`, ...); GNU rejects it
 // as "invalid suffix in input".
 #[test]
-#[ignore = "GNU compat: see uutils/coreutils#11655"]
 fn test_scientific_notation_rejected_by_gnu_issue_11655() {
     new_ucmd!()
         .arg("1e9")