quoting: use single quotes for apostrophe names with C1 controls

src/uucore/src/lib/features/quoting_style/mod.rs

@@ -447,6 +447,25 @@ mod tests {
         );
     }
 
+    #[test]
+    fn test_c1_control_chars_with_single_quote() {
+        for (name, expected) in [
+            ("it's\u{9b}here", "'it'\\''s'$'\\302\\233''here'"),
+            ("\u{9b}it's", "''$'\\302\\233''it'\\''s'"),
+            ("it's\u{9b}", "'it'\\''s'$'\\302\\233'"),
+            ("it's\u{e9}", "\"it's\u{e9}\""),
+        ] {
+            check_names_encoding(
+                UEncoding::Utf8,
+                name,
+                &[
+                    (expected, "shell-escape"),
+                    (expected, "shell-escape-always"),
+                ],
+            );
+        }
+    }
+
     #[test]
     fn test_simple_names() {
         check_names_both(

src/uucore/src/lib/features/quoting_style/shell_quoter.rs

@@ -134,11 +134,16 @@ impl<'a> EscapedShellQuoter<'a> {
         let (mut quotes, must_quote) = initial_quoting(reference, dirname, always_quote, true);
         // Dollar-quoted byte escapes cannot be nested in double quotes.
         if quotes == ShellQuotes::Double {
-            let invalid = match encoding {
+            let needs_dollar = match encoding {
                 UEncoding::Ascii => !reference.is_ascii(),
-                UEncoding::Utf8 => std::str::from_utf8(reference).is_err(),
+                UEncoding::Utf8 => std::str::from_utf8(reference).map_or(true, |name| {
+                    name.chars().any(|c| {
+                        let escaped = EscapedChar::new_shell(c, true, ShellQuotes::Double);
+                        matches!(escaped.state, EscapeState::Octal(_))
+                    })
+                }),
             };
-            if invalid {
+            if needs_dollar {
                 quotes = ShellQuotes::Single;
             }
         }

tests/by-util/test_printf.rs

@@ -1104,6 +1104,15 @@ fn test_q_string_control_chars_with_quotes() {
         .stdout_only("''$'\\001'\\'''$'\\001'");
 }
 
+#[test]
+fn test_q_string_c1_control_char_with_quote() {
+    new_ucmd!()
+        .env("LC_ALL", "en_US.UTF-8")
+        .args(&["%q", "it's\u{9b}here"])
+        .succeeds()
+        .stdout_only("'it'\\''s'$'\\302\\233''here'");
+}
+
 // Output with no trailing newline stays in the buffer until the process exits,
 // so the failure is only visible when it is flushed.
 #[test]