ls: fix exit code for --time-style when used

src/uu/ls/src/ls.rs

@@ -966,7 +966,12 @@ impl Config {
 
         let mut quoting_style = extract_quoting_style(options, show_control);
         let indicator_style = extract_indicator_style(options);
-        let time_style = parse_time_style(options)?;
+        // Only parse the value to "--time-style" if it will become relevant.
+        let time_style = if format == Format::Long {
+            parse_time_style(options)?
+        } else {
+            TimeStyle::Iso
+        };
 
         let mut ignore_patterns: Vec<Pattern> = Vec::new();
 

tests/by-util/test_ls.rs

@@ -86,6 +86,31 @@ fn test_invalid_value_returns_2() {
     }
 }
 
+#[test]
+fn test_invalid_value_time_style() {
+    // This is the only flag which does not raise an error if it is invalid but not actually used:
+    new_ucmd!()
+        .arg("--time-style=definitely_invalid_value")
+        .succeeds()
+        .no_stderr()
+        .code_is(0);
+    // If it is used, error:
+    new_ucmd!()
+        .arg("-g")
+        .arg("--time-style=definitely_invalid_value")
+        .fails()
+        .no_stdout()
+        .code_is(2);
+    // If it only looks temporarily like it might be used, no error:
+    new_ucmd!()
+        .arg("-l")
+        .arg("--time-style=definitely_invalid_value")
+        .arg("--format=single-column")
+        .succeeds()
+        .no_stderr()
+        .code_is(0);
+}
+
 #[test]
 fn test_ls_ls() {
     new_ucmd!().succeeds();