pr: accept -e at the end of a short flag cluster

src/uu/pr/src/pr.rs

@@ -427,7 +427,9 @@
 fn recreate_arguments(args: &[String]) -> Vec<String> {
     let num_regex = Regex::new(r"^[^-]\d*$").unwrap();
     let n_regex = Regex::new(r"^-n\s*$").unwrap();
-    let e_regex = Regex::new(r"^-e").unwrap();
+    // `-e` ends a cluster of short flags that take no value of their own, as in `-tre`.
+    // Options that do take a value are excluded so that `-se` keeps meaning `-s e`.
+    let e_regex = Regex::new(r"^-[dtTrFfabmJ]*e$").unwrap();
     let mut arguments = args.to_owned();
     let num_option = args
         .iter()
@@ -442,16 +444,15 @@
         arguments.insert(pos + 2, could_be_file);
     }
 
-    // To ensure not to accidentally delete the next argument after a short flag for -e we insert
-    // the default values for the -e flag is '-e' is present without direct arguments.
+    // `-e` takes an optional attached argument, which clap cannot express, so it is filled in
+    // here. Without it clap would report a missing value for `-tre`, or swallow the following
+    // argument, usually a file name, for a bare `-e`.
     let expand_tabs_option = arguments
         .iter()
         .take_while(|arg| arg.as_str() != "--")
         .find_position(|x| e_regex.is_match(x.trim()));
-    if let Some((pos, value)) = expand_tabs_option
-        && value.trim().len() <= 2
-    {
-        arguments[pos] = "-e\t8".to_string();
+    if let Some((pos, value)) = expand_tabs_option {
+        arguments[pos] = format!("{}\t8", value.trim());
     }
 
     // Remove only whole-token legacy operands before clap parsing.

tests/by-util/test_pr.rs

@@ -945,6 +945,34 @@
         .stdout_matches(&output_regex);
 }
 
+#[test]
+fn test_expand_tab_at_end_of_short_flag_cluster() {
+    // `-e` closing a cluster of value-less short flags carries no attached argument, so it has
+    // to fall back to the defaults rather than report a missing value.
+    for (arg, expected) in [
+        ("-tre", "oi\n"),
+        ("-tre8", "oi\n"),
+        ("-tfre", "oi\n\x0c"),
+        ("-tfre8", "oi\n\x0c"),
+    ] {
+        new_ucmd!()
+            .arg(arg)
+            .pipe_in("oi\n")
+            .succeeds()
+            .stdout_only(expected);
+    }
+}
+
+#[test]
+fn test_expand_tab_does_not_consume_following_operand() {
+    // A bare `-e` must leave the file operand alone.
+    new_ucmd!()
+        .args(&["-t", "-e"])
+        .pipe_in("a\tb\n")
+        .succeeds()
+        .stdout_only("a       b\n");
+}
+
 #[test]
 fn test_simple_expand_tab_with_digit_argument() {
     let whitespace = " ".repeat(50);