From 550a0b4286858d6d32eb916941f4a9a7d2493269 Mon Sep 17 00:00:00 2001
From: sarankumar1325 <120080287+sarankumar1325@users.noreply.github.com>
Date: Sun, 25 Oct 2026 21:00:16 +0530
Subject: [PATCH] cut: trim Unicode blanks with -w=trimmed

In a UTF-8 locale the whitespace matcher splits fields on Unicode blanks
such as U+3000, but -w=trimmed only stripped SPACE and TAB from the ends
of a line. A leading Unicode blank then emptied field 1 and shifted every
word, a trailing one added an empty last field, and -s kept one-word
lines. Trim with the same matcher that splits the fields, and update the
help text, which still said Space/Tab only.

Fixes #15819
---
 src/uu/cut/locales/en-US.ftl |  2 +-
 src/uu/cut/src/cut.rs        | 24 ++++++++++++++++++------
 tests/by-util/test_cut.rs    | 29 +++++++++++++++++++++++++++++
 3 files changed, 48 insertions(+), 7 deletions(-)

diff --git a/src/uu/cut/locales/en-US.ftl b/src/uu/cut/locales/en-US.ftl
index 6e63feb2638..4d40825784d 100644
--- a/src/uu/cut/locales/en-US.ftl
+++ b/src/uu/cut/locales/en-US.ftl
@@ -20,7 +20,7 @@ cut-after-help = If no FILE is specified, reads from stdin. Use '-' as a FILE ar
 cut-help-bytes = extract bytes listed in LIST
 cut-help-characters = extract characters listed in LIST
 cut-help-delimiter = use DELIM as field separator (default: Tab)
-cut-help-whitespace-delimited = use any whitespace (Space/Tab) as delimiter; ignore leading and trailing blanks with 'trimmed'
+cut-help-whitespace-delimited = use any run of blanks (Space/Tab, plus Unicode spaces in a UTF-8 locale) as delimiter; ignore leading and trailing blanks with 'trimmed'
 cut-help-fields = extract fields listed in LIST
 cut-help-fields-merged = like -f, but merge adjacent delimiters; the delimiter defaults to whitespace and the output delimiter to a space
 cut-help-complement = invert selection: print all columns except the specified ones
diff --git a/src/uu/cut/src/cut.rs b/src/uu/cut/src/cut.rs
index 9680ece4a02..9e8a2d6ab79 100644
--- a/src/uu/cut/src/cut.rs
+++ b/src/uu/cut/src/cut.rs
@@ -780,19 +780,31 @@ fn cut_fields_whitespace_trimmed<R: Read, W: Write>(
     newline_char: u8,
     out_delim: &[u8],
 ) -> UResult<()> {
-    let is_blank = |&b: &u8| b == b' ' || b == b'\t';
     let matcher = WhitespaceMatcher {};
     let mut buf_in = BufReader::new(reader);
 
     // Trimming is the only difference from the plain whitespace path: once the
     // outer blanks are gone, the remaining blank runs are ordinary delimiters.
+    // The ends are trimmed with the same matcher that splits the fields, so
+    // in a UTF-8 locale a Unicode blank at either end is trimmed rather than
+    // turned into a leading or trailing delimiter.
     buf_in
         .for_byte_record(newline_char, |line| {
-            let start = line.iter().position(|b| !is_blank(b)).unwrap_or(line.len());
-            let end = line
-                .iter()
-                .rposition(|b| !is_blank(b))
-                .map_or(start, |p| p + 1);
+            let start = match matcher.next_match(line) {
+                Some((0, run_end)) => run_end,
+                _ => 0,
+            };
+            let rest = &line[start..];
+            let mut end = rest.len();
+            let mut pos = 0;
+            while let Some((run_start, run_end)) = matcher.next_match(&rest[pos..]) {
+                if pos + run_end == rest.len() {
+                    end = pos + run_start;
+                    break;
+                }
+                pos += run_end;
+            }
+            let end = start + end;
 
             write_fields_line(
                 &line[start..end],
diff --git a/tests/by-util/test_cut.rs b/tests/by-util/test_cut.rs
index 294863baa73..a8420c179d3 100644
--- a/tests/by-util/test_cut.rs
+++ b/tests/by-util/test_cut.rs
@@ -834,6 +834,35 @@ fn test_whitespace_delimited_trimmed_zero_terminated() {
         .stdout_only_bytes(&b"amber\0"[..]);
 }
 
+#[test]
+#[cfg_attr(wasi_runner, ignore = "WASI: the guest does not inherit LC_ALL")]
+#[cfg(target_os = "linux")]
+fn test_whitespace_delimited_trimmed_unicode_blanks() {
+    // In a UTF-8 locale the field splitter treats Unicode blanks such as
+    // U+3000 (e3 80 80) as delimiters, so trimming must strip them too, or a
+    // leading one empties field 1 and a trailing one adds an empty last field.
+    new_ucmd!()
+        .env("LC_ALL", "C.UTF-8")
+        .args(&["-w=trimmed", "-f1"])
+        .pipe_in(&b"\xe3\x80\x80shutdown now\n"[..])
+        .succeeds()
+        .stdout_only("shutdown\n");
+    new_ucmd!()
+        .env("LC_ALL", "C.UTF-8")
+        .args(&["-w=trimmed", "-f2-", "--output-delimiter=|"])
+        .pipe_in(&b" \xe3\x80\x80red\xe2\x80\x83blue \xe3\x80\x80\n"[..])
+        .succeeds()
+        .stdout_only("blue\n");
+    // A one-word line padded with Unicode blanks has no delimiter left after
+    // trimming, so -s drops it.
+    new_ucmd!()
+        .env("LC_ALL", "C.UTF-8")
+        .args(&["-s", "-w=trimmed", "-f1"])
+        .pipe_in(&b"\xe3\x80\x80alone\xe3\x80\x80\nnot alone\n"[..])
+        .succeeds()
+        .stdout_only("not\n");
+}
+
 #[test]
 #[cfg_attr(wasi_runner, ignore = "WASI: the guest does not inherit LC_ALL")]
 #[cfg(target_os = "linux")]