From 33ac58383c499e19e92c3effefa1c4641861851a Mon Sep 17 00:00:00 2001
From: Tommaso Fellegara <96147629+Felle33@users.noreply.github.com>
Date: Thu, 9 Jan 2025 09:20:48 +0100
Subject: [PATCH] csplit: fix bug when --suppress-matched flag is active and
 positive/negative offset is present (#7088)

* tests/csplit: modified test test_up_to_match_offset_option_suppress_matched according to issue #7052 and modified also test_up_to_match_negative_offset_option_suppress_matched

* csplit: managed the positive and negative offset when the --suppressed-matched flag is active

* tests/csplit: modified test test_up_to_match_offset_option_suppress_matched according to issue #7052 and modified also test_up_to_match_negative_offset_option_suppress_matched

* csplit: managed the positive and negative offset when the --suppressed-matched flag is active

* csplit: swapped if and else blocks for better readability
---
 src/uu/csplit/src/csplit.rs  | 19 ++++++++++++++++++-
 tests/by-util/test_csplit.rs | 10 +++++-----
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/src/uu/csplit/src/csplit.rs b/src/uu/csplit/src/csplit.rs
index 329b06d36..d654c9271 100644
--- a/src/uu/csplit/src/csplit.rs
+++ b/src/uu/csplit/src/csplit.rs
@@ -372,6 +372,7 @@ impl SplitWriter<'_> {
             while let Some((ln, line)) = input_iter.next() {
                 let l = line?;
                 if regex.is_match(&l) {
+                    let mut next_line_suppress_matched = false;
                     match (self.options.suppress_matched, offset) {
                         // no offset, add the line to the next split
                         (false, 0) => {
@@ -382,6 +383,11 @@ impl SplitWriter<'_> {
                         }
                         // a positive offset, some more lines need to be added to the current split
                         (false, _) => self.writeln(&l)?,
+                        // suppress matched option true, but there is a positive offset, so the line is printed
+                        (true, 1..) => {
+                            next_line_suppress_matched = true;
+                            self.writeln(&l)?;
+                        }
                         _ => (),
                     };
                     offset -= 1;
@@ -402,6 +408,11 @@ impl SplitWriter<'_> {
                         offset -= 1;
                     }
                     self.finish_split();
+
+                    // if we have to suppress one line after we take the next and do nothing
+                    if next_line_suppress_matched {
+                        input_iter.next();
+                    }
                     return Ok(());
                 }
                 self.writeln(&l)?;
@@ -420,7 +431,12 @@ impl SplitWriter<'_> {
                     for line in input_iter.shrink_buffer_to_size() {
                         self.writeln(&line)?;
                     }
-                    if !self.options.suppress_matched {
+                    if self.options.suppress_matched {
+                        // since offset_usize is for sure greater than 0
+                        // the first element of the buffer should be removed and this
+                        // line inserted to be coherent with GNU implementation
+                        input_iter.add_line_to_buffer(ln, l);
+                    } else {
                         // add 1 to the buffer size to make place for the matched line
                         input_iter.set_size_of_buffer(offset_usize + 1);
                         assert!(
@@ -428,6 +444,7 @@ impl SplitWriter<'_> {
                             "should be big enough to hold every lines"
                         );
                     }
+
                     self.finish_split();
                     if input_iter.buffer_len() < offset_usize {
                         return Err(CsplitError::LineOutOfRange(pattern_as_str.to_string()));
diff --git a/tests/by-util/test_csplit.rs b/tests/by-util/test_csplit.rs
index 231571522..9323b9851 100644
--- a/tests/by-util/test_csplit.rs
+++ b/tests/by-util/test_csplit.rs
@@ -469,14 +469,14 @@ fn test_up_to_match_offset_option_suppress_matched() {
     let (at, mut ucmd) = at_and_ucmd!();
     ucmd.args(&["numbers50.txt", "--suppress-matched", "/10/+4"])
         .succeeds()
-        .stdout_only("27\n111\n");
+        .stdout_only("30\n108\n");
 
     let count = glob(&at.plus_as_string("xx*"))
         .expect("there should be splits created")
         .count();
     assert_eq!(count, 2);
-    assert_eq!(at.read("xx00"), generate(1, 10) + &generate(11, 14));
-    assert_eq!(at.read("xx01"), generate(14, 51));
+    assert_eq!(at.read("xx00"), generate(1, 14));
+    assert_eq!(at.read("xx01"), generate(15, 51));
 }
 
 #[test]
@@ -484,14 +484,14 @@ fn test_up_to_match_negative_offset_option_suppress_matched() {
     let (at, mut ucmd) = at_and_ucmd!();
     ucmd.args(&["numbers50.txt", "--suppress-matched", "/10/-4"])
         .succeeds()
-        .stdout_only("10\n128\n");
+        .stdout_only("10\n129\n");
 
     let count = glob(&at.plus_as_string("xx*"))
         .expect("there should be splits created")
         .count();
     assert_eq!(count, 2);
     assert_eq!(at.read("xx00"), generate(1, 6));
-    assert_eq!(at.read("xx01"), generate(6, 10) + &generate(11, 51));
+    assert_eq!(at.read("xx01"), generate(7, 51));
 }
 
 #[test]