printer: preserve line terminator when using --crlf and --replace

Ref #3097, Closes #3100

crates/printer/src/standard.rs

@@ -3947,4 +3947,41 @@ e
         let expected = "4:d\n5-e\n6:d\n";
         assert_eq_printed!(expected, got);
     }
+
+    #[test]
+    fn regression_crlf_preserve() {
+        let haystack = "hello\nworld\r\n";
+        let matcher =
+            RegexMatcherBuilder::new().crlf(true).build(r".").unwrap();
+        let mut printer = StandardBuilder::new().build(NoColor::new(vec![]));
+        let mut searcher = SearcherBuilder::new()
+            .line_number(false)
+            .line_terminator(LineTerminator::crlf())
+            .build();
+
+        searcher
+            .search_reader(
+                &matcher,
+                haystack.as_bytes(),
+                printer.sink(&matcher),
+            )
+            .unwrap();
+        let got = printer_contents(&mut printer);
+        let expected = "hello\nworld\r\n";
+        assert_eq_printed!(expected, got);
+
+        let mut printer = StandardBuilder::new()
+            .replacement(Some(b"$0".to_vec()))
+            .build(NoColor::new(vec![]));
+        searcher
+            .search_reader(
+                &matcher,
+                haystack.as_bytes(),
+                printer.sink(&matcher),
+            )
+            .unwrap();
+        let got = printer_contents(&mut printer);
+        let expected = "hello\nworld\r\n";
+        assert_eq_printed!(expected, got);
+    }
 }

crates/printer/src/util.rs

@@ -59,19 +59,23 @@ impl<M: Matcher> Replacer<M> {
         // See the giant comment in 'find_iter_at_in_context' below for why we
         // do this dance.
         let is_multi_line = searcher.multi_line_with_matcher(&matcher);
-        if is_multi_line {
+        // Get the line_terminator that was removed (if any) so we can add it back
+        let line_terminator = if is_multi_line {
             if haystack[range.end..].len() >= MAX_LOOK_AHEAD {
                 haystack = &haystack[..range.end + MAX_LOOK_AHEAD];
             }
+            &[]
         } else {
             // When searching a single line, we should remove the line
             // terminator. Otherwise, it's possible for the regex (via
             // look-around) to observe the line terminator and not match
             // because of it.
             let mut m = Match::new(0, range.end);
-            trim_line_terminator(searcher, haystack, &mut m);
+            let line_terminator =
+                trim_line_terminator(searcher, haystack, &mut m);
             haystack = &haystack[..m.end()];
-        }
+            line_terminator
+        };
         {
             let &mut Space { ref mut dst, ref mut caps, ref mut matches } =
                 self.allocate(matcher)?;
@@ -81,6 +85,7 @@ impl<M: Matcher> Replacer<M> {
             replace_with_captures_in_context(
                 matcher,
                 haystack,
+                line_terminator,
                 range.clone(),
                 caps,
                 dst,
@@ -508,6 +513,7 @@ where
         // Otherwise, it's possible for the regex (via look-around) to observe
         // the line terminator and not match because of it.
         let mut m = Match::new(0, range.end);
+        // No need to rember the line terminator as we aren't doing a replace here
         trim_line_terminator(searcher, bytes, &mut m);
         bytes = &bytes[..m.end()];
     }
@@ -523,19 +529,23 @@ where
 
 /// Given a buf and some bounds, if there is a line terminator at the end of
 /// the given bounds in buf, then the bounds are trimmed to remove the line
-/// terminator.
-pub(crate) fn trim_line_terminator(
+/// terminator, returning the slice of the removed line terminator (if any).
+pub(crate) fn trim_line_terminator<'b>(
     searcher: &Searcher,
-    buf: &[u8],
+    buf: &'b [u8],
     line: &mut Match,
-) {
+) -> &'b [u8] {
     let lineterm = searcher.line_terminator();
     if lineterm.is_suffix(&buf[*line]) {
         let mut end = line.end() - 1;
         if lineterm.is_crlf() && end > 0 && buf.get(end - 1) == Some(&b'\r') {
             end -= 1;
         }
+        let orig_end = line.end();
         *line = line.with_end(end);
+        &buf[end..orig_end]
+    } else {
+        &[]
     }
 }
 
@@ -545,6 +555,7 @@ pub(crate) fn trim_line_terminator(
 fn replace_with_captures_in_context<M, F>(
     matcher: M,
     bytes: &[u8],
+    line_terminator: &[u8],
     range: std::ops::Range<usize>,
     caps: &mut M::Captures,
     dst: &mut Vec<u8>,
@@ -566,6 +577,8 @@ where
     })?;
     let end = std::cmp::min(bytes.len(), range.end);
     dst.extend(&bytes[last_match..end]);
+    // Add back any line terminator
+    dst.extend(line_terminator);
     Ok(())
 }