diff -r 0f2268783c11 -r 65839176cea9 rust/rhg/src/ui.rs
--- a/rust/rhg/src/ui.rs	Thu Jan 30 09:23:16 2025 +0100
+++ b/rust/rhg/src/ui.rs	Fri Jan 31 15:04:13 2025 +0000
@@ -12,7 +12,9 @@
 use hg::utils::files::get_bytes_from_path;
 use std::borrow::Cow;
 use std::io;
+use std::io::BufWriter;
 use std::io::IsTerminal;
+use std::io::StdoutLock;
 use std::io::{ErrorKind, Write};
 
 pub struct Ui {
@@ -56,8 +58,11 @@
 
     /// Returns a buffered handle on stdout for faster batch printing
     /// operations.
-    pub fn stdout_buffer(&self) -> StdoutBuffer<std::io::StdoutLock> {
-        StdoutBuffer::new(self.stdout.lock())
+    pub fn stdout_buffer(&self) -> StdoutBuffer<'_, BufWriter<StdoutLock>> {
+        StdoutBuffer {
+            stdout: BufWriter::new(self.stdout.lock()),
+            colors: &self.colors,
+        }
     }
 
     /// Write bytes to stdout
@@ -77,13 +82,21 @@
 
         stderr.flush().or_else(handle_stderr_error)
     }
+}
 
+/// A buffered stdout writer for faster batch printing operations.
+pub struct StdoutBuffer<'a, W> {
+    colors: &'a Option<ColorConfig>,
+    stdout: W,
+}
+
+impl<'a, W: Write> StdoutBuffer<'a, W> {
     /// Write bytes to stdout with the given label
     ///
     /// Like the optional `label` parameter in `mercurial/ui.py`,
     /// this label influences the color used for this output.
     pub fn write_stdout_labelled(
-        &self,
+        &mut self,
         bytes: &[u8],
         label: &str,
     ) -> Result<(), UiError> {
@@ -96,15 +109,15 @@
                 }
             }
         }
-        self.write_stdout(bytes)
+        self.write_all(bytes)
     }
 
     fn write_stdout_with_effects(
-        &self,
+        &mut self,
         bytes: &[u8],
         effects: &[Effect],
     ) -> io::Result<()> {
-        let stdout = &mut self.stdout.lock();
+        let stdout = &mut self.stdout;
         let mut write_line = |line: &[u8], first: bool| {
             // `line` does not include the newline delimiter
             if !first {
@@ -130,7 +143,17 @@
                 write_line(line, false)?
             }
         }
-        stdout.flush()
+        Ok(())
+    }
+
+    /// Write bytes to stdout buffer
+    pub fn write_all(&mut self, bytes: &[u8]) -> Result<(), UiError> {
+        self.stdout.write_all(bytes).or_else(handle_stdout_error)
+    }
+
+    /// Flush bytes to stdout
+    pub fn flush(&mut self) -> Result<(), UiError> {
+        self.stdout.flush().or_else(handle_stdout_error)
     }
 }
 
@@ -144,28 +167,6 @@
     }
 }
 
-/// A buffered stdout writer for faster batch printing operations.
-pub struct StdoutBuffer<W: Write> {
-    buf: io::BufWriter<W>,
-}
-
-impl<W: Write> StdoutBuffer<W> {
-    pub fn new(writer: W) -> Self {
-        let buf = io::BufWriter::new(writer);
-        Self { buf }
-    }
-
-    /// Write bytes to stdout buffer
-    pub fn write_all(&mut self, bytes: &[u8]) -> Result<(), UiError> {
-        self.buf.write_all(bytes).or_else(handle_stdout_error)
-    }
-
-    /// Flush bytes to stdout
-    pub fn flush(&mut self) -> Result<(), UiError> {
-        self.buf.flush().or_else(handle_stdout_error)
-    }
-}
-
 /// Sometimes writing to stdout is not possible, try writing to stderr to
 /// signal that failure, otherwise just bail.
 fn handle_stdout_error(error: io::Error) -> Result<(), UiError> {