From 58dfbcd01392296fd496a92695544fc438c06748 Mon Sep 17 00:00:00 2001
From: "Dylan M. Taylor" <dylan@dylanmtaylor.com>
Date: Tue, 3 Nov 2026 15:19:31 +0000
Subject: [PATCH] fix(log): escape control characters in log messages

---
 apps/soundcraft/src/logging.rs       |  8 +++++++-
 apps/soundcraft/src/logging/tests.rs | 11 +++++++++--
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/apps/soundcraft/src/logging.rs b/apps/soundcraft/src/logging.rs
index a040dd08..0a90483c 100644
--- a/apps/soundcraft/src/logging.rs
+++ b/apps/soundcraft/src/logging.rs
@@ -166,7 +166,13 @@ pub fn rotate(dir: &Path) -> std::io::Result<(PathBuf, File)> {
 /// One formatted log line: `<timestamp> <LEVEL> [<thread>] <target>: <message>\n`.
 pub fn format_line(ts: &str, level: log::Level, thread: &str, target: &str, message: &str) -> String {
     let message = message.strip_suffix('\n').unwrap_or(message);
-    format!("{ts} {level:<5} [{thread}] {target}: {message}\n")
+    // Control characters are written escaped: a message quoting a session file (a plugin id, a
+    // path) must not start a line of its own in the log or steer the terminal.
+    let mut escaped = String::with_capacity(message.len());
+    for c in message.chars() {
+        if c.is_control() { escaped.extend(c.escape_default()) } else { escaped.push(c) }
+    }
+    format!("{ts} {level:<5} [{thread}] {target}: {escaped}\n")
 }
 
 /// Where formatted lines go besides standard error: kept in memory until a file is attached,
diff --git a/apps/soundcraft/src/logging/tests.rs b/apps/soundcraft/src/logging/tests.rs
index 1103ba68..ebbc85a5 100644
--- a/apps/soundcraft/src/logging/tests.rs
+++ b/apps/soundcraft/src/logging/tests.rs
@@ -158,8 +158,15 @@ fn a_line_carries_time_level_thread_target_and_message() {
         format_line("2026-10-08T07:59:17.728Z", log::Level::Warn, "main", "soundcraft_mix", "eq_7band: the plugin did not accept its stored state"),
         "2026-10-08T07:59:17.728Z WARN  [main] soundcraft_mix: eq_7band: the plugin did not accept its stored state\n"
     );
-    // A multi-line message keeps its lines; the record still ends in exactly one newline.
-    assert!(format_line("t", log::Level::Error, "w", "x", "a\nb\n").ends_with("x: a\nb\n"));
+    // A message with breaks of its own stays one record; the record still ends in exactly one newline.
+    assert!(
+        format_line("t", log::Level::Error, "w", "x", "a\nb\n").ends_with("x: a\\nb\n"),
+        "a break inside the message is escaped, the final one dropped"
+    );
+    assert!(
+        format_line("t", log::Level::Error, "w", "x", "plugin \u{1b}[2J\r\n2026 INFO forged")
+            .ends_with("x: plugin \\u{1b}[2J\\r\\n2026 INFO forged\n")
+    );
 }
 
 #[test]