feat(progress): Detect OSC 9;4 in tmux and Herdr

Recognize tmux 3.7+ through TERM_PROGRAM and TERM_PROGRAM_VERSION,
including patch suffixes such as 3.7b. Recognize Herdr by TERM_PROGRAM.

tmux exposes progress to status formats and emits it to clients with
Spb, supplied by terminfo, built-in mappings, or configuration.
Automatic Ghostty progressbar recognition requires tmux 3.8.
Herdr consumes progress for agent detection, not a generic visible bar.

These hints work in native and remote panes without probing. Preserve
the TTY gate and document detection inputs. Test tmux version parsing
directly, covering boundaries, patch suffixes, malformed values, and
overflow.

Author: dbast

crates/anstyle-progress/src/query.rs

@@ -63,9 +63,66 @@ pub fn supports_term_progress(is_terminal: bool) -> bool {
         return true;
     }
 
+    // Terminal multiplexers
+    //
+    // Environment variables used for detection:
+    // | Multiplexer | Variable             | Value       |
+    // |-------------|----------------------|-------------|
+    // | cmux        | TERM_PROGRAM         | ghostty     |
+    // | Herdr       | TERM_PROGRAM         | herdr       |
+    // | screen      | (none)               | Not enabled |
+    // | tmux        | TERM_PROGRAM         | tmux        |
+    // |             | TERM_PROGRAM_VERSION | >= 3.7      |
+    // | Zellij      | (none)               | Not enabled |
+    //
+    // cmux is a terminal app and already matches the Ghostty check above.
+    // screen has no verified raw OSC 9;4 support.
+    // Zellij: https://github.com/zellij-org/zellij/issues/4531
+
+    // Herdr 0.6.9 added OSC 9;4 capture in
+    // https://github.com/herdrdev/herdr/commit/82468a0e03360219898ebf3735bdf559182009f8
+    if term_program.as_deref() == Some("herdr") {
+        return true;
+    }
+
+    // tmux 3.7 added OSC 9;4 handling and forwarding to capable client terminals.
+    // https://github.com/tmux/tmux/blob/3.7/CHANGES
+    if term_program.as_deref() == Some("tmux")
+        && std::env::var("TERM_PROGRAM_VERSION")
+            .ok()
+            .map(|version| tmux_version_has_progress(&version))
+            .unwrap_or(false)
+    {
+        return true;
+    }
+
     false
 }
 
+fn tmux_version_has_progress(version: &str) -> bool {
+    let Some((major, minor)) = version.split_once('.') else {
+        return false;
+    };
+    // tmux patch releases append a lowercase letter, for example "3.7b".
+    let minor = match minor.as_bytes().last() {
+        Some(ch) if ch.is_ascii_lowercase() => &minor[..minor.len() - 1],
+        _ => minor,
+    };
+    if major.is_empty()
+        || minor.is_empty()
+        || !major
+            .bytes()
+            .chain(minor.bytes())
+            .all(|ch| ch.is_ascii_digit())
+    {
+        return false;
+    }
+    match (major.parse::<u32>(), minor.parse::<u32>()) {
+        (Ok(major), Ok(minor)) => (major, minor) >= (3, 7),
+        _ => false,
+    }
+}
+
 // For iTerm, the TERM_FEATURES value "P" indicates OSC 9;4 support.
 //
 // Context: https://iterm2.com/feature-reporting/
@@ -91,7 +148,7 @@ fn term_features_has_progress(value: &str) -> bool {
 
 #[cfg(test)]
 mod tests {
-    use super::term_features_has_progress;
+    use super::{term_features_has_progress, tmux_version_has_progress};
 
     #[test]
     fn term_features_progress_detection() {
@@ -101,4 +158,28 @@ mod tests {
         // Without PROGRESS feature
         assert!(!term_features_has_progress("MBT2Sc"));
     }
+
+    #[test]
+    fn tmux_progress_detection() {
+        for (version, expected) in [
+            ("3.6b", false),
+            ("3.7", true),
+            ("3.7b", true),
+            ("3.8", true),
+            ("3.10", true),
+            ("4.0", true),
+            ("2.10", false),
+            ("", false),
+            ("next-3.7", false),
+            ("3.7junk", false),
+            ("3.7.0", false),
+            ("3.", false),
+            ("3.a", false),
+            ("+3.7", false),
+            ("3.+7", false),
+            ("4294967296.7", false),
+        ] {
+            assert_eq!(tmux_version_has_progress(version), expected, "{version:?}");
+        }
+    }
 }