From 07f6da561c8edcd98971ceca614ff9364a83e361 Mon Sep 17 00:00:00 2001
From: Grzegorz <19194188+farce1@users.noreply.github.com>
Date: Sun, 14 Jun 2026 12:25:11 +0200
Subject: [PATCH] fix(transcription): survive a recognizer panic instead of
 killing the worker

A Rust panic inside the Whisper recognizer's transcribe call unwound the worker
thread, ending transcription for the rest of the meeting (the forwarder then
marks it degraded). Wrap the call in catch_unwind so a single bad chunk is
skipped and the worker keeps going. Mirrors Handy's catch_unwind-around-the-engine
practice.
---
 src-tauri/src/transcription/worker.rs | 30 ++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/src-tauri/src/transcription/worker.rs b/src-tauri/src/transcription/worker.rs
index f29885a..758b8a5 100644
--- a/src-tauri/src/transcription/worker.rs
+++ b/src-tauri/src/transcription/worker.rs
@@ -13,6 +13,12 @@ const ASR_SAMPLE_RATE: u32 = 16_000;
 const WHISPER_MAX_DECODE_SECONDS: usize = 25;
 const WHISPER_MAX_DECODE_SAMPLES: usize = (ASR_SAMPLE_RATE as usize) * WHISPER_MAX_DECODE_SECONDS;
 
+// Run the ASR call under catch_unwind so one panicking chunk skips instead of
+// killing the worker thread (and with it transcription for the rest of the meeting).
+fn catch_panic<T>(operation: impl FnOnce() -> T) -> Option<T> {
+    std::panic::catch_unwind(std::panic::AssertUnwindSafe(operation)).ok()
+}
+
 pub struct WorkerConfig {
     pub model_dir: PathBuf,
     pub vad_model: String,
@@ -36,7 +42,13 @@ fn process_completed_segments(
                 continue;
             }
 
-            let result = recognizer.transcribe(ASR_SAMPLE_RATE, samples);
+            let result = match catch_panic(|| recognizer.transcribe(ASR_SAMPLE_RATE, samples)) {
+                Some(result) => result,
+                None => {
+                    eprintln!("[transcription] recognizer panicked on a chunk; skipping it");
+                    continue;
+                }
+            };
             let text = result.text.trim().to_string();
             if text.is_empty() {
                 continue;
@@ -194,3 +206,19 @@ pub fn run_worker(
         config.recording_start_ms,
     );
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn catch_panic_returns_value_on_success() {
+        assert_eq!(catch_panic(|| 42u32), Some(42));
+    }
+
+    #[test]
+    fn catch_panic_returns_none_when_closure_panics() {
+        let result: Option<u32> = catch_panic(|| panic!("simulated engine panic"));
+        assert_eq!(result, None);
+    }
+}