fix: throttle ticket progress events to prevent UI freeze

src-tauri/src/services/orchestrator.rs

@@ -10,6 +10,7 @@ use crate::models::worktree::Worktree;
 use crate::services::process_registry::ProcessRegistry;
 use crate::services::{cli_process, notifier, worktree_manager};
 use rusqlite::Connection;
+use std::mem;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::{Arc, Mutex};
 use tauri::{AppHandle, Emitter};
@@ -17,6 +18,9 @@ use tokio::process::Command;
 use tokio::sync::Mutex as AsyncMutex;
 use tokio::time::{interval, timeout, Duration};
 
+const PROGRESS_BUFFER_MAX_BYTES: usize = 2048;
+const PROGRESS_EMIT_INTERVAL_MS: u128 = 250;
+
 #[derive(Debug, Clone, PartialEq)]
 pub enum Verdict {
     FixNeeded,
@@ -207,6 +211,15 @@ fn validate_developer_completion(
     evaluate_developer_completion(developer_report, commits.len(), !diff.trim().is_empty())
 }
 
+fn should_flush_progress_buffer(buffer: &str, elapsed_since_last_emit: std::time::Duration) -> bool {
+    if buffer.is_empty() {
+        return false;
+    }
+
+    buffer.len() >= PROGRESS_BUFFER_MAX_BYTES
+        || elapsed_since_last_emit.as_millis() >= PROGRESS_EMIT_INTERVAL_MS
+}
+
 fn recover_interrupted_tickets(db: &Arc<Mutex<Connection>>) -> Result<usize, String> {
     let inflight = {
         let conn = db.lock().map_err(|e| format!("DB lock failed: {}", e))?;
@@ -305,14 +318,27 @@ pub async fn run_cli_command(
         "Failed to capture stderr".to_string()
     })?;
 
+    let mut progress_buffer = String::new();
+    let mut last_progress_emit = std::time::Instant::now();
     let read_future = cli_process::collect_process_output(child.clone(), stdout, stderr, |line| {
+        if !line.is_empty() {
+            if !progress_buffer.is_empty() {
+                progress_buffer.push('\n');
+            }
+            progress_buffer.push_str(line);
+        }
+
+        if should_flush_progress_buffer(&progress_buffer, last_progress_emit.elapsed()) {
+            let chunk = mem::take(&mut progress_buffer);
             let _ = app_handle.emit(
                 "ticket-processing-progress",
                 serde_json::json!({
                     "ticket_id": ticket_id,
-                "output_chunk": line,
+                    "output_chunk": chunk,
                 }),
             );
+            last_progress_emit = std::time::Instant::now();
+        }
         Ok(())
     });
 
@@ -336,6 +362,17 @@ pub async fn run_cli_command(
             }
         };
 
+    if !progress_buffer.is_empty() {
+        let chunk = mem::take(&mut progress_buffer);
+        let _ = app_handle.emit(
+            "ticket-processing-progress",
+            serde_json::json!({
+                "ticket_id": ticket_id,
+                "output_chunk": chunk,
+            }),
+        );
+    }
+
     process_registry.unregister_ticket(ticket_id);
 
     if cancellation_requested.load(Ordering::SeqCst) {
@@ -959,6 +996,31 @@ mod tests {
         assert_eq!(updated.status, "Pending");
     }
 
+    #[test]
+    fn test_should_flush_progress_buffer_when_elapsed_interval_exceeded() {
+        let should_flush = should_flush_progress_buffer(
+            "some progress",
+            std::time::Duration::from_millis(300),
+        );
+        assert!(should_flush);
+    }
+
+    #[test]
+    fn test_should_flush_progress_buffer_when_buffer_reaches_size_limit() {
+        let payload = "x".repeat(2048);
+        let should_flush = should_flush_progress_buffer(
+            &payload,
+            std::time::Duration::from_millis(10),
+        );
+        assert!(should_flush);
+    }
+
+    #[test]
+    fn test_should_not_flush_progress_buffer_when_empty() {
+        let should_flush = should_flush_progress_buffer("", std::time::Duration::from_secs(1));
+        assert!(!should_flush);
+    }
+
     #[test]
     fn test_evaluate_developer_completion_rejects_permission_block_report() {
         let result = evaluate_developer_completion(