Fix tqdm progress bar conflicts in concurrent RAG evaluation

• Add position pool for tqdm bars
• Serialize tqdm creation with lock
• Set leave=False to clear completed bars
• Pass position/lock to eval tasks
• Import tqdm.auto for better display

lightrag/evaluation/eval_rag_quality.py

@@ -82,7 +82,7 @@ try:
     )
     from ragas.llms import LangchainLLMWrapper
     from langchain_openai import ChatOpenAI, OpenAIEmbeddings
-    from tqdm import tqdm
+    from tqdm.auto import tqdm
 
     RAGAS_AVAILABLE = True
 
@@ -351,6 +351,8 @@ class RAGEvaluator:
         eval_semaphore: asyncio.Semaphore,
         client: httpx.AsyncClient,
         progress_counter: Dict[str, int],
+        position_pool: asyncio.Queue,
+        pbar_creation_lock: asyncio.Lock,
     ) -> Dict[str, Any]:
         """
         Evaluate a single test case with two-stage pipeline concurrency control
@@ -362,6 +364,8 @@ class RAGEvaluator:
             eval_semaphore: Semaphore to control RAGAS evaluation concurrency (Stage 2)
             client: Shared httpx AsyncClient for connection pooling
             progress_counter: Shared dictionary for progress tracking
+            position_pool: Queue of available tqdm position indices
+            pbar_creation_lock: Lock to serialize tqdm creation and prevent race conditions
 
         Returns:
             Evaluation result dictionary
@@ -407,9 +411,22 @@ class RAGEvaluator:
             # concurrent state conflicts when multiple tasks run in parallel
             async with eval_semaphore:
                 pbar = None
+                position = None
                 try:
-                    # Create standard tqdm progress bar for RAGAS evaluation
-                    pbar = tqdm(total=4, desc=f"Eval-{idx}", leave=True)
+                    # Acquire a position from the pool for this tqdm progress bar
+                    position = await position_pool.get()
+
+                    # Serialize tqdm creation to prevent race conditions
+                    # Multiple tasks creating tqdm simultaneously can cause display conflicts
+                    async with pbar_creation_lock:
+                        # Create tqdm progress bar with assigned position to avoid overlapping
+                        # leave=False ensures the progress bar is cleared after completion,
+                        # preventing accumulation of completed bars and allowing position reuse
+                        pbar = tqdm(
+                            total=4, desc=f"Eval-{idx}", position=position, leave=False
+                        )
+                        # Give tqdm time to initialize and claim its screen position
+                        await asyncio.sleep(0.05)
 
                     eval_results = evaluate(
                         dataset=eval_dataset,
@@ -424,9 +441,6 @@ class RAGEvaluator:
                         _pbar=pbar,
                     )
 
-                    pbar.close()
-                    pbar = None
-
                     # Convert to DataFrame (RAGAS v0.3+ API)
                     df = eval_results.to_pandas()
 
@@ -487,6 +501,9 @@ class RAGEvaluator:
                     # Force close progress bar to ensure completion
                     if pbar is not None:
                         pbar.close()
+                    # Release the position back to the pool for reuse
+                    if position is not None:
+                        await position_pool.put(position)
 
     async def evaluate_responses(self) -> List[Dict[str, Any]]:
         """
@@ -513,6 +530,16 @@ class RAGEvaluator:
         # Create progress counter (shared across all tasks)
         progress_counter = {"completed": 0}
 
+        # Create position pool for tqdm progress bars
+        # Positions range from 0 to max_async-1, ensuring no overlapping displays
+        position_pool = asyncio.Queue()
+        for i in range(max_async):
+            await position_pool.put(i)
+
+        # Create lock to serialize tqdm creation and prevent race conditions
+        # This ensures progress bars are created one at a time, avoiding display conflicts
+        pbar_creation_lock = asyncio.Lock()
+
         # Create shared HTTP client with connection pooling and proper timeouts
         # Timeout: 3 minutes for connect, 5 minutes for read (LLM can be slow)
         timeout = httpx.Timeout(
@@ -535,6 +562,8 @@ class RAGEvaluator:
                     eval_semaphore,
                     client,
                     progress_counter,
+                    position_pool,
+                    pbar_creation_lock,
                 )
                 for idx, test_case in enumerate(self.test_cases, 1)
             ]