Merge pull request #2069 from danielaskdd/error-message

refactor: Improved Exception Handling with Context-Aware Error Messages

lightrag/operate.py

@@ -31,6 +31,7 @@ from .utils import (
     process_chunks_unified,
     build_file_path,
     safe_vdb_operation_with_exception,
+    create_prefixed_exception,
 )
 from .base import (
     BaseGraphStorage,
@@ -1622,8 +1623,11 @@ async def merge_nodes_and_edges(
                             f"Failed to update pipeline status: {status_error}"
                         )
 
-                    # Re-raise the original exception
+                    # Re-raise the original exception with a prefix
-                    raise
+                    prefixed_exception = create_prefixed_exception(
+                        e, f"`{entity_name}`"
+                    )
+                    raise prefixed_exception from e
 
     # Create entity processing tasks
     entity_tasks = []
@@ -1753,8 +1757,11 @@ async def merge_nodes_and_edges(
                             f"Failed to update pipeline status: {status_error}"
                         )
 
-                    # Re-raise the original exception
+                    # Re-raise the original exception with a prefix
-                    raise
+                    prefixed_exception = create_prefixed_exception(
+                        e, f"`{sorted_edge_key}`"
+                    )
+                    raise prefixed_exception from e
 
     # Create relationship processing tasks
     edge_tasks = []
@@ -2070,11 +2077,14 @@ async def extract_entities(
         if pending:
             await asyncio.wait(pending)
 
-        # Re-raise the first exception to notify the caller
+        # Add progress prefix to the exception message
-        raise first_exception
+        progress_prefix = f"Chunks[{processed_chunks+1}/{total_chunks}]"
+
+        # Re-raise the original exception with a prefix
+        prefixed_exception = create_prefixed_exception(first_exception, progress_prefix)
+        raise prefixed_exception from first_exception
 
     # If all tasks completed successfully, chunk_results already contains the results
-
     # Return the chunk_results for later processing in merge_nodes_and_edges
     return chunk_results
 

lightrag/utils.py

@@ -2588,3 +2588,45 @@ def get_pinyin_sort_key(text: str) -> str:
     else:
         # pypinyin not available, use simple string sorting
         return text.lower()
+
+
+def create_prefixed_exception(original_exception: Exception, prefix: str) -> Exception:
+    """
+    Safely create a prefixed exception that adapts to all error types.
+
+    Args:
+        original_exception: The original exception.
+        prefix: The prefix to add.
+
+    Returns:
+        A new exception with the prefix, maintaining the original exception type if possible.
+    """
+    try:
+        # Method 1: Try to reconstruct using original arguments.
+        if hasattr(original_exception, "args") and original_exception.args:
+            args = list(original_exception.args)
+            # Find the first string argument and prefix it. This is safer for
+            # exceptions like OSError where the first arg is an integer (errno).
+            found_str = False
+            for i, arg in enumerate(args):
+                if isinstance(arg, str):
+                    args[i] = f"{prefix}: {arg}"
+                    found_str = True
+                    break
+
+            # If no string argument is found, prefix the first argument's string representation.
+            if not found_str:
+                args[0] = f"{prefix}: {args[0]}"
+
+            return type(original_exception)(*args)
+        else:
+            # Method 2: If no args, try single parameter construction.
+            return type(original_exception)(f"{prefix}: {str(original_exception)}")
+    except (TypeError, ValueError, AttributeError) as construct_error:
+        # Method 3: If reconstruction fails, wrap it in a RuntimeError.
+        # This is the safest fallback, as attempting to create the same type
+        # with a single string can fail if the constructor requires multiple arguments.
+        return RuntimeError(
+            f"{prefix}: {type(original_exception).__name__}: {str(original_exception)} "
+            f"(Original exception could not be reconstructed: {construct_error})"
+        )