Chore/community context clean (#1262)

* Update community_context.py to check conversation_history_context's value

For the following code (line 90 - 96), conversation_history_context is concatenated with community_context, but the case where conversation_history_context is empty("") has not been considered. When conversation_history_context is empty (""), concatenation should not be performed, as it would result in community_context or each element in community_context having an extra "\n\n".

Therefore, by introducing a context_prefix to check the state of conversation_history_context, concatenation can be handled appropriately. When conversation_history_context is empty (""), the following code will use "" for concatenation. When conversation_history_context is not empty (""), the functionality will be similar to the previous code.

* Format and semver

* Code cleanup

---------

Co-authored-by: ZeyuTeng96 <[email protected]>

.semversioner/next-release/patch-20241009221929632018.json

@@ -0,0 +1,4 @@
+{
+  "type": "patch",
+  "description": "Small cleanup in community context history building"
+}

graphrag/query/structured_search/global_search/community_context.py

@@ -87,13 +87,21 @@ def build_context(
             context_name=context_name,
             random_state=self.random_state,
         )
-        if isinstance(community_context, list):
-            final_context = [
-                f"{conversation_history_context}\n\n{context}"
-                for context in community_context
-            ]
-        else:
-            final_context = f"{conversation_history_context}\n\n{community_context}"
 
+        # Prepare context_prefix based on whether conversation_history_context exists
+        context_prefix = (
+            f"{conversation_history_context}\n\n"
+            if conversation_history_context
+            else ""
+        )
+
+        final_context = (
+            [f"{context_prefix}{context}" for context in community_context]
+            if isinstance(community_context, list)
+            else f"{context_prefix}{community_context}"
+        )
+
+        # Update the final context data with the provided community_context_data
         final_context_data.update(community_context_data)
-        return (final_context, final_context_data)
+
+        return final_context, final_context_data