fix(streaming): type the text completion chunk builder so its scans add no basedpyright debt

Read chunk fields as typed attributes instead of untyped subscripts, which
clears the reportUnknownArgumentType breach the lint gate flagged

litellm/main.py

@@ -13,6 +13,7 @@ import asyncio
 import contextvars
 import datetime
 import inspect
+import itertools
 import json
 import os
 import random
@@ -8837,49 +8838,43 @@ def config_completion(**kwargs):
         )
 
 
-def stream_chunk_builder_text_completion(chunks: list, messages: Sequence | None = None) -> TextCompletionResponse:
-    id: Final = chunks[0]["id"]
-    object: Final = chunks[0]["object"]
-    created: Final = chunks[0]["created"]
-    model: Final = chunks[0]["model"]
+def stream_chunk_builder_text_completion(
+    chunks: Sequence[TextCompletionResponse], messages: Sequence | None = None
+) -> TextCompletionResponse:
+    id: Final = chunks[0].id
+    object: Final = chunks[0].object
+    created: Final = chunks[0].created
+    model: Final = chunks[0].model
     system_fingerprint: Final = chunks[0].get("system_fingerprint", None)
     # With stream_options.include_usage the last chunk is a usage-only trailer, and some providers
     # (e.g. vLLM) send finish_reason on a text-less chunk before it, so scan rather than read chunks[-1].
-    chunks_with_choices: Final = [chunk for chunk in chunks if chunk["choices"]]
+    chunks_with_choices: Final = [chunk for chunk in chunks if chunk.choices]
     finish_reason: Final = next(
-        (c["choices"][0]["finish_reason"] for c in reversed(chunks_with_choices) if c["choices"][0]["finish_reason"]),
+        (c.choices[0].finish_reason for c in reversed(chunks_with_choices) if c.choices[0].finish_reason),
         None,
     )
-    logprobs: Final = chunks_with_choices[-1]["choices"][0]["logprobs"] if chunks_with_choices else None
+    logprobs: Final = chunks_with_choices[-1].choices[0].logprobs if chunks_with_choices else None
 
-    content_list: Final = []
-    for chunk in chunks:
-        choices = chunk["choices"]
-        for choice in choices:
-            if choice is not None and hasattr(choice, "text") and choice.get("text") is not None:
-                _choice = choice.get("text")
-                content_list.append(_choice)
-
-    # Combine the "content" strings into a single string || combine the 'function' strings into a single string
-    combined_content: Final = "".join(content_list)
+    all_choices: Final = itertools.chain.from_iterable(chunk.choices for chunk in chunks)
+    combined_content: Final = "".join(choice.text for choice in all_choices if choice.text)
 
     # Prefer the usage the provider reported (the include_usage trailer) over a local recount, which
     # cannot see a text-completion prompt (it is not in `messages`) and so reports 0 prompt tokens.
     provider_usage: Final = next(
-        (c.get("usage") for c in reversed(chunks) if c.get("usage") and c["usage"].get("total_tokens")),
+        (c.usage for c in reversed(chunks) if c.usage and c.usage.total_tokens),
         None,
     )
     if provider_usage is not None:
-        prompt_tokens = provider_usage.get("prompt_tokens") or 0
-        completion_tokens = provider_usage.get("completion_tokens") or 0
+        prompt_tokens = provider_usage.prompt_tokens
+        completion_tokens = provider_usage.completion_tokens
     else:
         try:
-            prompt_tokens = token_counter(model=model, messages=messages)
+            prompt_tokens = token_counter(model=model or "", messages=messages)
         except Exception:  # don't allow this failing to block a complete streaming response from being returned
             print_verbose("token_counter failed, assuming prompt tokens is 0")
             prompt_tokens = 0
         completion_tokens = token_counter(
-            model=model,
+            model=model or "",
             text=combined_content,
             count_response_tokens=True,  # count_response_tokens is a Flag to tell token counter this is a response, No need to add extra tokens we do for input messages
         )