Merge 8e78990f01 into 431ecd8920

litellm/types/utils.py

@@ -1832,6 +1832,23 @@ class PromptTokensDetailsWrapper(
         if self.cached_tokens_details is None:
             del self.cached_tokens_details
 
+    def __getattr__(self, name: str):
+        """Return declared defaults for payload-hygiene deletions (issue #43756).
+
+        __init__ deletes None-valued fields from the instance dict so they stay
+        out of serialized payloads; pydantic v2 then raises on direct attribute
+        access to those deleted fields. This fallback returns the declared
+        class default instead, so downstream direct reads
+        (e.g. wrapper.cache_creation_tokens on a first-turn response with no
+        cache activity) behave like a zero-valued field rather than crashing.
+        """
+        field_info = type(self).model_fields.get(name)
+        if field_info is not None:
+            return field_info.get_default()
+        raise AttributeError(
+            f"{type(self).__name__!s} object has no attribute {name!r}"
+        )
+
 
 class ServerToolUse(BaseModel):
     web_search_requests: int | None = None

tests/unit/test_utils.py

@@ -156,11 +156,16 @@ def test_usage_anthropic_cache_creation_maps_to_cache_write_tokens():
 
 
 def test_prompt_tokens_details_no_cache_write_tokens_when_absent():
-    """A read-only cache hit (no cache write) must not surface cache-write fields."""
+    """A read-only cache hit (no cache write) must not surface cache-write fields
+    in the serialized payload; direct reads of deleted fields return the declared
+    defaults instead of raising AttributeError (issue #43756)."""
     details = PromptTokensDetailsWrapper(cached_tokens=800)
     assert details.cached_tokens == 800
-    assert not hasattr(details, "cache_write_tokens")
-    assert not hasattr(details, "cache_creation_tokens")
+    assert details.cache_write_tokens is None
+    assert details.cache_creation_tokens is None
+    dumped = details.model_dump()
+    assert "cache_write_tokens" not in dumped
+    assert "cache_creation_tokens" not in dumped
 
 
 def test_prompt_tokens_details_cache_write_creation_stay_in_sync_on_assignment():
@@ -176,6 +181,32 @@ def test_prompt_tokens_details_cache_write_creation_stay_in_sync_on_assignment()
     assert details.cache_write_tokens == details.cache_creation_tokens == 375
 
 
+def test_prompt_tokens_details_none_cache_fields_read_as_none():
+    """Direct reads of deleted None-valued fields must return the declared
+    defaults instead of raising AttributeError (issue #43756)."""
+    wrapper = PromptTokensDetailsWrapper(
+        prompt_tokens=100,
+        cache_creation_tokens=None,
+        cache_read_input_tokens=None,
+        cache_write_tokens=None,
+    )
+    assert wrapper.cache_creation_tokens is None
+    assert wrapper.cache_write_tokens is None
+
+
+def test_prompt_tokens_details_dump_excludes_deleted_none_fields():
+    """Payload hygiene survives: deleted None fields stay out of model_dump."""
+    wrapper = PromptTokensDetailsWrapper(
+        prompt_tokens=100,
+        cache_creation_tokens=None,
+        cache_read_input_tokens=None,
+        cache_write_tokens=None,
+    )
+    dumped = wrapper.model_dump()
+    assert "cache_write_tokens" not in dumped
+    assert "cache_creation_tokens" not in dumped
+
+
 def test_potential_model_names_keeps_provider_prefixed_candidate():
     """A provider whose own model ids repeat the litellm provider name (Perplexity's
     Agent API serves `perplexity/glm-5.2`, mapped as `perplexity/perplexity/glm-5.2`)