Json mode nested models (#263)

instructor/patch.py

@@ -107,6 +107,10 @@ def handle_response_model(
                     the parsed objects in json that match the following json_schema (do not deviate at all and its okay if you cant be exact):\n
                     {response_model.model_json_schema()['properties']}
                     """
+                # Check for nested models
+                if "$defs" in response_model.model_json_schema():
+                    message += f"\nHere are some more definitions to adhere too:\n{response_model.model_json_schema()['$defs']}"
+
                 new_kwargs["messages"].append(
                     {
                         "role": "assistant",

tests/openai/evals/test_nested_structures.py

@@ -47,3 +47,52 @@ def test_nested(mode):
     assert {x.name.lower() for x in resp.items} == {"apple", "bread", "milk"}
     assert {x.price for x in resp.items} == {0.5, 2.0, 1.5}
     assert resp.customer.lower() == "jason"
+
+
+class Book(BaseModel):
+    title: str
+    author: str
+    genre: str
+    isbn: str
+
+
+class LibraryRecord(BaseModel):
+    books: List[Book] = Field(..., default_factory=list)
+    visitor: str
+    library_id: str
+
+
+@pytest.mark.parametrize("mode", [Mode.FUNCTIONS, Mode.JSON, Mode.TOOLS, Mode.MD_JSON])
+def test_complex_nested_model(mode):
+    client = instructor.patch(OpenAI(), mode=mode)
+
+    content = """
+    Library visit details:
+    Visitor: Jason
+    Library ID: LIB123456
+    Books checked out:
+    - Title: The Great Adventure, Author: Jane Doe, Genre: Fantasy, ISBN: 1234567890
+    - Title: History of Tomorrow, Author: John Smith, Genre: Non-Fiction, ISBN: 0987654321
+    """
+
+    resp = client.chat.completions.create(
+        model="gpt-3.5-turbo-1106",
+        response_model=LibraryRecord,
+        messages=[
+            {
+                "role": "user",
+                "content": content,
+            },
+        ],
+    )
+
+    assert resp.visitor.lower() == "jason"
+    assert resp.library_id == "LIB123456"
+    assert len(resp.books) == 2
+    assert {book.title for book in resp.books} == {
+        "The Great Adventure",
+        "History of Tomorrow",
+    }
+    assert {book.author for book in resp.books} == {"Jane Doe", "John Smith"}
+    assert {book.genre for book in resp.books} == {"Fantasy", "Non-Fiction"}
+    assert {book.isbn for book in resp.books} == {"1234567890", "0987654321"}