community: fix perplexity response parameters not being included in model response (#30440)

This pull request includes enhancements to the `perplexity.py` file in
the `chat_models` module, focusing on improving the handling of
additional keyword arguments (`additional_kwargs`) in message processing
methods. Additionally, new unit tests have been added to ensure the
correct inclusion of citations, images, and related questions in the
`additional_kwargs`.

Issue: resolves https://github.com/langchain-ai/langchain/issues/30439

Enhancements to `perplexity.py`:

*
[`libs/community/langchain_community/chat_models/perplexity.py`](diffhunk://#diff-d3e4d7b277608683913b53dcfdbd006f0f4a94d110d8b9ac7acf855f1f22207fL208-L212):
Modified the `_convert_delta_to_message_chunk`, `_stream`, and
`_generate` methods to handle `additional_kwargs`, which include
citations, images, and related questions.
[[1]](diffhunk://#diff-d3e4d7b277608683913b53dcfdbd006f0f4a94d110d8b9ac7acf855f1f22207fL208-L212)
[[2]](diffhunk://#diff-d3e4d7b277608683913b53dcfdbd006f0f4a94d110d8b9ac7acf855f1f22207fL277-L286)
[[3]](diffhunk://#diff-d3e4d7b277608683913b53dcfdbd006f0f4a94d110d8b9ac7acf855f1f22207fR324-R331)

New unit tests:

*
[`libs/community/tests/unit_tests/chat_models/test_perplexity.py`](diffhunk://#diff-dab956d79bd7d17a0f5dea3f38ceab0d583b43b63eb1b29138ee9b6b271ba1d9R119-R275):
Added new tests `test_perplexity_stream_includes_citations_and_images`
and `test_perplexity_stream_includes_citations_and_related_questions` to
verify that the `stream` method correctly includes citations, images,
and related questions in the `additional_kwargs`.

libs/community/langchain_community/chat_models/perplexity.py

@@ -345,16 +345,25 @@ class ChatPerplexity(BaseChatModel):
             if len(chunk["choices"]) == 0:
                 continue
             choice = chunk["choices"][0]
-            citations = chunk.get("citations", [])
+
+            additional_kwargs = {}
+            if first_chunk:
+                additional_kwargs["citations"] = chunk.get("citations", [])
+                for attr in ["images", "related_questions"]:
+                    if attr in chunk:
+                        additional_kwargs[attr] = chunk[attr]
 
             chunk = self._convert_delta_to_message_chunk(
                 choice["delta"], default_chunk_class
             )
+
             if isinstance(chunk, AIMessageChunk) and usage_metadata:
                 chunk.usage_metadata = usage_metadata
+
             if first_chunk:
-                chunk.additional_kwargs |= {"citations": citations}
+                chunk.additional_kwargs |= additional_kwargs
                 first_chunk = False
+
             finish_reason = choice.get("finish_reason")
             generation_info = (
                 dict(finish_reason=finish_reason) if finish_reason is not None else None
@@ -386,9 +395,14 @@ class ChatPerplexity(BaseChatModel):
         else:
             usage_metadata = None
 
+        additional_kwargs = {"citations": response.citations}
+        for attr in ["images", "related_questions"]:
+            if hasattr(response, attr):
+                additional_kwargs[attr] = getattr(response, attr)
+
         message = AIMessage(
             content=response.choices[0].message.content,
-            additional_kwargs={"citations": response.citations},
+            additional_kwargs=additional_kwargs,
             usage_metadata=usage_metadata,
         )
         return ChatResult(generations=[ChatGeneration(message=message)])

libs/community/tests/unit_tests/chat_models/test_perplexity.py

@@ -116,3 +116,160 @@ def test_perplexity_stream_includes_citations(mocker: MockerFixture) -> None:
     assert full.additional_kwargs == {"citations": ["example.com", "example2.com"]}
 
     patcher.assert_called_once()
+
+
+@pytest.mark.requires("openai")
+def test_perplexity_stream_includes_citations_and_images(mocker: MockerFixture) -> None:
+    """Test that the stream method includes citations in the additional_kwargs."""
+    llm = ChatPerplexity(
+        model="test",
+        timeout=30,
+        verbose=True,
+    )
+    mock_chunk_0 = {
+        "choices": [
+            {
+                "delta": {
+                    "content": "Hello ",
+                },
+                "finish_reason": None,
+            }
+        ],
+        "citations": ["example.com", "example2.com"],
+        "images": [
+            {
+                "image_url": "mock_image_url",
+                "origin_url": "mock_origin_url",
+                "height": 100,
+                "width": 100,
+            }
+        ],
+    }
+    mock_chunk_1 = {
+        "choices": [
+            {
+                "delta": {
+                    "content": "Perplexity",
+                },
+                "finish_reason": None,
+            }
+        ],
+        "citations": ["example.com", "example2.com"],
+        "images": [
+            {
+                "image_url": "mock_image_url",
+                "origin_url": "mock_origin_url",
+                "height": 100,
+                "width": 100,
+            }
+        ],
+    }
+    mock_chunks: List[Dict[str, Any]] = [mock_chunk_0, mock_chunk_1]
+    mock_stream = MagicMock()
+    mock_stream.__iter__.return_value = mock_chunks
+    patcher = mocker.patch.object(
+        llm.client.chat.completions, "create", return_value=mock_stream
+    )
+    stream = llm.stream("Hello langchain")
+    full: Optional[BaseMessageChunk] = None
+    for i, chunk in enumerate(stream):
+        full = chunk if full is None else full + chunk
+        assert chunk.content == mock_chunks[i]["choices"][0]["delta"]["content"]
+        if i == 0:
+            assert chunk.additional_kwargs["citations"] == [
+                "example.com",
+                "example2.com",
+            ]
+            assert chunk.additional_kwargs["images"] == [
+                {
+                    "image_url": "mock_image_url",
+                    "origin_url": "mock_origin_url",
+                    "height": 100,
+                    "width": 100,
+                }
+            ]
+        else:
+            assert "citations" not in chunk.additional_kwargs
+            assert "images" not in chunk.additional_kwargs
+    assert isinstance(full, AIMessageChunk)
+    assert full.content == "Hello Perplexity"
+    assert full.additional_kwargs == {
+        "citations": ["example.com", "example2.com"],
+        "images": [
+            {
+                "image_url": "mock_image_url",
+                "origin_url": "mock_origin_url",
+                "height": 100,
+                "width": 100,
+            }
+        ],
+    }
+
+    patcher.assert_called_once()
+
+
+@pytest.mark.requires("openai")
+def test_perplexity_stream_includes_citations_and_related_questions(
+    mocker: MockerFixture,
+) -> None:
+    """Test that the stream method includes citations in the additional_kwargs."""
+    llm = ChatPerplexity(
+        model="test",
+        timeout=30,
+        verbose=True,
+    )
+    mock_chunk_0 = {
+        "choices": [
+            {
+                "delta": {
+                    "content": "Hello ",
+                },
+                "finish_reason": None,
+            }
+        ],
+        "citations": ["example.com", "example2.com"],
+        "related_questions": ["example_question_1", "example_question_2"],
+    }
+    mock_chunk_1 = {
+        "choices": [
+            {
+                "delta": {
+                    "content": "Perplexity",
+                },
+                "finish_reason": None,
+            }
+        ],
+        "citations": ["example.com", "example2.com"],
+        "related_questions": ["example_question_1", "example_question_2"],
+    }
+    mock_chunks: List[Dict[str, Any]] = [mock_chunk_0, mock_chunk_1]
+    mock_stream = MagicMock()
+    mock_stream.__iter__.return_value = mock_chunks
+    patcher = mocker.patch.object(
+        llm.client.chat.completions, "create", return_value=mock_stream
+    )
+    stream = llm.stream("Hello langchain")
+    full: Optional[BaseMessageChunk] = None
+    for i, chunk in enumerate(stream):
+        full = chunk if full is None else full + chunk
+        assert chunk.content == mock_chunks[i]["choices"][0]["delta"]["content"]
+        if i == 0:
+            assert chunk.additional_kwargs["citations"] == [
+                "example.com",
+                "example2.com",
+            ]
+            assert chunk.additional_kwargs["related_questions"] == [
+                "example_question_1",
+                "example_question_2",
+            ]
+        else:
+            assert "citations" not in chunk.additional_kwargs
+            assert "related_questions" not in chunk.additional_kwargs
+    assert isinstance(full, AIMessageChunk)
+    assert full.content == "Hello Perplexity"
+    assert full.additional_kwargs == {
+        "citations": ["example.com", "example2.com"],
+        "related_questions": ["example_question_1", "example_question_2"],
+    }
+
+    patcher.assert_called_once()

libs/community/uv.lock

@@ -1,4 +1,5 @@
 version = 1
+revision = 1
 requires-python = ">=3.9, <4.0"
 resolution-markers = [
     "python_full_version >= '3.12.4' and platform_python_implementation == 'PyPy'",
@@ -1531,6 +1532,7 @@ requires-dist = [
     { name = "requests", specifier = ">=2,<3" },
     { name = "sqlalchemy", specifier = ">=1.4,<3" },
 ]
+provides-extras = ["community", "anthropic", "openai", "azure-ai", "cohere", "google-vertexai", "google-genai", "fireworks", "ollama", "together", "mistralai", "huggingface", "groq", "aws", "deepseek", "xai"]
 
 [package.metadata.requires-dev]
 codespell = [{ name = "codespell", specifier = ">=2.2.0,<3.0.0" }]
@@ -1745,7 +1747,7 @@ typing = [
 
 [[package]]
 name = "langchain-core"
-version = "0.3.45"
+version = "0.3.47"
 source = { editable = "../core" }
 dependencies = [
     { name = "jsonpatch" },
@@ -1803,7 +1805,7 @@ typing = [
 
 [[package]]
 name = "langchain-tests"
-version = "0.3.14"
+version = "0.3.15"
 source = { editable = "../standard-tests" }
 dependencies = [
     { name = "httpx" },