core[patch]: update dict prompt template (#30967)

Align with JS changes made in
langchain-ai/langchainjs#8043

Author: baskaryan

libs/community/tests/unit_tests/load/test_serializable.py

@@ -540,6 +540,12 @@
         "chat_models",
         "ChatSambaStudio",
     ),
+    ("langchain_core", "prompts", "message", "_DictMessagePromptTemplate"): (
+        "langchain_core",
+        "prompts",
+        "dict",
+        "DictPromptTemplate",
+    ),
 }
 
 # Needed for backwards compatibility for old versions of LangChain where things

libs/core/langchain_core/load/mapping.py

@@ -44,6 +44,7 @@
         MessagesPlaceholder,
         SystemMessagePromptTemplate,
     )
+    from langchain_core.prompts.dict import DictPromptTemplate
     from langchain_core.prompts.few_shot import (
         FewShotChatMessagePromptTemplate,
         FewShotPromptTemplate,
@@ -68,6 +69,7 @@
     "BasePromptTemplate",
     "ChatMessagePromptTemplate",
     "ChatPromptTemplate",
+    "DictPromptTemplate",
     "FewShotPromptTemplate",
     "FewShotPromptWithTemplates",
     "FewShotChatMessagePromptTemplate",
@@ -94,6 +96,7 @@
     "BaseChatPromptTemplate": "chat",
     "ChatMessagePromptTemplate": "chat",
     "ChatPromptTemplate": "chat",
+    "DictPromptTemplate": "dict",
     "HumanMessagePromptTemplate": "chat",
     "MessagesPlaceholder": "chat",
     "SystemMessagePromptTemplate": "chat",

libs/core/langchain_core/prompts/__init__.py

@@ -37,10 +37,10 @@
 from langchain_core.messages.base import get_msg_title_repr
 from langchain_core.prompt_values import ChatPromptValue, ImageURL, PromptValue
 from langchain_core.prompts.base import BasePromptTemplate
+from langchain_core.prompts.dict import DictPromptTemplate
 from langchain_core.prompts.image import ImagePromptTemplate
 from langchain_core.prompts.message import (
     BaseMessagePromptTemplate,
-    _DictMessagePromptTemplate,
 )
 from langchain_core.prompts.prompt import PromptTemplate
 from langchain_core.prompts.string import (
@@ -396,9 +396,7 @@ class _StringImageMessagePromptTemplate(BaseMessagePromptTemplate):
 
     prompt: Union[
         StringPromptTemplate,
-        list[
-            Union[StringPromptTemplate, ImagePromptTemplate, _DictMessagePromptTemplate]
-        ],
+        list[Union[StringPromptTemplate, ImagePromptTemplate, DictPromptTemplate]],
     ]
     """Prompt template."""
     additional_kwargs: dict = Field(default_factory=dict)
@@ -447,7 +445,12 @@ def from_template(
                 raise ValueError(msg)
             prompt = []
             for tmpl in template:
-                if isinstance(tmpl, str) or isinstance(tmpl, dict) and "text" in tmpl:
+                if (
+                    isinstance(tmpl, str)
+                    or isinstance(tmpl, dict)
+                    and "text" in tmpl
+                    and set(tmpl.keys()) <= {"type", "text"}
+                ):
                     if isinstance(tmpl, str):
                         text: str = tmpl
                     else:
@@ -457,7 +460,15 @@ def from_template(
                             text, template_format=template_format
                         )
                     )
-                elif isinstance(tmpl, dict) and "image_url" in tmpl:
+                elif (
+                    isinstance(tmpl, dict)
+                    and "image_url" in tmpl
+                    and set(tmpl.keys())
+                    <= {
+                        "type",
+                        "image_url",
+                    }
+                ):
                     img_template = cast("_ImageTemplateParam", tmpl)["image_url"]
                     input_variables = []
                     if isinstance(img_template, str):
@@ -503,7 +514,7 @@ def from_template(
                             "format."
                         )
                         raise ValueError(msg)
-                    data_template_obj = _DictMessagePromptTemplate(
+                    data_template_obj = DictPromptTemplate(
                         template=cast("dict[str, Any]", tmpl),
                         template_format=template_format,
                     )
@@ -592,7 +603,7 @@ def format(self, **kwargs: Any) -> BaseMessage:
             elif isinstance(prompt, ImagePromptTemplate):
                 formatted = prompt.format(**inputs)
                 content.append({"type": "image_url", "image_url": formatted})
-            elif isinstance(prompt, _DictMessagePromptTemplate):
+            elif isinstance(prompt, DictPromptTemplate):
                 formatted = prompt.format(**inputs)
                 content.append(formatted)
         return self._msg_class(
@@ -624,7 +635,7 @@ async def aformat(self, **kwargs: Any) -> BaseMessage:
             elif isinstance(prompt, ImagePromptTemplate):
                 formatted = await prompt.aformat(**inputs)
                 content.append({"type": "image_url", "image_url": formatted})
-            elif isinstance(prompt, _DictMessagePromptTemplate):
+            elif isinstance(prompt, DictPromptTemplate):
                 formatted = prompt.format(**inputs)
                 content.append(formatted)
         return self._msg_class(