Repository: langchain
Issue: PydanticUserError for OpenAI LLMs
Labels: Ɑ:  core

### Checked other resources

- [X] I added a very descriptive title to this issue.
- [X] I searched the LangChain documentation with the integrated search.
- [X] I used the GitHub search to find a similar question and didn't find it.
- [X] I am sure that this is a bug in LangChain rather than my code.
- [X] The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package).

### Example Code

llm = OpenAI(
    api_key=settings.openai_api_key,
    verbose=True,
    temperature=0,
    model_name="gpt-4",
)
llm.invoke("....")

### Error Message and Stack Trace (if applicable)

pydantic.errors.PydanticUserError: If you use `@root_validator` with pre=False (the default) you MUST specify `skip_on_failure=True`. Note that `@root_validator` is deprecated and should be replaced with `@model_validator`.

For further information visit https://errors.pydantic.dev/2.9/u/root-validator-pre-skip


### Description

I am really unhappy with this library. Let me put it that way. Using this library is really questioning my potential as a developer!
Whenever I start a new task with this library, I run into some import statement issues, some pydantic errors, and what not!
One day, I need to import PromptTemplate from langchain.prompts, the next day I have to import it from langchain_core.prompts. The documentation is not at all helpful with these changes. 

With that Rant, let me explain my issue, and eventually the bot will give the same answer to downgrade my pydantic version. But still I will try to explain

I am trying to use the invoke method in the OpenAI instance, and getting a PydanticUserError. The code and the error message is attached below.

### System Info

alembic==1.13.3
amqp==5.2.0
annotated-types==0.7.0
anyio==4.6.0
astroid==3.3.5
billiard==4.2.1
black==24.10.0
boto3==1.35.37
botocore==1.35.37
celery==5.4.0
certifi==2024.8.30
cfgv==3.4.0
charset-normalizer==3.4.0
click==8.1.7
click-didyoumean==0.3.1
click-plugins==1.1.1
click-repl==0.3.0
colorama==0.4.6
dill==0.3.9
distlib==0.3.9
distro==1.9.0
dnspython==2.7.0
ecdsa==0.19.0
email_validator==2.2.0
fastapi==0.115.0
fastapi-cli==0.0.5
filelock==3.16.1
flake8==7.1.1
flower==2.0.1
greenlet==3.1.1
h11==0.14.0
httpcore==1.0.6
httptools==0.6.1
httpx==0.27.2
humanize==4.11.0
identify==2.6.1
idna==3.10
isort==5.13.2
Jinja2==3.1.4
jiter==0.6.1
jmespath==1.0.1
jose==1.0.0
jsonpatch==1.33
jsonpointer==3.0.0
kombu==5.4.2
langchain==0.0.27
langchain-core==0.3.13
langchain-openai==0.2.2
langsmith==0.1.137
Mako==1.3.5
markdown-it-py==3.0.0
MarkupSafe==3.0.1
mccabe==0.7.0
mdurl==0.1.2
mypy-extensions==1.0.0
nodeenv==1.9.1
numpy==2.1.2
openai==1.51.2
orjson==3.10.10
packaging==24.1
pandas==2.2.3
pathspec==0.12.1
pika==1.3.2
pipenv==2024.1.0
platformdirs==4.3.6
pre_commit==4.0.1
prometheus_client==0.21.0
prompt_toolkit==3.0.48
psycopg2==2.9.9
pyasn1==0.6.1
pycodestyle==2.12.1
pydantic==2.9.2
pydantic-settings==2.6.0
pydantic_core==2.23.4
pyflakes==3.2.0
Pygments==2.18.0
pylint==3.3.1
python-dateutil==2.9.0.post0
python-dotenv==1.0.1
python-jose==3.3.0
python-multipart==0.0.12
pytz==2024.2
PyYAML==6.0.2
regex==2024.9.11
requests==2.32.3
requests-toolbelt==1.0.0
rich==13.9.2
rsa==4.9
s3transfer==0.10.3
setuptools==75.1.0
shellingham==1.5.4
six==1.16.0
sniffio==1.3.1
SQLAlchemy==2.0.35
sqlmodel==0.0.22
starlette==0.38.6
tenacity==9.0.0
tiktoken==0.8.0
tomlkit==0.13.2
tornado==6.4.1
tqdm==4.66.5
typer==0.12.5
typing_extensions==4.12.2
tzdata==2024.2
urllib3==2.2.3
uvicorn==0.31.0
vine==5.1.0
virtualenv==20.27.0
watchfiles==0.24.0
wcwidth==0.2.13
websockets==13.1