Python relative imports?

[khteh]

I have code like the following:

from .State import CustomAgentState
from .image import show_graph

Running it with langgraph dev hits an error:

  File "/usr/src/Python/rag-agent/src/rag_agent/RAGAgent.py", line 3, in <module>
    from .State import CustomAgentState
ImportError: attempted relative import with no known parent package
Could not import python module for graph:
GraphSpec(id='rag_agent', path='./src/rag_agent/RAGAgent.py', module=None, variable='make_graph', config=None)
This error likely means you haven't installed your project and its dependencies yet. Before running the server, install your project:

How to use relative import with langgraph dev?

System Info

langchain==0.3.20
langchain-community==0.3.19
langchain-core==0.3.45
langchain-google-genai==2.1.0
langchain-google-vertexai==2.0.9
langchain-openai==0.3.8
langchain-text-splitters==0.3.6

[HassanAtWecrunch]

make sure you`re doing this

ENV PYTHONPATH=/app/src

[null-ed]

@HassanAtWecrunch @khteh

I'm encountering the exact same issue. I tried setting PYTHONPATH=/src or PYTHONPATH=. in my .env file, but neither solved the problem.
My project structure:

my_project
  |--src
  |   |--agent
  |       |--graph.py
  |       |--test_module.py
  |--.env
  |--langgraph.json
  |--pyproject.toml

graph.py

from .test_module import name

test_module.py

name="test_module"

.env

# To separate your traces from other application
LANGSMITH_PROJECT=new-agent

# Add API keys for connecting to LLM providers, data sources, and other integrations here
LANGSMITH_API_KEY="lsv2_xxxxxxxxxx"

#None of these settings resolved the issue
#PYTHONPATH=/src
#PYTHONPATH=./src/ 
#PYTHONPATH=./  
PYTHONPATH=.

langgraph.json

{
  "dependencies": ["."],
  "graphs": {
    "agent": "./src/agent/graph.py:graph"
  },
  "env": ".env",
  "image_distro": "wolfi"
}

langgraph dev Error

    from .test_module import name
ImportError: attempted relative import with no known parent package
Could not import python module for graph:
GraphSpec(id='agent', path='./src/agent/graph.py', module=None, variable='graph', config={}, description=None)
This error likely means you haven't installed your project and its dependencies yet. Before running the server, install your project:

If you are using requirements.txt:
python -m pip install -r requirements.txt

If you are using pyproject.toml or setuptools:
python -m pip install -e .

Make sure to run this command from your project's root directory (where your setup.py or pyproject.toml is located)

[khteh]

For your case, I believe you have missing __init__.py file.

[null-ed]

this approach does not solve the problem

my_project
  |--__init__.py
  |--src
  |   |--__init__.py
  |   |--agent
  |       |--__init__.py
  |       |--graph.py
  |       |--test_module.py
  |--.env
  |--langgraph.json
  |--pyproject.toml