pallets/flask · error · RuntimeError

No root path can be found for the provided module {import_na

Error message

No root path can be found for the provided module {import_name!r}. This can happen because the module came from an import hook that does not provide file name information or because it's a namespace package. In this case the root path needs to be explicitly provided.

What it means

Flask(import_name) resolves the application's root_path by importing the named module and reading its __file__ so it can locate templates, static files, and instance folders. Namespace packages (PEP 420) and modules created by import hooks have no __file__, so get_root_path cannot derive a filesystem location and raises RuntimeError telling you to supply it explicitly.

Source

Thrown at src/flask/helpers.py:631

    # Loader does not exist or we're referring to an unloaded main
    # module or a main module without path (interactive sessions), go
    # with the current working directory.
    if loader is None:
        return os.getcwd()

    if hasattr(loader, "get_filename"):
        filepath = loader.get_filename(import_name)  # pyright: ignore
    else:
        # Fall back to imports.
        __import__(import_name)
        mod = sys.modules[import_name]
        filepath = getattr(mod, "__file__", None)

        # If we don't have a file path it might be because it is a
        # namespace package. In this case pick the root path from the
        # first module that is contained in the package.
        if filepath is None:
            raise RuntimeError(
                "No root path can be found for the provided module"
                f" {import_name!r}. This can happen because the module"
                " came from an import hook that does not provide file"
                " name information or because it's a namespace package."
                " In this case the root path needs to be explicitly"
                " provided."
            )

    # filepath is import_name.py for a module, or __init__.py for a package.
    return os.path.dirname(os.path.abspath(filepath))  # type: ignore[no-any-return]


@cache
def _split_blueprint_path(name: str) -> list[str]:
    out: list[str] = [name]

    if "." in name:
        out.extend(_split_blueprint_path(name.rpartition(".")[0]))

View on GitHub ↗ (pinned to 6a2f545bfd)

Solutions

1. Pass root_path explicitly: Flask(__name__, root_path=os.path.dirname(os.path.abspath(__file__))).
2. Add an __init__.py to the package so it becomes a regular package with __file__.
3. Use the concrete module's __name__ (Flask(__name__)) from a real .py file instead of a namespace package name.
4. In frozen apps, compute the bundle path (e.g. sys._MEIPASS for PyInstaller) and pass it as root_path.

Example fix

# before
app = Flask('company')  # 'company' is a namespace package
# after
import os
app = Flask(__name__, root_path=os.path.dirname(os.path.abspath(__file__)))

import importlib.util, os
spec = importlib.util.find_spec(import_name)
has_file = spec is not None and spec.origin not in (None, 'namespace')
root = os.path.dirname(os.path.abspath(spec.origin)) if has_file else os.getcwd()
app = Flask(import_name, root_path=root)

import importlib.util
def module_has_root_path(import_name: str) -> bool:
    spec = importlib.util.find_spec(import_name)
    return spec is not None and spec.origin not in (None, 'namespace')

When it happens

Trigger: Flask('mypkg') where mypkg is a namespace package (a directory with no __init__.py, or a package split across multiple dirs); import_name pointing at a module loaded from a zip/frozen bundle or custom finder whose loader lacks get_filename and the module lacks __file__.

Common situations: Forgetting __init__.py in a src-layout package; PyInstaller/zipapp/frozen deployments; monorepos using implicit namespace packages for shared roots; passing a top-level namespace like 'company' instead of the concrete subpackage.

Related errors

• Working outside of application context. Attempted to use fu
• Working outside of request context. Attempted to use functi
• The session is unavailable because no secret key was set. S
• The environment variable {variable_name!r} is not set and as
• 'after_this_request' can only be used when a request context

AI-assisted analysis of pallets/flask@6a2f545bfd (2026-07-31). Data as JSON: /data/errors/8fddface7b8aa965.json. Report an issue: GitHub ↗.