Can't figure out "unknown import symbol"

[ronf]

I have some code for which pyright is reporting an "unknown import symbol" in a third-party library that I can't figure out. It also involves conditional imports, and I found issue #1358 and tried to use TYPE_CHECKING to control which version of an import was included, and that solved another issue I was having. However, pyright is now returning an "unknown import symbol" error that I can't seem to avoid.

I've stripped down the code to a bare minimum (just class declarations and imports) and I'm still able to reproduce the problem. I've got a base module and two platform-specific modules (unix and win32), plug a try...except meant to cover when the third-party library is not installed. It currently looks something like:

gss.py:

import sys

from typing import TYPE_CHECKING


try:
    if sys.platform == 'win32':
        from .gss_win32 import GSSBase, GSSClient, GSSServer, GSSError
    else:
        from .gss_unix import GSSBase, GSSClient, GSSServer, GSSError

    gss_available = True
except ImportError:
    gss_available = False


if not TYPE_CHECKING:
    class GSSError(ValueError):
        """Stub class for reporting that GSS is not available"""

    class GSSBase:
        """Base class for reporting that GSS is not available"""

    class GSSClient(GSSBase):
        """Stub client class for reporting that GSS is not available"""

    class GSSServer(GSSBase):
        """Stub client class for reporting that GSS is not available"""

gss_unix.py:

from gssapi.exceptions import GSSError


class GSSBase:
    """GSS base class"""

class GSSClient(GSSBase):
    """GSS client"""

class GSSServer(GSSBase):
    """GSS server"""

gss_win32.py:

class GSSBase:
    """GSS base class"""

class GSSClient(GSSBase):
    """GSS client"""

class GSSServer(GSSBase):
    """GSS server"""

class GSSError(Exception):
    """Class for reporting GSS errors"""

The error I'm getting is:

npx: installed 1 in 1.284s
No configuration file found.
No pyproject.toml file found.
stubPath /private/tmp/typings is not a valid directory.
Assuming Python platform Darwin
Searching for source files
File or directory "/private/tmp/--" does not exist.
Found 3 source files
/tmp/gss.py
  /tmp/gss.py:10:62 - error: "GSSError" is unknown import symbol (reportGeneralTypeIssues)
1 error, 0 warnings, 0 infos
Completed in 0.521sec

I've also tried replacing the GSSError import in gss_unix.py with from gssapi.exceptions import GSSError as GSSError in case this was some kind of re-export issue, but that didn't make a difference. The code runs fine, and "mypy" is also happy with it, but I can't figure out how to make "pyright" happy with it.

If it matters, the system I'm running this on has the gssapi package installed, and so the import from gss_unix.py should be succeeding and getting the definition of GSSError from gssapi.exceptions. I just noticed that GSSError appears to be defined in a C module in that package, so perhaps that's related.

Without providing my own stubs for this module, is there some way I can silence this error? I'm fine if there's no type checking related to this class.

[erictraut]

Thanks for posting. This is a bug in pyright's import resolution logic. In particular, it's related to the case where a chain of imports (where one module imports a symbol from another module, which imports it from another module, etc.) ends in a native library (a ".pyd" or ".so" binary file). Pyright should resolve this without errors and supply an "Unknown" type for the symbol. This will be fixed in the next release.

[ronf]

Interesting - thanks for taking a look so quickly! I look forward to the fix..

[mchccc]

Hello, sorry for digging this out but I'm still seeing this when importing a function from cytoolz, which indeed ends up in a .pxd/.pyx file.. Was this eventually fixed? And if so, what could I be doing wrong to still be seeing it?