Conditional imports and reportMissingImports

[bluss]

How to deal with conditional imports in a good way. This is a pretty common one: use tomllib when it's available (Python 3.11+) else depend on tomli.

basedpyright is configured to check Python 3.8+ compatibility but the development venv is installed with python 3.12. This seems to create a conflict (?), for example that tomli is required for Py 3.8 but it's not installed because the development environment doesn't need it. There is no venv configuration that does not cause unecessary

My best guesses from the pyright playground is that this issue exists there too.
I don't know what a solution looks like here. See the diagnostics below for a description of what happens.

Project dependencies:

dependencies = [
    "tomli>=2.0.1; python_version < '3.11'",
]

Configuration:

[tool.pyright]
pythonVersion = "3.8"
include = ["src"]
extraPaths = ["src"]
venvPath = "."
venv = ".venv"
exclude = [".venv"]
typeCheckingMode = "basic"

Development environment installation:

• venv python: 3.12. tomli not installed.
• (It's also possible to use: venv python: 3.8: tomli installed, tomllib not available.)

First version of the code:

try:
    import tomllib as tomli
except ImportError:
    import tomli as tomli

  try:                                                                                                                                                           
*     import tomllib as tomli                                                                                                                                    
             └──── reportMissingImports: Import "tomllib" could not be resolved                                                                                  
  except ImportError:                                                                                                                                            
*     import tomli as tomli                                                                                                                                      
             └──── reportMissingImports: Import "tomli" could not be resolved

Alternative version of the code:

if sys.version_info >= (3, 11):
    import tomllib as tomli
else:
    import tomli as tomli

  if sys.version_info >= (3, 11):                                                                                                                                
      import tomllib as tomli                                                                                                                                    
      └──── reportUnreachable: Code is unreachable                                                                                                               
  else:                                                                                                                                                          
*     import tomli as tomli                                                                                                                                      
             └──── reportMissingImports: Import "tomli" could not be resolved

basedpyright --version
basedpyright 1.17.5
based on pyright 1.1.381

[DetachHead]

merging with #8 as i believe that would solve this issue

[bluss]

Thanks for the work on basedpyright!