[feature] add `self.*_path` properties that return `pathlib.Path`

• I’ve read the CONTRIBUTING guide.

We have recipe_folder, source_folder, etc that return Optional[str].

It would be nice to work with filesystem paths using pathlib.Path.

As the *_folder can be None in certain stages, it is usually a programming error accessing them when they are None.

It would be nice to have the following accessors on the ConanFile:

    @property
    def package_path(self) -> Path:
        """
        :returns: The location of the final packaging location              
        """
        assert self.package_folder is not None, "`package_folder` is `None`"
        return Path(self.package_folder)

Then we can use it like so:

    def build(self) -> None:
        exe = self.package_path / "bin" / "hello-world"
        exe.parent.mkdir()
        with exe.open(encoding="utf8") as stream:
            stream.write("#! /bin/sh\necho 'Hello, world!'')
        exe.chmod(0o755)

Which is much nicer that the equivalent code with os.path.

[SSE4]

here we go: #11585

[memsharded]

The problem with this is that Conan 1.X still supports Python 2.7 (sigh, I know…), so this couldn’t be added. Then we need to keep the current xxx_folder as strings for the Conan 1.X -> Conan 2.0 migration.

We will probably start to use Pathlib gradually at Conan 2.X (once the migration cliff has been surpassed), and from there we might be able to consider this request.