How can I pass custom config from pyproject.toml to custom build hook?

[james-oldfield-inex]

I'd like to be able to set a value in pyproject.toml that can later be used by the custom build hook. So it would be set like this:

# Section in pyproject.toml
[tool.hatch.build.hooks.custom]
path = "my_build_hook.py"
myconfig = "xyz"

Then inside my_build_hook.py:

from hatchling.builders.hooks.plugin.interface import BuildHookInterface

class CustomBuildHook(BuildHookInterface):
    def initialize(self, version, build_data):
        super().initialize(version, build_data)
        print(self.get_config_somehow("myconfig"))  # prints "xyz"

Is this possible somehow? I realise that I could just make myconfig a global constant in the build hook Python file, but I have something that I imagine will change with each release while the rest of the code of the hook won't, so it would be more elegant if it were in the pyproject.toml file instead.

Looking at the source code to CustomBuildHook (in hatch/backend/src/hatchling/builders/hooks/custom.py), it looks like this would work:

class CustomBuildHook(BuildHookInterface):
    def __init__(self, root, config, *args, **kwargs):
        self.myconfig = config["myconfig"]  # Saves xyz in self.myconfig

But I don't see it documented anywhere so I don't know if this is guaranteed to be a stable API.

[james-oldfield-inex]

Ah, I think it might be as simple as BuildHookInterface.config:

class CustomBuildHook(BuildHookInterface):
    def initialize(self, version, build_data):
        print(self.config["myconfig"])