PDM_BUILD_NO_CLEAN handling doesn't seem right

[genericmoniker]

In Builder.clean (source), there is this if statement:

        if (
            not self.config_settings.get("no-clean-build")
            or os.getenv("PDM_BUILD_NO_CLEAN", "false").lower() != "false"
        ):
            self.clean(context)

The double-negatives pinch my brain a bit, but it seems like != "false" should be == "false".

If I want the build directory to not be cleaned I would set:

PDM_BUILD_NO_CLEAN=true

As the code is, "true" != "false" evaluates to True and self.clean(context) is called.