Issue Details

LocalPackageInfo doesn't find licenses defined with License-Expression.

Description

I noticed this when checking a package playwright where no license was found. On inspection it would appear that the wrong string is used when searching for License-Expression (License_Expression is used). It should be a hyphen as per PEP-639.

Why did i notice it? It appears playwright has an issue in the json metadata on the latest version and the license cannot be found on remote either (which is the fallback) - https://pypi.org/pypi/playwright/1.52.0/json

	def get_license(self) -> str | None:
		return (
			meta_get(self.meta, "License_Expression")
			or from_classifiers(self.meta.get_all("Classifier"))
			or meta_get(self.meta, "License")
		)

Expected Behavior

License-Expression should be found in metadata

Actual Behavior

No License found (this happens for all PEP-639 packages except it is normally silent due to the remote fallback

System Information

environment:Python 3.10.12

• Operating System (OS): Ubuntu
• OS Version: 22.04