[issue43926] Clean metadata (importlib_metadata 4.0)

[Jason R. Coombs]

New submission from Jason R. Coombs <jaraco at jaraco.com>:

[importlib_metadata 4.0](https://importlib-metadata.readthedocs.io/en/latest/history.html#v4-0-0) introduced these important changes to the `metadata` function:

``PackageMetadata`` as returned by ``metadata()``
  and ``Distribution.metadata()`` now provides normalized
  metadata honoring PEP 566:

  - If a long description is provided in the payload of the
    RFC 822 value, it can be retrieved as the ``Description``
    field.
  - Any multi-line values in the metadata will be returned as
    such.
  - For any multi-line values, line continuation characters
    are removed. This backward-incompatible change means
    that any projects relying on the RFC 822 line continuation
    characters being present must be tolerant to them having
    been removed.
  - Add a ``json`` property that provides the metadata
    converted to a JSON-compatible form per PEP 566.

These changes would be a nice addition to Python 3.10.

----------
assignee: jaraco
components: Library (Lib)
messages: 391733
nosy: jaraco
priority: normal
severity: normal
status: open
title: Clean metadata (importlib_metadata 4.0)
type: enhancement
versions: Python 3.10

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue43926>
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