Use structural pattern matching to handle linkcheck result statuses

[jayaddison]

Feature or Bugfix

• Refactoring (and a legacy code cleanup)

Purpose

• The repeated [el]if...result.status == <status> conditions in part of the linkcheck code expose an intended behaviour: each status code implies that the code should follow one particular code path to handle the result. This seems like a good fit for a match clause, available from Python3.11+.

Detail

• Handle linkcheck status codes using a match statement.
• Also includes a tangential refactor of some logging code, to fit the resulting code within formatting guidelines while remaining aesthetically reasonable.
• For review purposes, it could be helpful to ignore whitespace differences introduced by this changeset (w=1 query-string parameter, if using the GitHub web comparison interface).

Relates

• Builds upon Use a StrEnum to record linkcheck status codes #13043.

[AA-Turner]

Can we integrate the UNCHECKED and WORKING (old) checks above into the match? Ideally, as we use an enum, we shouldn't need to use case _ -- we just check every valid state.

A

[jayaddison]

Commenting for future historians: the old message tag here was a way that the linkcheck component would communicate to itself that a hyperlink had already been checked and confirmed as working ('good').

That code was removed in 4351721, and I believe that the URI deduplication that was removed there is no longer necessary, because linkcheck nowadays collects hyperlinks in a Python dict, CheckExternalLinksBuilder.hyperlinks, keyed by the URI; so duplicates should not occur anyway.

[jayaddison]

@AA-Turner changelog entry required, do you think?

[AA-Turner]

There's no visible behaviour change to users so I shouldn't think one is required.

[AA-Turner]

Thank you @jayaddison!

A

[jayaddison]

Brilliant! Thank you for the code reviews!

[AA-Turner]

It seems 'local' is currently unused, by the way.

[jayaddison]

Mmm. As is the linkstat['text'] assignment.

For local -- perhaps that should become part of a separate link property that indicates whether each link is local or remote. I'll think about that and file a change suggestion / feature description at some point.