make linkcheck wrongly reports valid anchors as broken for certain links

[mara004]

Description
make linkcheck reports certain links with anchor would be broken, altough they are not.
Example: https://framagit.org/peppercarrot/wiki/-/blob/master/Creatures.md#phanda

Steps to Reproduce

• initialise a new documentation via sphinx-quickstart
• create a file with the aforementioned link connected to index.rst
• run make linkcheck

(...)    broken    https://framagit.org/peppercarrot/wiki/-/blob/master/Creatures.md#phanda - Anchor 'phanda' not found

Expected behavior
The link is valid and works from the browser, hence it should be reported as ok rather than broken

Environment info

• OS: KDE Neon User 5.21.5 (Linux)
• Python version: 3.8.5
• Sphinx version: 3.5.3
• Extra tools: Chromium M90

→ Potential duplicate of #9016

[mara004]

As the discussion on #9016 suggests, this is hard to fix. Would it be possible to rather report not-found anchors as partly ok or something like this as a workaround?

[bskinn]

Concur, having not-found anchors report as a warning, instead of a hard error, would be useful for me, too.

Adding a config/CLI option to convert these linkcheck warnings to errors would be a nice feature also.

[tk0miya]

It seems the HTML returned from https://framagit.org/peppercarrot/wiki/-/blob/master/Creatures.md does not contains #phanda anchor.

$ curl -s -o - -L https://framagit.org/peppercarrot/wiki/-/blob/master/Creatures.md | grep phanda
$ 

I can't find any content in the .md file also.

$ curl -s -o - -L https://framagit.org/peppercarrot/wiki/-/blob/master/Creatures.md | grep "Argiope Spiders"
$ 
$ curl -s -o - -L https://framagit.org/peppercarrot/wiki/-/blob/master/Creatures.md | grep "DragonCow"
$ 

I guess the whole of the content is lazily rendered by JavaScript. Surely this is similar to #9016. So I feel this is also difficult to resolve.

How about using linkcheck_anchors_ignore? In this case, the above link is considered as "working" with this setting:

linkcheck_anchors_ignore = ['phanda']