Fix metadata-up-to-date lint script

[simondeziel]

The script would abort when a delta between "before" and "after" was noticed because diff would return with a non-0 code. Fix that so that we can see the delta if there is one and use "unified" mode.

[simondeziel]

@ru-fu it seems this link is sometimes returning a 403:

2023-09-06T18:03:22.4520974Z ( doc-cheat-sheet: line  368) broken    https://docutils.sourceforge.io/docs/ref/rst/directives.html#list-table - 403 Client Error: Forbidden for url: https://docutils.sourceforge.io/docs/ref/rst/directives.html

Which is easy enough to trigger:

$ for i in $(seq 10); do wget -qSO /dev/null https://docutils.sourceforge.io/docs/ref/rst/directives.html#list-table 2>&1 | head -n1; done
  HTTP/1.1 200 OK
  HTTP/1.1 200 OK
  HTTP/1.1 200 OK
  HTTP/1.1 403 Forbidden
  HTTP/1.1 200 OK
  HTTP/1.1 200 OK
  HTTP/1.1 200 OK
  HTTP/1.1 200 OK
  HTTP/1.1 200 OK
  HTTP/1.1 200 OK

Is there an exclusion mechanism we can use to ignore it?

[ru-fu]

it seems this link is sometimes returning a 403:

I've never seen that before - maybe it was just flaky yesterday when you tested?
Or have you seen it before?

[simondeziel]

I can't get the 403 today so it probably was a one off. As such, I dropped all the link checker changes from the PR. Thanks @ru-fu!

[simondeziel]

Hmm, this time it's not a 403 but a TLS handshake failure:

( doc-cheat-sheet: line  368) broken    https://docutils.sourceforge.io/docs/ref/rst/directives.html#list-table - HTTPSConnectionPool(host='docutils.sourceforge.io', port=443): Max retries exceeded with url: /docs/ref/rst/directives.html (Caused by SSLError(SSLError(1, '[SSL: SSLV3_ALERT_HANDSHAKE_FAILURE] sslv3 alert handshake failure (_ssl.c:1007)')))

And it's not just us apparently: https://www.ssllabs.com/ssltest/analyze.html?d=docutils.sourceforge.io#12098

If the doc is available from another source, maybe we should switch.

[ru-fu]

If the doc is available from another source, maybe we should switch.

Hmm, this is the main source for it, I would be surprised if it was available somewhere else.
Let's keep an eye on it.