Steps to reproduce
$ python pwb.py shell >>> s=pywikibot.Site('cs') >>> l='voy:Main page' >>> p=pywikibot.Page(s, l) >>> p.exists() # or p.isRedirectPage() or whatever similar Traceback (most recent call last): File "/home/pavel/pywikibot/pywikibot/page.py", line 5639, in parse newsite = self._site.interwiki(prefix) File "/home/pavel/pywikibot/pywikibot/site.py", line 977, in interwiki return self._interwikimap[prefix].site File "/home/pavel/pywikibot/pywikibot/site.py", line 723, in __getitem__ raise self._iw_sites[prefix].site File "/home/pavel/pywikibot/pywikibot/page.py", line 5639, in parse newsite = self._site.interwiki(prefix) File "/home/pavel/pywikibot/pywikibot/site.py", line 977, in interwiki return self._interwikimap[prefix].site File "/home/pavel/pywikibot/pywikibot/site.py", line 723, in __getitem__ raise self._iw_sites[prefix].site File "/home/pavel/pywikibot/pywikibot/page.py", line 5639, in parse newsite = self._site.interwiki(prefix) File "/home/pavel/pywikibot/pywikibot/site.py", line 977, in interwiki return self._interwikimap[prefix].site File "/home/pavel/pywikibot/pywikibot/site.py", line 723, in __getitem__ raise self._iw_sites[prefix].site File "/home/pavel/pywikibot/pywikibot/page.py", line 5639, in parse newsite = self._site.interwiki(prefix) File "/home/pavel/pywikibot/pywikibot/site.py", line 977, in interwiki return self._interwikimap[prefix].site File "/home/pavel/pywikibot/pywikibot/site.py", line 723, in __getitem__ raise self._iw_sites[prefix].site File "/home/pavel/pywikibot/pywikibot/page.py", line 5639, in parse newsite = self._site.interwiki(prefix) File "/home/pavel/pywikibot/pywikibot/site.py", line 977, in interwiki return self._interwikimap[prefix].site File "/home/pavel/pywikibot/pywikibot/site.py", line 723, in __getitem__ raise self._iw_sites[prefix].site File "/home/pavel/pywikibot/pywikibot/page.py", line 5639, in parse newsite = self._site.interwiki(prefix) File "/home/pavel/pywikibot/pywikibot/site.py", line 977, in interwiki return self._interwikimap[prefix].site File "/home/pavel/pywikibot/pywikibot/site.py", line 723, in __getitem__ raise self._iw_sites[prefix].site File "/home/pavel/pywikibot/pywikibot/page.py", line 5639, in parse newsite = self._site.interwiki(prefix) File "/home/pavel/pywikibot/pywikibot/site.py", line 977, in interwiki return self._interwikimap[prefix].site File "/home/pavel/pywikibot/pywikibot/site.py", line 723, in __getitem__ raise self._iw_sites[prefix].site File "/home/pavel/pywikibot/pywikibot/site.py", line 673, in site self._site = pywikibot.Site(url=self.url) File "/home/pavel/pywikibot/pywikibot/__init__.py", line 1235, in Site code, fam = _code_fam_from_url(url) File "/home/pavel/pywikibot/pywikibot/__init__.py", line 1192, in _code_fam_from_url raise SiteDefinitionError("Unknown URL '{0}'.".format(url)) pywikibot.exceptions.SiteDefinitionError: Unknown URL 'https://cs.wikivoyage.org/wiki/$1'. During handling of the above exception, another exception occurred: Traceback (most recent call last): File "<console>", line 1, in <module> File "/home/pavel/pywikibot/pywikibot/page.py", line 806, in exists return self.pageid > 0 File "/home/pavel/pywikibot/pywikibot/page.py", line 287, in pageid self.site.loadpageinfo(self) File "/home/pavel/pywikibot/pywikibot/page.py", line 222, in site return self._link.site File "/home/pavel/pywikibot/pywikibot/page.py", line 5735, in site self.parse() File "/home/pavel/pywikibot/pywikibot/page.py", line 5646, in parse .format(self._text, self._site, prefix, e)) pywikibot.exceptions.SiteDefinitionError: voy:Main page is not a local page on wikipedia:cs, and the interwiki prefix voy is not supported by Pywikibot! Unknown URL 'https://cs.wikivoyage.org/wiki/$1'.
Expected behavior
This should be handled by some skippable warning as you don't want your link-examination script be interrupted by a SiteDefinitionError
Configuration
Python 3.7.2, issue appeared on cswiki: {{Refn|Mantrou Wikicest je [[voy:Wikivoyage:Welcome,_Wikipedians#Style_differences|férovost]]}} in page cs:w:Nadace WIkimedia