Recently the welcome script failed on Travis: https://travis-ci.org/wikimedia/pywikibot-core/jobs/58246884#L756 As that output is a bit unwieldy here is the output easier to read:
```
[NoAct] ***Ahmed abssi has no contributions.
[Match] ***Brahhhimm has enough edits to be welcomed.
WARNING: /home/travis/build/wikimedia/pywikibot-core/pywikibot/family.py:916: FamilyMaintenanceWarning: Family name wikimediachapter does not match family module name wikimedia
SIMULATION: edit action blocked. ***
Page [[ÙÙاش اÙÙ
ستخدÙ
:Brahhhimm]] saved
[Done ] ***One user has been welcomed.
[NoAct] ***Hosnymansor has no contributions.
[NoAct] ***Bilal chafi has no contributions.
[NoAct] ***Ridouan al hannachi has no contributions.
[NoAct] ***Techno oussama has no contributions.
[NoAct] ***سÙÙ
ا٠عبداÙرØÙ
Ù Ù
Ùس٠خبش has no contributions.
[NoAct] ***Ø£ØÙ
د عاÙ
ر اÙÙ
طارÙØ© has no contributions.
[NoAct] ***ÙÙÙÙ 000 has no contributions.
[NoAct] ***Djoukeng Borel has no contributions.
[NoAct] ***ArameaWiki has no contributions.
[NoAct] ***Mjno0onk has no contributions.
[NoAct] ***Abdulrmomin has no contributions.
[NoAct] ***Amdsab has no contributions.
[NoAct] ***WINNERS05 has no contributions.
[NoAct] ***Super-hicham has no contributions.
[NoAct] ***Badr salhi has no contributions.
[NoAct] ***Amin osx has no contributions.
[NoAct] ***Mohamed tahirii has no contributions.
[NoAct] ***Sami almadhgi has no contributions.
[NoAct] ***Wildtunis has no contributions.
[Match] ***Achway has enough edits to be welcomed.
[Skip ] ***Achway has been already welcomed.
[NoAct] ***Anas x-love has no contributions.
[NoAct] ***Cloracefmr has no contributions.
[NoAct] ***Hamza halhoul has no contributions.
[NoAct] ***Osama Alzoubi has no contributions.
[NoAct] ***Ayoub malloul has no contributions.
[NoAct] ***Turki althakafi has no contributions.
[NoAct] ***7assiba has no contributions.
[NoAct] ***El Ouakili has no contributions.
[NoAct] ***TAREQ ESAM HAMMAD has no contributions.
[NoAct] ***Jin dido has no contributions.
[NoAct] ***Argentumbolo has no contributions.
[NoAct] ***I'm so meta even this acronym has no contributions.
[NoAct] ***Ikmalsyafiq has no contributions.
[NoAct] ***Talal RH has no contributions.
[NoAct] ***ابÙاÙاد5886 has no contributions.
[NoAct] ***Malobaid has no contributions.
[Match] ***John Vandenberg has enough edits to be welcomed.
[Skip ] ***John Vandenberg has been already welcomed.
[NoAct] ***XZise has no contributions.
[NoAct] ***MZERYOH has no contributions.
[NoAct] ***Aboomara1972 has no contributions.
[NoAct] ***Wå Lîî Døx has no contributions.
[NoAct] ***Ejs-80 has no contributions.
[NoAct] ***Luke081515 has no contributions.
[NoAct] ***سÙ
٠اÙبدر 502 has no contributions.
[NoAct] ***MjdBashrahel has no contributions.
[NoAct] ***Mohammed fanatsah has no contributions.
[Skip ] ***دائرة اÙÙ
عار٠اÙÙاÙÙÙÙØ© has been blocked!
[NoAct] ***Latifa iman has no contributions.
[MSG ] ***Putting the log of the latest user...
[MSG ] ***Log page is not exist, getting information for page creation
Traceback (most recent call last):
File "/home/travis/build/wikimedia/pywikibot-core/pwb.py", line 215, in <module>
run_python_file(filename, argv, argvu, file_package)
File "/home/travis/build/wikimedia/pywikibot-core/pwb.py", line 84, in run_python_file
main_mod.__dict__)
File "./scripts/welcome.py", line 1017, in <module>
main()
File "./scripts/welcome.py", line 998, in main
bot.run()
File "./scripts/welcome.py", line 831, in run
if self.makelogpage(self.welcomed_users):
File "./scripts/welcome.py", line 661, in makelogpage
text += u'\n!%s' % self.site.namespace(2)
TypeError: unsupported operand type(s) for +=: 'NoneType' and 'unicode'
CRITICAL: Waiting for 1 network thread(s) to finish. Press ctrl-c to abort
```
So text is None and looking into the code reveals that it translates it using the site's language and a fixed logpage_header table.
text = i18n.translate(self.site, logpage_header)
text += u'\n!%s' % self.site.namespace(2)
And logpage_header has only the keys `_default`, `no` and `it` and without `fallback` set to `True` it won't use `_default`. Interestingly I can't find any recent changes that would've lead to this problem (e.g. `fallback` parameter removed).