1253865 - Unresolvable www subdomain unexpectedly redirects to domain without www

Status: RESOLVED INVALID

(Firefox :: Address Bar, defect, P3)

Description

[rugk]

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:44.0) Gecko/20100101 Firefox/44.0
Build ID: 20160210153822

Steps to reproduce:

Access gesetze-im-internet.de.


Actual results:

Firefox loads http://www.gesetze-im-internet.de/. However in the console no request to "http://gesetze-im-internet.de/" is shown as if I have never accessed/tried to access gesetze-im-internet.de.


Expected results:

There should be a connection error ("Could not resolve host" or similar).
This is the behaviour of tools like curl and also Chromium shows an error.

This issue was discovered in https://github.com/EFForg/https-everywhere/pull/4266 and there you may also see more information.
Note: In Tor Browser (Firefox/38.0 ESR) it fails, which is the correct behaviour.

Comment 1

[rugk]

BTW the STR is not completely correct: You access https://gesetze-im-internet.de, so no autocompletion sho0uld take place.

Comment 2

[Brian Grinstead [:bgrins]]

Based on the title / description I believe the request here is that the browser shows an error page when 'gesetze-im-internet.de' in the URL bar. Chrome shows a DNS error, but Firefox loads 'http://www.gesetze-im-internet.de/'.  Needinfo to the reporter to confirm this is the case.

I'm assuming the location bar is somehow sanitizing / changing the input, so moving back into Location Bar component.

Comment 3

[rugk]

Yes that's the issue.

Comment 4

[Marco Bonardo [:mak] (Away Apr 25 - May 5)]

it's URIFixup that adds the www. (or better, it adds browser.fixup.alternate.prefix)
I don't know if currently it's done on purpose, it needs to be investigated.

Comment 5

[rugk]

So what exactly should I tell you? 
I have no idea whether that's done on purpose or not.

Comment 6

[Brian Grinstead [:bgrins]]

Clearing needinfo based on Comment 5

Comment 7

[Marco Bonardo [:mak] (Away Apr 25 - May 5)]

ehr sorry, I didn't mean to set that needinfo.

Comment 8

[rugk]

Uhh, this is old. Anyone?

Comment 9

[Marco Bonardo [:mak] (Away Apr 25 - May 5)]

This is done on purpose, when a domain doesn't resolve the docshell tries to add browser.fixup.alternate.prefix to it and loads that. The pref can be changed to an empty string I think.
Not a bug by itself, since it's the expected behavior.