webbrowser module broken with Firefox 36+

[ssokolow]

BPO	23262
Nosy	@phdru, @ssokolow, @ezio-melotti, @lilydjwg, @berkerpeksag, @serhiy-storchaka, @wyz23x2, @Syaifulnizamshamsudin
Files	webbrowser.py-3.5.patch webbrowser.py-3.5.patch: Regenerated for review webbrowser.py-3.5-2.patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2021-10-12.14:20:03.194>
created_at = <Date 2015-01-18.04:16:56.445>
labels = ['3.7', 'type-bug', 'library']
title = 'webbrowser module broken with Firefox 36+'
updated_at = <Date 2021-10-12.14:20:03.192>
user = 'https://github.com/ssokolow'

bugs.python.org fields:

activity = <Date 2021-10-12.14:20:03.192>
actor = 'serhiy.storchaka'
assignee = 'none'
closed = True
closed_date = <Date 2021-10-12.14:20:03.194>
closer = 'serhiy.storchaka'
components = ['Library (Lib)']
creation = <Date 2015-01-18.04:16:56.445>
creator = 'ssokolow'
dependencies = []
files = ['45228', '45236', '45237']
hgrepos = []
issue_num = 23262
keywords = ['patch']
message_count = 47.0
messages = ['234218', '234248', '234256', '234284', '234285', '234289', '234290', '234291', '234292', '234293', '236529', '236727', '236737', '236826', '236838', '270554', '270555', '270556', '270563', '270565', '270566', '270567', '270569', '278340', '278341', '278346', '279381', '279384', '279390', '279392', '279399', '279400', '279403', '279407', '279491', '279492', '279529', '279541', '279544', '279545', '279735', '279766', '279767', '279989', '280130', '403574', '403731']
nosy_count = 10.0
nosy_names = ['phd', 'bazwal', 'ssokolow', 'ezio.melotti', 'python-dev', 'lilydjwg', 'berker.peksag', 'serhiy.storchaka', 'wyz23x2', 'Syaifulnizam']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue23262'
versions = ['Python 3.5', 'Python 3.6', 'Python 3.7']

[ssokolow]

As of Firefox 36 (currently in beta channel), the -remote option has been removed.

https://www.mozilla.org/en-US/firefox/36.0a2/auroranotes/
https://www.mozilla.org/en-US/firefox/36.0beta/releasenotes/

As such, attempting to open http://www.example.com/ using webbrowser.open() or webbrowser.open_new_tab() results in "File not Found" tabs pointing to these two URLs, respectively:

file:///home/ssokolow/openURL%28http://www.example.com/%29
file:///home/ssokolow/openURL%28http://www.example.com/,new-tab%29

As I happen to have the Dead Snakes PPA set up on Lubuntu 14.04 for use with tox, I was able to confirm this as an issue in Python 2.7, 3.1, 3.2, 3.3, and 3.4.

[pitrou]

What is the right way to do it then? It should also remain compatible with Firefox < 36.

[serhiy-storchaka]

Details: https://bugzilla.mozilla.org/show_bug.cgi?id=1080319

[ssokolow]

The proper solution is to prefer start (Windows), open (OSX), or xdg-open (everything else... usually but not always present) when present instead of calling the browser directly.

That way, you're using the same "delegate to the desktop's associations system and let the user's preferences control new window vs. new tab" behaviour on all OSes where it's reliably possible.

(Yes, it would guarantee that all open* functions are equivalent, but that's already the norm in a lot of cases... especially with Firefox where one of the guiding design principles is ensuring that the user retains control of their browsing experience.)

[pitrou]

That doesn't really answer the question. The webbrowser module is already able to use "xdg-open" (though not "open"), but it has a fallback on various concrete browsers (including Firefox) in case xdg-open doesn't work / doesn't exist.

[ssokolow]

Well, then the code which chooses a backend is broken because I have xdg-open and, according to WinPdb, it's using the Mozilla backend.

This was my local workaround:

    if os.name == 'posix' and not platform.mac_ver()[0]:
        with open(os.devnull, 'wb') as nul:
            subprocess.Popen(['xdg-open', request_url], stdout=nul, stderr=nul)
    else:
        webbrowser.open_new_tab(request_url)

(This retrofit branch hasn't yet reached the point where it'll be tested on Windows. I may still add another branch which calls start directly if it proves to have the same priority bug on Windows.)

[pitrou]

Well, then the code which chooses a backend is broken because I have
xdg-open and, according to WinPdb, it's using the Mozilla backend.

You have xdg-open under Windows?

[ssokolow]

WinPdb = Windowed Pdb, not MS Windows Pdb.

sudo apt-get install winpdb

[pitrou]

Oops, sorry. The best way forward would be for you to investigate and find out why xdg-open isn't preferred in your setting.

[ssokolow]

Noted. I'm not sure what my schedule will be like, but I'll try.

(I may get back to you with an answer later today or I may not within the week.)

[phdru]

I created the attached module to work with new FF in Python 2.7. You can convert it to proper patch for webbrowser.py.

[bazwal]

I arrived at an almost identical solution to the one given by Oleg. It works for me with FF 28, 35 & 36 - but presumably there are earlier versions where it does not, otherise why have the -remote option at all?

The gist of the Mozilla bug report is that the option has existed for a very long time, but there are now other command-line options that do exactly the same thing. So the only question seems to be whether Python should still support those older versions of FF that actually require it (if any exist).

On the xdg-open issue: the $BROWSER env var has priority over the default list of browsers to try, so that might explain why xdg-open is not being used on some systems (that is how I originally became aware of this problem).

[serhiy-storchaka]

--new-window and --new-tab are Firefox and SeaMonkey2.x only. [1] So this will break the support of IceApe on Debian Etch (iceape v.1.0.13 [2]).

[1] https://developer.mozilla.org/en-US/docs/Mozilla/Command_Line_Options
[2] http://archive.debian.net/etch/devel/iceape