[🐛 Bug]: Defaulting the Firefox binary to `firefox-bin` fails to start Firefox 121 and later

[whimboo]

What happened?

With the Firefox 121 release several Selenium bindings are not able to start Firefox via geckodriver because the default Firefox binary as found by Selenium will be used by specifying the firefox-bin binary instead of just firefox. We got this report earlier today via @soulgalore on mozilla/geckodriver#2144.

As it looks like several bindings use firefox-bin and need to be corrected to use firefox instead:
https://github.com/search?q=repo%3ASeleniumHQ%2Fselenium+firefox-bin&type=code

How can we reproduce the issue?

Install Firefox 121 and run a Selenium script that auto-detects the default installation of Firefox on the MacOS system.

Relevant log output

There is no output but the process gets immediately killed because of https://bugzilla.mozilla.org/show_bug.cgi?id=1871447.

Operating System

MacOS (all versions)

Selenium version

Most recent

What are the browser(s) and version(s) where you see this issue?

Firefox 121 and later

What are the browser driver(s) and version(s) where you see this issue?

geckodriver 0.33.0

Are you using Selenium Grid?

No

[github-actions]

@whimboo, thank you for creating this issue. We will troubleshoot it as soon as we can.

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Thank you!

[whimboo]

Note that on MacOS you should read the actual binary from the Info.plist file. Any hard-coded path should be avoided.

[whimboo]

CC maintainers of Selenium to make them aware of the current breakage with Firefox 121.

@titusfortner @AutomatedTester @shs96c @jimevans @diemol

[titusfortner]

Well, Selenium Manager does the right thing, so that's a good first step.

It looks like we support a user passing in the full path to the binary, which we can't fix, but some languages also support passing in the directory and adding the binary to it. How long has firefox been a valid alternative to firefox_bin?

[titusfortner]

you should read the actual binary from the Info.plist file

I don't think Selenium should be reading from anything. I'm not even sure the code should be looking inside a provided directory.

Maybe this is a good excuse to deprecate the various FirefoxBinary classes. We needed them in Selenium 2, we do not need them in Selenium 4.

[whimboo]

Maybe but I cannot talk about other drivers beside geckodriver. At least on our side you can specify an app bundle and we will resolve the binary automatically.

Which versions of Selenium are directly affected by this problem? I'm asking because you say that those classes are not needed for Selenium 4.

[whimboo]

It looks like we support a user passing in the full path to the binary, which we can't fix, but some languages also support passing in the directory and adding the binary to it. How long has firefox been a valid alternative to firefox_bin?

Both binaries basically exist forever and firefox-bin is actually a duplicate that we may wanna remove. So using firefox will be the right thing to do.

[diemol]

I had a look at the code base, and we have a few places where firefox-bin is used.

• In JavaScript, the Channel class inside Firefox, aims to help the user with some predefined locations for Nightly, etc.
• In Java, the FirefoxBinary class tries to do the same thing and uses firefox-bin only when the system property webdriver.firefox.bin is used.
• In Python, also a FirefoxBinary class, with the same intention as Java and JavaScript.

However, those are all helper classes, and they are not needed for recent versions of Selenium, more specifically because they were used when GeckoDriver was not around and Selenium was doing the heavy lifting.

Users can always:

• Use Selenium Manager by not having any GeckoDriver on PATH
• Avoid using those helper classes and, if needed pass the browser binary path through the browser options

What we can do in Selenium, is to update those mentions of firefox-bin and leave firefox, and then deprecate those helper classes because they are not needed.

[titusfortner]

@diemol I know you deprecated these helpers, should we also change firefox-bin until we remove them?

[diemol]

I changed the firefox-bin string to firefox already. Did I miss something?

[titusfortner]

There were still 2 references still the last time I searched. Not at the code right now.

[titusfortner]

So, I think this is done. The helpers will be removed after 2 releases per our policy.