1477513 - Attempt to open MHT file opens tabs forever, requires power button restart!

Status: RESOLVED DUPLICATE of bug 218257

(Firefox :: File Handling, defect)

Description

[LorenAmelang]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:61.0) Gecko/20100101 Firefox/61.0
Build ID: 20180704003137

Steps to reproduce:

Ok, this is an odd use case...  But the result is rather disastrous, so I think it deserves attention. I'm visually handicapped, and my best way to read anything is the Tranquility add-on in Firefox. Many incoming eMails include an "open in browser" link, which works great. But some don't. They are stored in .eml format, which can be renamed to .mht and opened in a browser (they work great in IE). So I thought I'd just open them in Firefox. 


Actual results:

Whether a .mht file is opened via the address bar or via Win 10 "Open with", Firefox instantly begins opening tabs, hundreds of them, faster than I can even see if anything gets drawn in any of them. Of course each new tab grabs the focus from any other apps or controls...  You can click the top right Close 'X' and give it permission to close the hundreds of open tabs, but by the time you've done that, there are more tabs opened behind that dialog and Firefox can't close. The only solution I found was to hold the power button for a forced restart. 


Expected results:

Obviously I'd like the .mht files to just open, but from what I see on the web, Firefox Quantum isn't going to support that. So maybe you could at least put up an error dialog saying you can't open .mht files? Or do nothing? Locking up the host computer and requiring a brute-force kill-and-restart is not good form!

Comment 1

[Gingerbread Man]

Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:61.0) Gecko/20100101 Firefox/61.0
20180704003137

Attempting to open an EML renamed to MHT — either directly from the address bar or from File → Open — results in a "What should Firefox do with this file?" dialog. You must've selected "Open with: Firefox" there, which is what led to the infinite loop.

When Firefox is associated with the file type in Windows, that's bug 215554.

1. In Windows, associate EML and MHT files with applications that can actually handle them, like the Mail app and Internet Explorer, respectively.
2. In Firefox, click the menu button, then Options. In the Applications section, make sure EML and MHT files are set to open with their default handlers. You can also reset the section to starting defaults by deleting handlers.json from your profile folder [1] while Firefox is closed.


[1] https://support.mozilla.com/kb/profiles-where-firefox-stores-user-data

Comment 2

[LorenAmelang]

@Gingerbread Man,

Thank you for the details about how to clean up after my chaotic attempt. But how are users supposed to know not to do this? We see a file open properly in IE, and figure maybe Firefox is at least as competent...  If Firefox asks us what we want done with the file, of course we'll say "open it". 

So it has been known for fifteen years that this creates an infinite loop? And nobody in all that time has considered it worth preventing an infinite loop? I'm speechless.

Comment 3

[Gingerbread Man]

That's been my complaint as well in bug 218257, comment 62.