[SOLVED] Firefox closes when trying to open a download

Environment:
Slackware 14.2 Stable, up to date. Firefox 68.12.0esr (64-bit)

In Firefox when I download a file and choose the option “open with” but choose a program which is not the default, Firefox will close. When I reopen Firefox and try again, the default program is now listed as what I tried (changed to) the first time, and then it does work.

Example. Try to download this file
https://sample-videos.com/csv/Sample...et-10-rows.csv
If “open with” recommends a spreadsheet program then try to open with Kate, for example.

Saving to disk always works and is of course a work-around. But what I'm doing should not crash the browser.

Have you tried this while running firefox from the CLI? It might provide some output that can help determine the issue.

Originally Posted by MrHull Environment: Slackware 14.2 Stable, up to date. Firefox 68.12.0esr (64-bit) In Firefox when I download a file and choose the option “open with” but choose a program which is not the default, Firefox will close. When I reopen Firefox and try again, the default program is now listed as what I tried (changed to) the first time, and then it does work. Example. Try to download this file https://sample-videos.com/csv/Sample...et-10-rows.csv If “open with” recommends a spreadsheet program then try to open with Kate, for example. Saving to disk always works and is of course a work-around. But what I'm doing should not crash the browser.

Same Slackware version, exact same Firefox version and opening the link worked here, it launched Kwrite, document loaded with the file content

[edit]
Changed the app and tried to open it with Kate and Firefox indeed did quit

Running Firefox from terminal, got these messages

Exiting due to channel error.
Exiting due to channel error.
Exiting due to channel error.
Segmentation fault

[edit2]
Quick search leads to an old bug
https://bugzilla.mozilla.org/show_bug.cgi?id=1244305

Simple workaround rather than modifying firefox source code and recompile it would be:
- Go to firefox preferences (about:preferences)
- Then change prefered application for document CSV in Files and Application > Application
(using csv in search bar)

Thanks for your sleuthing. Looks like you found the exact bug, which is still there after 5 years. And yes, I get those same messages in the terminal.
There's no quick fix but I will mark this as solved since I see it's not a Slackware bug.

Should this be marked as "solved" since we know what it is now?

I would say yes, because there's nothing else that can be done about it here, but that's just me.