Description of problem: After installing Firefox Nightly, I wanted to set it as the default in Gnome Settings. However, it crashes when I try to select "Nightly" as the default application. Version-Release number of selected component: control-center-3.14.2-2.fc21 Additional info: reporter: libreport-2.3.0 backtrace_rating: 4 cmdline: gnome-control-center --overview crash_function: default_app_changed executable: /usr/bin/gnome-control-center kernel: 3.18.6-200.fc21.x86_64 runlevel: N 5 type: CCpp uid: 1000 Truncated backtrace: Thread no. 1 (10 frames) #0 default_app_changed at cc-info-panel.c:893 #5 gtk_combo_box_set_active_internal at gtkcombobox.c:4405 #6 gtk_combo_box_set_active_iter at gtkcombobox.c:4463 #7 gtk_combo_box_menu_activate at gtkcombobox.c:3298 #8 g_cclosure_marshal_VOID__STRINGv at gmarshal.c:1004 #9 _g_closure_invoke_va at gclosure.c:831 #12 item_activated_cb at gtktreemenu.c:1481 #17 gtk_widget_activate at gtkwidget.c:7806 #18 gtk_menu_shell_activate_item at gtkmenushell.c:1380 #19 gtk_menu_shell_button_release at gtkmenushell.c:792 Potential duplicate: bug 958288
Created attachment 992908 [details] File: backtrace
Created attachment 992909 [details] File: cgroup
Created attachment 992910 [details] File: core_backtrace
Created attachment 992911 [details] File: dso_list
Created attachment 992912 [details] File: environ
Created attachment 992913 [details] File: exploitable
Created attachment 992914 [details] File: limits
Created attachment 992915 [details] File: maps
Created attachment 992916 [details] File: open_fds
Created attachment 992917 [details] File: proc_pid_status
Created attachment 992918 [details] File: var_log_messages
Where did you install it from? How did you install it? Your .desktop file for the application seems to export a mime-type that says it handles HTTP (otherwise it wouldn't show up in the list) but then doesn't list any mime-types (which returns NULL, hence the crash).
The Firefox Nightly build is Mozilla's official x86_64 binary, unzipped and run locally from my local directory. It prompts to set itself as the default browser, which seems not to work properly. This might be a bug in Firefox too, but it shouldn't crash gnome-control-center.
$ gvfs-mime --query x-scheme-handler/http Default application for 'x-scheme-handler/http': userapp-Nightly-J4KDUX.desktop Registered applications: userapp-Nightly-J4KDUX.desktop google-chrome.desktop firefox.desktop epiphany.desktop Recommended applications: userapp-Nightly-J4KDUX.desktop google-chrome.desktop firefox.desktop epiphany.desktop $ cat /home/hadess/.local/share/applications/userapp-Nightly-J4KDUX.desktop [Desktop Entry] Encoding=UTF-8 Version=1.0 Type=Application NoDisplay=true Exec=/home/hadess/Downloads/firefox/firefox %u Name=Nightly Comment=Custom definition for Nightly commit d9f08df39cafbd1f15c510da444f8ac913cdc493 Author: Bastien Nocera <hadess> Date: Wed Feb 18 10:10:08 2015 +0100 info: Fix crash when application supports no mime-type It seems to be possible for Firefox Nightly to set itself up as the default x-scheme-handler/http without actually handling any mime-types. See https://bugzilla.redhat.com/show_bug.cgi?id=1193680 https://bugzilla.gnome.org/show_bug.cgi?id=744695 You'll want to file a bug against Firefox so it adds the MimeTypes= line when creating its own .desktop file though.
Thanks for a quick response! Firefox bug filed here: https://bugzilla.mozilla.org/show_bug.cgi?id=1134720