I emerged gnome on the description from the official site. It throw an error in the gnome-extra/gconf-editor-2.30.0 Reproducible: Always Steps to Reproduce: 1.emerge app-text/gnome-doc-utils. 2.emerge gnome (or emerge gnome-extra/gconf-editor). 3. Actual Results: Emerging gnome continued.
Created attachment 257677 [details] /var/tmp/portage/gnome-extra/gconf-editor-2.30.0/temp/build.log
That's app-text/gnome-doc-utils, so likely (can't be sure, as your 'emerge --info' is missing) it's a matter of python-updater.
Please run python-updater as requested in comment #2, post your `emerge --info' output in a comment, and then reopen this bug report.