Am 12.11.20 um 09:35 schrieb tomas@tuxteam.de:
On Wed, Nov 11, 2020 at 11:57:08PM +0100, mmDebMail2020@marwedels.de wrote:
I don't know (not sure I'd want to) where Gtk keeps its MIME types database these days. But, as a shot in the dark: have you checked that your /etc/mime.types is sane? What does 'grep png /etc/mime.types' say? The file comes with Debian package mime-support, in case you need a new one.
I fixed the error.After figuring out, that glib2.0 had no data to compare the png data to in cache_get_mime_type_for_data, I stepped through xdg_mime_init_from_directory and discovered only a few data for mimetypes were added from my ~/.local/share directory. Stepping through the same code on a different computer, most data came from /usr/share/mime/mime.cache, but the file was missing on my computer. Running update-mime-database /usr/share/mime/ as root solved the problem. Took me ~7 hours to figure this out ;) Maybe this was the result of an upgrade. Because this was when the error occurred the first time.