Intermittent network unreachable error from GSocket connecting with non-functioning IPv6 network
Testing Geary master against Flatpak org.gnome.Sdk/x86_64/master over the last few days there's a good chance each time of geting an G_IO_ERROR_NETWORK_UNREACHABLE error from GSocket when connecting to a remote host that has both A and AAAA records, from a local host that has a functioning IPv4 interface and a configured-but-non-functional IPv6 interface. I.e. the local host is on a working IPv4 network, has "Automatic" selected under the IPv6 tab for the network (and hence has a fe80:: link-local address), but otherwise is not connected to an IPv6 network.
Since this happens often-but-intermittently for host names with both A and AAAA records (and not at all for hosts with only A records), I assume the error occurs when attempting and failing to connect to the AAAA address first, and doesn't when connecting first to the A record. Further, disabling IPv6 in the control panel seems to make it impossible to reproduce the error. Could be related to #1555 (closed), I guess?