Comment # 1 on bug 1141201 from Martin Li��ka

Can be reproduced with:

$ gdb /usr/lib/tracker-miner-fs
...
(tracker-miner-fs:3082): GLib-GObject-WARNING **: 08:51:14.685: cannot register
existing type 'TrackerSparqlConnection'

(tracker-miner-fs:3082): GLib-CRITICAL **: 08:51:14.685: g_once_init_leave:
assertion 'result != 0' failed

(tracker-miner-fs:3082): GLib-GObject-CRITICAL **: 08:51:14.685:
g_type_register_static: assertion 'parent_type > 0' failed

(tracker-miner-fs:3082): GLib-GObject-WARNING **: 08:51:14.685: cannot add
private field to invalid (non-instantiatable) type '<invalid>'

(tracker-miner-fs:3082): GLib-CRITICAL **: 08:51:14.685: g_once_init_leave:
assertion 'result != 0' failed

(tracker-miner-fs:3082): GLib-GObject-CRITICAL **: 08:51:14.685:
g_object_new_with_properties: assertion 'G_TYPE_IS_OBJECT (object_type)' failed

(tracker-miner-fs:3082): Tracker-CRITICAL **: 08:51:14.685:
tracker_sparql_backend_load_plugins: assertion 'self != NULL' failed

Thread 1 "tracker-miner-f" received signal SIGSEGV, Segmentation fault.
0x00007ffff7d8a5ce in ?? () from /usr/lib64/libtracker-sparql-2.0.so.0
(gdb) bt
#0  0x00007ffff7d8a5ce in ?? () from /usr/lib64/libtracker-sparql-2.0.so.0
#1  0x00007ffff7d8ac78 in tracker_sparql_connection_get () from
/usr/lib64/libtracker-sparql-2.0.so.0
#2  0x00007ffff7db89ed in ?? () from /usr/lib64/libtracker-miner-2.0.so.0
#3  0x00007ffff7db984e in ?? () from /usr/lib64/libtracker-miner-2.0.so.0
#4  0x000055555556a335 in ?? ()
#5  0x00007ffff7cabbc2 in g_initable_new_valist () from
/usr/lib64/libgio-2.0.so.0
#6  0x00007ffff7cabc79 in g_initable_new () from /usr/lib64/libgio-2.0.so.0
#7  0x0000555555567389 in tracker_miner_files_new ()
#8  0x000055555555f179 in main ()

So for some reason we can't load TrackerSparqlConnection. On a working system
there is no WARNING/CRITICAL message.

I've noticed following warning even without LTO:

 g-ir-scanner: link: cc -o
/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/tmp-introspectuu1v_sse/TrackerMiner-2.0
-O2 -Wall -D_FORTIFY_SOURCE=2 -fstack-protector-strong -funwind-tables
-fasynchronous-unwind-tables -fstack-clash-protection -g
/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/tmp-introspectuu1v_sse/TrackerMiner-2.0.o
-L. -Wl,-rpath,. -Wl,--no-as-needed
-L/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-miner
-Wl,-rpath,/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-miner
-L/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-miner
-Wl,-rpath,/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-miner
-L/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-common
-Wl,-rpath,/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-common
-L/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-sparql-backend
-Wl,-rpath,/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-sparql-backend
-L/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-sparql
-Wl,-rpath,/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-sparql
-L/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-remote
-Wl,-rpath,/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-remote
-L/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-bus
-Wl,-rpath,/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-bus
-L/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-direct
-Wl,-rpath,/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-direct
-L/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-data
-Wl,-rpath,/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/libtracker-data
-L/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/gvdb
-Wl,-rpath,/home/abuild/rpmbuild/BUILD/tracker-2.2.2/build/src/gvdb
-ltracker-miner-2.0 -lglib-2.0 -lgio-2.0 -lgobject-2.0 -lm -luuid -lnm
-lgio-2.0 -lgobject-2.0 -Wl,--export-dynamic -pthread -lgmodule-2.0 -lglib-2.0
 ../src/libtracker-miner/tracker-miner-object.c:611: Warning: TrackerMiner:
tracker_miner_get_connection: return value: Unresolved type:
'TrackerSparqlConnection*'

Maybe it's related. Anyway, I create an upstream issue for it:
https://gitlab.gnome.org/GNOME/tracker/issues/117