This reverts commit fbdc9a2d03.
It was not submitted through a merge request and broke CI. Reverting it
immediately to unbreak CI and hence the rest of the development
pipeline. The changes can be re-submitted as a merge request so they’re
properly tested in CI before being merged.
See https://gitlab.gnome.org/GNOME/glib/-/merge_requests/3857#note_1994336
The previous commit enabled the `/run/mount/utab` monitoring. The problem
is that the `mount-changed` signal can be emitted twice for one mount. One
for the `/proc/mounts` file change and another one for the `/run/media/utab`
file change. This is still not ideal because e.g. the `GMount` objects for
mounts with the `x-gvfs-hide` option are added and immediately removed.
Let's enable the `mnt_monitor_veil_kernel` option to avoid this.
Related: https://github.com/util-linux/util-linux/pull/2725
The `GUnixMountMonitor` object implements monitoring on its own currently.
Only the `/proc/mounts` file changes are monitored. It is not aware of the
`/run/mount/utab` file changes. This file contains the userspace mount
options (e.g. `x-gvfs-notrash`, `x-gvfs-hide`) among others. There is a
problem when `/sbin/mount.<type>` (e.g. `mount.nfs`) helper programs are
used. In that case, the `/run/mount/utab` file is updated later than the
`/proc/mounts` file and thus the `GUnixMountMonitor` clients (e.g.
`gvfs-udisks2-volume-monitor`, `gvfsd-trash`) don't see the userspace
options until the next `mount-changed` signal. Let's use the `libmnt_monitor`
API for monitoring instead and emit the `mount-changed` signal also when the
`/run/mount/utab` file is changed.
Related: https://issues.redhat.com/browse/RHEL-14607
Related: https://github.com/util-linux/util-linux/pull/2607
This fixes a race condition which frequently caused the
`memory-monitor-dbus.py` test to fail.
The registration of the `LowMemoryMonitor` object on the bus, and the
`GMemoryMonitorDBus`’s connection to the warning signal raced, such that
it was possible for the mock `LowMemoryMonitor` to emit a warning signal
before the `GMemoryMonitorDBus` proxy was listening, and hence the proxy
would never see the signal.
Fix this by explicitly synchronising the two before proceeding to the
tests.
Make the same changes in the `memory-monitor-portal.py` test too, even
though that one was not failing. This should remove the need for a 2s
wait on every test run.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Fixes: #2887
Otherwise the test can go on to wait for a signal from the service
before it’s actually finished starting up.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #2887
Rather than sleeping and blocking everything, use a timeout source on
the main context so that inputs can continue to be handled while waiting
for a timeout.
This introduces no functional changes to the test.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #2887
It should be doing already (or the tests would never work), but make it
clearer in the code that the same `GMainContext` is being iterated as is
being woken up in the rest of the test.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #2887
When linking static libraries, multiple resources is an error unless
handled in a special way. glib and gobject do not have this problem,
as they already only include resources when building a shared lib.
I ran Bustle/dbus-monitor on the session bus while running the full GLib
test suite, and noticed that these tests were causing `Launched` signal
emissions on the main session bus. That suggested they weren’t isolated
properly, which at best causes noise on the bus and at worst could cause
spurious test failures.
Fix that by running those tests in a `GTestDBus` environment, as some of
the other appinfo tests already are.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
As seen in [CI](https://gitlab.gnome.org/GNOME/glib/-/jobs/3436216):
```
==13767== 144 (40 direct, 104 indirect) bytes in 1 blocks are definitely lost in loss record 528 of 562
==13767== at 0x4A18B2C: g_type_create_instance (gtype.c:1928)
==13767== by 0x49F92FF: g_object_new_internal (gobject.c:2235)
==13767== by 0x49FA247: g_object_new_valist (gobject.c:2574)
==13767== by 0x49F8D81: g_object_new (gobject.c:2047)
==13767== by 0x4AE2337: g_inet_socket_address_new (ginetsocketaddress.c:387)
==13767== by 0x4B1DB94: g_socket_address_new_from_native (gsocketaddress.c:230)
==13767== by 0x4B16CC2: g_socket_get_local_address (gsocket.c:2071)
==13767== by 0x40E102: test_receive_bytes_from (socket.c:2469)
==13767== by 0x4901E78: test_case_run (gtestutils.c:2974)
==13767== by 0x49022B2: g_test_run_suite_internal (gtestutils.c:3069)
==13767== by 0x490241A: g_test_run_suite_internal (gtestutils.c:3088)
==13767== by 0x4902690: g_test_run_suite (gtestutils.c:3168)
==13767== by 0x4900C8F: g_test_run (gtestutils.c:2275)
==13767== by 0x40EE8A: main (socket.c:2614)
```
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #3220
There are several reasons why we might not be able to do the test setup
for --external-data: non-Linux platform, missing ld or objcopy,
objcopy doesn't support --add-symbol, or the CPU family is MIPS
(on which cc -r does not necessarily emit the specific MIPS ABI flavour
that we are targeting, for example different functionality levels or
different NaN encodings).
If we can't link in the test data, then obviously this test is not going
to pass. It was already skipped on non-Linux, but not on platforms that
hit one of the other reasons for the test setup to fail.
In particular, this test failed on Debian mips64el since commit 81059169,
which stopped linking the necessary resource on MIPS platforms, but
continued to assert that the resource is present at runtime.
Fixes: 81059169 "GIO/tests: skip test_resources_binary on MIPS platform"
Resolves: https://gitlab.gnome.org/GNOME/glib/-/issues/3226
Signed-off-by: Simon McVittie <smcv@debian.org>
The title of an interface can be arbitrarily long, considering that
reverse DNS namespaces can be pretty complex. Instead of using the whole
interface name, we can use the name without the prefix.
Generating gir and typelib files has inter-dependencies that may depend
on other elements.
For example, glib requires gobject and gdump generated files require
gmodule, so we've a cyclic dependency because gmodule requires gobject,
that requires glib.
To prevent this, let's just generate the introspection files at once in
a different meson file so that we don't have to deal with this.
As per this we could even revert commit fa37ab6d0 since gio is now
compiled before the gir files.
The code for stripping the query and fragment from file:// URIs was
wrong, as it would not properly strip a query if there was a fragment.
Fortunately, that code was actually useless, as the "stripped URI" was
passed to g_filename_from_uri() that does proper stripping itself.
So simply drop this extra unnecessary stripping logic from GLocalVFS's
get_file_for_uri() and let g_filename_from_uri() do all the work.
The same struct was reused across multiple tests, but without a shared
way of freeing its members. Refactor to add one.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
The current buffer API is pretty much C-specific, and cannot be
adequately described in a way that is friendly to introspection and
language bindings: the passed buffer is allocated by the caller, but the
written size of the buffer is in the return value.
Using GBytes, we get a better API at the cost of an additional
allocation.
This is just the result of running `black $(git ls-files '*.py')`.
For some reason, the `sh-and-py-check` CI job didn’t run on merge
request !3751, so this non-standard formatting slipped through onto
`main`.
See https://gitlab.gnome.org/GNOME/glib/-/merge_requests/3754#note_1939914
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
It can cause failures for shared connection objects.
What can currently happen is this:
1. A user starts to asynchronously create a proxy object
2. A user starts to asynchronously create another proxy object
At this point, the asynchronous initialization for the two proxy objects
share the not yet initialized connection object.
3. While the shared connection objected is created, the user cancels the
creation with the supplied cancellable from the fist proxy object.
4. initable_init caches the canceled error and marks the connection as
initialized.
5. The initialization of the second proxy object fails with the same
canceled error.
To avoid this, clear the error in this case and destroy any member
variables that may have been created before the creation was canceled.
This way, the initialization of the second proxy object will restart the
connection initialization and with probably succeed.
Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>
See the previous commit. These additions were kept in a separate commit
to make the changes to the existing tests in the previous commit
clearer.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #3093
Previously, the code only validated the types of *required* message
headers, and did not validate optional ones.
Now, the headers are validated in one step, and a subsequent step checks
whether the required ones are present.
The existing tests have been updated to match the new error message
wording. More tests will be added to test the new behaviour in a
subsequent commit.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Fixes: #3093
Before checking the properties of `*_proxy`, assert that there were no
errors in constructing the proxy first. Otherwise the property checks
will crash on `NULL` pointer dereferences.
The test is still intermittently buggy somewhere, but at least this
commit will cause a relevant error message to be printed on failure.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Just for debugging purposes, track whether the Connection Attempt Delay
(https://datatracker.ietf.org/doc/html/rfc8305#section-8) has been
reached for each attempt.
This makes it a bit easier to diagnose `GSocketClient` problems in a
debugger.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
This makes it match the terminology from RFC 8305 better, which refers
to a ‘connection attempt delay’. This is a delay because it determines
the spacing between trying additional connection attempts. It’s not a
timeout because it shouldn’t cause cancellation of any ongoing
connection attempts.
This commit introduces no functional changes.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
`TCP_NODELAY` disables Nagle’s algorithm, which is generally a better
default for modern networks than having it enabled. Nagle’s algorithm
delays sending small data blobs until they fill an entire TCP segment,
so as to amortise the cost of sending the segment.
This improves bandwidth at the cost of latency. Given the large
bandwidth capabilities of most modern networks, most streams are
constrained by latency rather than bandwidth, so disabling Nagle’s
algorithm makes sense.
Various other major bits of software (such as libcurl) already disable
Nagle’s algorithm by default.
Specific applications which need it can turn it back on by calling
`g_socket_set_option()`.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Fixes: #791
As spotted by Michael Catanzaro in
https://gitlab.gnome.org/GNOME/glib/-/merge_requests/3394#note_1730123,
on the code path where a `ConnectionAttempt` is cancelled, it will
currently be removed from the `connection_attempts` list by the
cancellation code, and then *again* by the `if
(task_completed_or_cancelled ())` code in
`g_socket_client_connected_callback()`.
That would previously have resulted in a double-unref of the
`ConnectionAttempt`. So change `connection_attempt_remove()` to be a
no-op if the attempt isn’t found in `connection_attempts`.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
These make it a bit easier to track the ongoing tasks, as the tasks
and/or their closures are not tracked in a big list somewhere.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
These calls are where the `GSocketClient` Happy Eyeballs code relies on
other components within GLib (and glib-networking) to complete
asynchronous operations in a timely manner. `GSocketClient` doesn’t add
its own timeouts to monitor these async operations, so if the
implementations are buggy then a `GSocketClient` operation could stall
forever.
Make that a bit clearer.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
This introduces no functional changes, but makes it a little clearer
what the variable signifies, and provides a little more information when
debugging things.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
`P_()` is for pspec strings — it gave us the option to split them out to
a separate translation domain. `_()` is for normal strings.
Spotted by Sophie Herold: https://gitlab.gnome.org/GNOME/glib/-/merge_requests/3411#note_1733329
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Nicks and blurbs don't have any practical use for gio/gobject libraries.
Leaving tests untouched since this features is still used by other libraries.
Closes#2991
Previously these properties would have been documented using the strings
from the pspec, but those will be removed in the following commit. Re-add
the documentation using those strings, but as gi-docgen documentation
comments.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #2991
In an attempt to make gobject-introspection stop warning about using
deprecated gtk-doc `Type:` tags.
It doesn’t work — the gobject-introspection parser is not clever enough
to notice the tag is inside a code block.
Still, a useful port.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #3037
GDBus has always supported matching strings with arg0 matching
(`G_DBUS_SIGNAL_FLAGS_MATCH_ARG0_PATH`). In D-Bus 1.5, support was added
to the spec for also matching object paths. This got forgotten about and
was never added to GDBus, meaning that
`G_DBUS_SIGNAL_FLAGS_MATCH_ARG0_PATH` won’t match against a signal arg0
of type `o`.
Fix that, and add a unit test.
To do so, we need to add a new `g_dbus_message_get_arg0_path()` API to
complement the existing `g_dbus_message_get_arg0()` API. The approach of
letting `g_dbus_message_get_arg0()` return an object-path *or* a string
would not work, as it’s also called in the implementation of
`G_DBUS_SIGNAL_FLAGS_MATCH_ARG0_NAMESPACE`, which must only match
string-typed arg0 values and not object-path-typed ones.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Fixes: #3183
Technically we can’t rely on it being kept alive by the `message->body`
pointer, unless we can guarantee that the `GVariant` is always
serialised. That’s not necessarily the case, so keep a separate ref on
the arg0 value at all times.
This avoids a potential use-after-free.
Spotted by Thomas Haller in
https://gitlab.gnome.org/GNOME/glib/-/merge_requests/3720#note_1924707.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #3183
It was previously 4KiB, but this isn’t enough for sniffing the
content-type of some GPT disk images (they use 4KiB sectors, and the
magic bytes are in the second sector). A buffer of 8KiB would work,
but 16KiB seems harmless and more future proof.
Most of the time, the buffer size should be set by xdgmime anyway, based
on the largest sniff buffer its database needs. Currently (with
shared-mime-info master) that’s 18730 bytes, so even with a 16KiB buffer
we’re going to potentially mis-identify a few file types.
Tested manually by modifying the example GPT image from shared-mime-info
(https://gitlab.freedesktop.org/xdg/shared-mime-info/-/blob/master/tests/mime-detection/disk.gpt)
to remove the magic at offset 0x200 and add it instead at offset 0x1000,
then running:
```
cp shared-mime-info.git/tests/mime-detection/disk.gpt ./disk-without-extension
gio info -a standard::content-type ./disk-without-extension
```
It should print `application/vnd.efi.img` rather than
`application/octet-stream`.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Fixes: #3186
This fixes a stack overflow reported by a user who had both the
definition of text/javascript from shared-mime-info 2.3 and the
definition of text/javascript from shared-mime-info 2.4 installed at the
same time. In 2.3, text/javascript is a subtype of
application/ecmascript, but in 2.4 application/ecmascript is a subtype
of text/javascript. Having both at the same time resulted in circular
inheritance.
The new logic keeps a list of all parents that have already been
checked, which is more comprehensive than the old workaround that was
implemented in commit 38869ece2 ("xdgmime: Prevent infinite loops from
badly-formed MIME registrations").
https://bugs.archlinux.org/task/80279
This fixes a load of warnings about ‘multiple comment blocks documenting
<something> identifier’.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #3037
Move it to a separate page, since it doesn’t quite make sense to
incorporate into the `GDBusConnection` docs.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #3037
Move it to a separate page, as there isn’t a `GIOScheduler` struct.
Ensure that all its functions/methods/types are correctly marked as
deprecated. Fix a few broken links about I/O priority which pointed to
it.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #3037
Move it to a separate content page as there is no `GDBusIntrospection`
type to hang the rest of the documentation off.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #3037
Adding it all to the docs for the `GDBusError` enum seemed a bit much,
so I moved it to its own content page.
Signed-off-by: Philip Withnall <pwithnall@gnome.org>
Helps: #3037
The `g_content_type_guess_for_tree` function segfaults currently when
processing filenames that are not valid unicode strings. Let's use the
`g_filename_to_utf8` and `g_utf8_make_valid` functions before other
processing to prevent that.
Let's also add a test for it to avoid this in future.
Fixes: https://gitlab.gnome.org/GNOME/glib/-/issues/3168
g_option_context_parse()/g_application_run()/g_test_init() for
convenience also call g_set_prgname(), when the prgname is unset at this
point. This was racy.
Fix the race by using an atomic compare-and-exchange and only reset the
value, if it is unset still.
When `--attributes` is specified and doesn’t include `standard::name` in
its list, `gio` would print a critical warning from the (mandatory) call
to `g_file_info_get_name()`.
Fix that by making the call to `g_file_info_get_name()` optional.
Add a unit test too.
Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>
Fixes: #3158
It gives nowhere near full coverage, but it’s something we can build on
in future.
Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>
Helps: #3158
Helps: #2950
Modify all the similar Python test wrappers to set
`G_DEBUG=fatal-warnings` in the environment of the program being tested,
so we can catch unexpected warnings/criticals.
Adding this because I noticed it was missing, not because I noticed a
warning/critical was being ignored.
Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>
If the help output is explicitly requested by the user, it’s
conventional for it to be printed to stdout rather than stderr.
Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>
Store their details in an array which can be iterated over instead.
This introduces no functional changes, just a cleanup which will allow
following commits to be neater.
Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>
If she socket is dispatched at exactly the previously set ready time,
it should already be considered to have timed out. This can easily
happen in practice when using a low resolution timer.
This fixes a test failure on GNU/Hurd, see
https://gitlab.gnome.org/GNOME/glib/-/issues/3148
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
The test only needs a unidirectional channel, and a pipe is sufficient
for that.
This may simplify things when running the test on Hurd; see
https://gitlab.gnome.org/GNOME/glib/-/issues/3148#note_1874198.
Additionally, set `O_NONBLOCK` on the pipe since the test seems to
expect that partial writes will succeed and that writes to a full buffer
will fail rather than block.
Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>
Helps: #3148
Various parts of the build (such as `objectmanager-rst-gen`) depend on
running `gdbus-codegen` after it’s been built, but they currently only
encode a dependency to the main codegen Python file and not the
supporting files. This can cause `gdbus-codegen` to fail with an
`ImportError` if the build races so that `objectmanager-rst-gen` is
built before the codegen supporting files.
Example failure here: https://gitlab.gnome.org/pwithnall/glib/-/jobs/3266471
```
FAILED: gio/tests/gdbus-object-manager-example/objectmanager-rst-gen-org.gtk.GDBus.Example.ObjectManager.Animal.rst gio/tests/gdbus-object-manager-example/objectmanager-rst-gen-org.gtk.GDBus.Example.ObjectManager.Cat.rst
/usr/bin/python3 gio/gdbus-2.0/codegen/gdbus-codegen --interface-prefix org.gtk.GDBus.Example.ObjectManager. --generate-rst objectmanager-rst-gen --output-directory gio/tests/gdbus-object-manager-example ../gio/tests/gdbus-object-manager-example/gdbus-example-objectmanager.xml
Traceback (most recent call last):
File "/builds/pwithnall/glib/_build/gio/gdbus-2.0/codegen/gdbus-codegen", line 53, in <module>
from codegen import codegen_main
File "/builds/pwithnall/glib/_build/gio/gdbus-2.0/codegen/codegen_main.py", line 29, in <module>
from . import dbustypes
File "/builds/pwithnall/glib/_build/gio/gdbus-2.0/codegen/dbustypes.py", line 22, in <module>
from . import utils
ImportError: cannot import name 'utils' from 'codegen' (/builds/pwithnall/glib/_build/gio/gdbus-2.0/codegen/__init__.py)
```
Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>
All the calls to `usage()` are immediately followed by a `return` from
`main()` which sets an appropriate exit status.
Calling `exit()` early means that running `gio --help` returns exit
status 1, which is incorrect — it should (by convention) return 0.
Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>
Depending on the operating system, /bin/sh might either be bash (for
example on Fedora or Arch) or dash (for example on Debian or Ubuntu)
or some other POSIX shell.
When bash is asked to run a simple command with no shell keywords or
metacharacters, like this one, it replaces itself with the program
via execve(), but dash does not have that optimization and treats it
like any other program invocation in a larger script: it will fork,
exec the program in the child, and wait for the child in the parent.
This seems like it conflicts with sleep_and_kill() assuming that it can
use the subprocess's process ID as the sleep(1) process ID. Specifically,
if it sends SIGKILL, it will go to the sh(1) process and not the sleep(1)
child, which could result in the sh(1) process being terminated and
its sleep(1) child being leaked.
To get the bash-like behaviour portably, explicitly use the exec builtin
to instruct the shell to replace itself with sleep(1), so that the
process ID previously used for the shell becomes the process ID of the
sleep process.
This appears to resolve an intermittent hang and test timeout on Debian
machines (especially slower ones), although I'm not 100% clear on the
mechanics of how it happens.
Resolves: https://gitlab.gnome.org/GNOME/glib/-/issues/3157
Signed-off-by: Simon McVittie <smcv@collabora.com>
`test-generated.txt` is listed in `test.gresource.xml`, so it needs to
be specified as a dependency in the `custom_target()` which uses
`test.gresource.xml`.
Fixes intermittent build failures like:
```
FAILED: gio/tests/test.gresource
/builds/GNOME/glib/_build/gio/glib-compile-resources --compiler=gcc --target=gio/tests/test.gresource --sourcedir=/builds/GNOME/glib/gio/tests --sourcedir=/builds/GNOME/glib/_build/gio/tests --internal ../gio/tests/test.gresource.xml
../gio/tests/test.gresource.xml: Failed to locate test-generated.txt in any source directory.
```
See !3671 and #3163.
Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>
This reverts commit 0b9900e4e7.
The dependency was added in the wrong place: `test-generated.txt` is
needed when compiling `test.gresource`, not when compiling the test
which ultimately uses that gresource.
See !3671 and #3163.
The PTRACE_O_EXITKILL symbol in sys/ptrace.h is an enum member, not
a macro. The #ifdef check added to the GSubprocess test-case in
272ec5dbca will not detect it.
Use cc.has_header_symbol() to properly detect it. According to the
documentation: "Symbols here include function, variable, #define,
type definition, etc.".
Fixes: 272ec5dbca
Closes: https://gitlab.gnome.org/GNOME/glib/-/issues/3156
On CHERI-enabled systems we use uintptr_t as the underlying storage for
GType and therefore casting to gsize strips the upper bits from a pointer.
Fix this by casting via uintptr_t instead and introduce a new set of
macros to convert between GType and pointers.
It needs to be in a separate page because there isn’t actually a
`GFileAttribute` type.
Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>
Helps: #3037
Move it to the struct docs, although again this is a little suspect
because there is actually no `GDBusAddress` struct/type.
Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>
Helps: #3037
This might not work, as `GContentType` isn’t actually a defined type
(content types are just strings). It would be a bit weird to create a
separate page for content types, though, as the functions handling them
are very method-like and feel like they should be grouped together like
methods of a class.
Signed-off-by: Philip Withnall <philip@tecnocode.co.uk>
Helps: #3037
Currently, the introspection data for GLib and its sub-libraries is
generated by gobject-introspection, to avoid the cyclic dependency
between the two projects.
Since gobject-introspection is generally available on installed systems,
we can check for its presence, and generate the introspection data
directly from GLib.
This does introduce a cyclic dependency, which is why it's possible to
build GLib without introspection, then build gobject-introspection, and
finally rebuild GLib.
By having introspection data available during the GLib build, we can do
things like generating documentation; validating newly added API; and
close the loop between adding new API and it becoming available to non-C
consumers of the C ABI (i.e. language bindings).
