The macro used to return NULL if input was NULL or had the wrong type. Now
it asserts that input is nonnull and it has the expected type.
There are a few places where a missing or mismatched type was OK, but in a
majority of places, we would do both of the asserts. In various places we'd
only do one, but that was by ommission/mistake. So moving the asserts into the
macro allows us to save some lines.
This commit is the first in the series, and they generally follow the same
idea: we had very detailed logging for message append operations which would
only fail either with some type error or intrinsic limit (and then they would
fail everywhere, so this would be noticed during development or in CI), or they
would fail with ENOMEM, in which case the exact location is not very interesting
since this is not repeatable.
I am in general in favour of detailed logging messages, because it helps with
diagnosis of errors, but I think case is an exception. Despite not being very
useful, those messages required a lot of effort, because they were customized
for each and every append operation. In fact some of the messages contained copy
errors. The text of the messages (since they are generally unique) also added up
to a considerable size.
This removes the log messages after each sd_netlink_message_append_*() in
fill_message_create() with a single line in netdev_create(). As described
above, we are just appending fields to a message, so those calls would almost
never fail.
A forgotten 'return' was added in one place.
$ size build/systemd-networkd{.0,}
text data bss dec hex filename
1878634 394016 36 2272686 22adae build/systemd-networkd.0
1842450 394080 36 2236566 222096 build/systemd-networkd
… so we save 30k too.