I wanted to use jinja2 templating here too, but it's hard to get right:
custom_target() strips the executable bit by default (unlike configure_file
apparently). custom_target() has install_mode setting, but it was only added
in meson-0.47, so it can't be used while we support 0.46. And without the
executable bit the test is not invoked properly. For example, "root-unittests"
in the debian package calls test-* after installation, so the executable bit
there is necessary. It would be possible to adjust the file mode after the
fact, but it would make things more complicated.
So let's use the native meson substitutions here. We don't need anything more
fancy.
I want to stop using 'substs'. But in this case, configure_file() is nicer
than custom_target(), because it causes meson to immediately generate the
helpers after configuration, so it's possible to do
'meson build && build/man/man ...', without building anything first.
We only substitute one variable here, so let's use a custom configuration_data()
object.
m4 was hugely popular in the past, because autotools, automake, flex, bison and
many other things used it. But nowadays it much less popular, and might not even
be installed in the buildroot. (m4 is small, so it doesn't make a big difference.)
(FWIW, Fedora dropped make from the buildroot now,
https://fedoraproject.org/wiki/Changes/Remove_make_from_BuildRoot. I think it's
reasonable to assume that m4 will be dropped at some point too.)
The main reason to drop m4 is that the syntax is not very nice, and we should
minimize the number of different syntaxes that we use. We still have two
(configure_file() with @FOO@ and jinja2 templates with {{foo}} and the
pythonesque conditional expressions), but at least we don't need m4 (with
m4_dnl and `quotes').
Jinja2 inserts an empty line after the first macro body, which I don't know how
to get rid of. Only the first macro causes problems: the other ones don't have
conditional statements at the end and the issue does not occur. As a work-around
I moved ProtectHostname to the end of the first macro.
Output is identical, except for horizontal whitespace and change in position of
ProtectHostname.
HAVE_SMACK_RUN_LABEL was dropped back in 348b44372f,
so one line in etc.conf was not rendered as expected ;(
Checking if names are defined is paying for itself!
The comment talks about upstream development steps and doesn't make
sense for users. We used special '## ' syntax to strip it out during
build, but it got inadvertently reformatted as a normal comment
in 3982becc92.
We don't need two (and half) templating systems anymore, yay!
I'm keeping the changes minimal, to make the diff manageable. Some enhancements
due to a better templating system might be possible in the future.
For handling of '## ' — see the next commit.
m4 was nice in '85, but the syntax feels a bit dated. Since we use python for
meson, let's use a popular python templating engine to replace some m4 usage.
A little nicety is that typos are caught:
FAILED: sysusers.d/systemd-remote.conf
/usr/bin/meson --internal exe --capture sysusers.d/systemd-remote.conf -- /home/zbyszek/src/systemd/tools/meson-render-jinja2.py config.h ../sysusers.d/systemd-remote.conf.j2
Traceback (most recent call last):
File "/home/zbyszek/src/systemd/tools/meson-render-jinja2.py", line 28, in <module>
print(render(sys.argv[2], defines))
File "/home/zbyszek/src/systemd/tools/meson-render-jinja2.py", line 24, in render
return template.render(defines)
File "/usr/lib/python3.9/site-packages/jinja2/environment.py", line 1090, in render
self.environment.handle_exception()
File "/usr/lib/python3.9/site-packages/jinja2/environment.py", line 832, in handle_exception
reraise(*rewrite_traceback_stack(source=source))
File "/usr/lib/python3.9/site-packages/jinja2/_compat.py", line 28, in reraise
raise value.with_traceback(tb)
File "<template>", line 8, in top-level template code
jinja2.exceptions.UndefinedError: 'HAVE_MICROHTTP' is undefined
This checking mirrors what 349cc4a507 did for C defines.
User managers always pass their environment on to their children.
Make that clear in the description of ManagerEnvironment= which
states that none of those args will get passed to child processes of
service managers.
In the change set 6c045a9998 the error
text for the old flag `--private-users-chown` was repurposed for the
new flag `--private-users-ownership=own` and while doing so the word
`may` was dropped leading to a grammatically incorrect error text.
