Meson has a common pattern of using 'if len(foo) == 0:' or
'if len(foo) != 0:', however, this is a common anti-pattern in python.
Instead tests for emptiness/non-emptiness should be done with a simple
'if foo:' or 'if not foo:'
Consider the following:
>>> import timeit
>>> timeit.timeit('if len([]) == 0: pass')
0.10730923599840025
>>> timeit.timeit('if not []: pass')
0.030033907998586074
>>> timeit.timeit('if len(['a', 'b', 'c', 'd']) == 0: pass')
0.1154778649979562
>>> timeit.timeit("if not ['a', 'b', 'c', 'd']: pass")
0.08259823200205574
>>> timeit.timeit('if len("") == 0: pass')
0.089759664999292
>>> timeit.timeit('if not "": pass')
0.02340641999762738
>>> timeit.timeit('if len("foo") == 0: pass')
0.08848102600313723
>>> timeit.timeit('if not "foo": pass')
0.04032287199879647
And for the one additional case of 'if len(foo.strip()) == 0', which can
be replaced with 'if not foo.isspace()'
>>> timeit.timeit('if len(" ".strip()) == 0: pass')
0.15294511600222904
>>> timeit.timeit('if " ".isspace(): pass')
0.09413968399894657
>>> timeit.timeit('if len(" abc".strip()) == 0: pass')
0.2023209120015963
>>> timeit.timeit('if " abc".isspace(): pass')
0.09571301700270851
In other words, it's always a win to not use len(), when you don't
actually want to check the length.
Ideally, all dependency objects should support this, but it's a lot of
work and isn't supported by all dependency types (like frameworks and
pkg-config), so for now just enable it for external libraries.
This would make it harder to parse an option to mesonconf such
as -Dfoo:bar:baz:fun=value since it could mean either of these:
* For subproject 'foo:bar:baz', set the option 'fun' to 'value'
* For subproject 'foo:bar', an invalid option 'baz:fun' was set
To differentiate between these two we'd need to create the list of
subprojects first and then parse their options later, which
complicates the parsing quite a bit.
You can now pass a list of strings to the install_dir: kwarg to
build_target and custom_target.
Custom Targets:
===============
Allows you to specify the installation directory for each
corresponding output. For example:
custom_target('different-install-dirs',
output : ['first.file', 'second.file'],
...
install : true,
install_dir : ['somedir', 'otherdir])
This would install first.file to somedir and second.file to otherdir.
If only one install_dir is provided, all outputs are installed there
(same behaviour as before).
To only install some outputs, pass `false` for the outputs that you
don't want installed. For example:
custom_target('only-install-second',
output : ['first.file', 'second.file'],
...
install : true,
install_dir : [false, 'otherdir])
This would install second.file to otherdir and not install first.file.
Build Targets:
==============
With build_target() (which includes executable(), library(), etc),
usually there is only one primary output. However some types of
targets have multiple outputs.
For example, while generating Vala libraries, valac also generates
a header and a .vapi file both of which often need to be installed.
This allows you to specify installation directories for those too.
# This will only install the library (same as before)
shared_library('somevalalib', 'somesource.vala',
...
install : true)
# This will install the library, the header, and the vapi into the
# respective directories
shared_library('somevalalib', 'somesource.vala',
...
install : true,
install_dir : ['libdir', 'incdir', 'vapidir'])
# This will install the library into the default libdir and
# everything else into the specified directories
shared_library('somevalalib', 'somesource.vala',
...
install : true,
install_dir : [true, 'incdir', 'vapidir'])
# This will NOT install the library, and will install everything
# else into the specified directories
shared_library('somevalalib', 'somesource.vala',
...
install : true,
install_dir : [false, 'incdir', 'vapidir'])
true/false can also be used for secondary outputs in the same way.
Valac can also generate a GIR file for libraries when the `vala_gir:`
keyword argument is passed to library(). In that case, `install_dir:`
must be given a list with four elements, one for each output.
Includes tests for all these.
Closes https://github.com/mesonbuild/meson/issues/705
Closes https://github.com/mesonbuild/meson/issues/891
Closes https://github.com/mesonbuild/meson/issues/892
Closes https://github.com/mesonbuild/meson/issues/1178
Closes https://github.com/mesonbuild/meson/issues/1193
The configure_file command raised an exception when an input was specified as a
File, because os.path.join does not take File objects directly. This patch
converts a File object to a string and adjusts the subsequent os.path.join
calls.
Points to the `mesonintrospect.py` script corresponding to the
currently-running version of Meson.
Includes a test for all three methods of running scripts/commands.
Closes https://github.com/mesonbuild/meson/issues/1385
Now as long as you have a C compiler available in the project, it will
be used to compile assembly even if the target contains a C++ compiler
and even if the target contains only assembly and C++ sources.
Earlier, the order in which sources appeared in a target would decide
which compiler would be used.
However, if the project only provides a C++ compiler, that will be
used for compiling assembly sources.
If this breaks your use-case, please tell us.
Includes a test that ensures that all of the above is adhered to.
Use an ordered dict for the compiler dictionary and sort it according
to a priority order: fortran, c, c++, etc.
This also ensures that builds are reproducible because it would be
a toss-up whether a C or a C++ compiler would be used based on the
order in which compilers.items() would return items.
Closes https://github.com/mesonbuild/meson/issues/1370
An empty / no-op dependency can be expressed as []. This works with
the dependencies kwarg in executable targets such as shared_library,
but now with declare_dependency, where it would error out with
"error: Dependencies must be external deps" because the deps are
not flattened in this case. This patch fixes that.
Fixes#1500
Special wrap modes:
nofallback: Don't download wraps for dependency() fallbacks
nodownload: Don't download wraps for all subproject() calls
Subprojects are used for two purposes:
1. To download and build dependencies by using .wrap files if they
are not provided by the system. This is usually expressed via
dependency(..., fallback: ...).
2. To download and build 'copylibs' which are meant to be used by
copying into your project. This is always done with an explicit
subproject() call.
--wrap-mode=nofallback will never do (1)
--wrap-mode=nodownload will do neither (1) nor (2)
If you are building from a release tarball, you should be able to
safely use 'nodownload' since upstream is expected to ship all
required sources with the tarball.
If you are building from a git repository, you will want to use
'nofallback' so that any 'copylib' wraps will be download as
subprojects.
Note that these options do not affect subprojects that are git
submodules since those are only usable in git repositories, and you
almost always want to download them.
This will benefit projects such as GNOME Recipes that prefer using
submodules over wraps because it's easier to maintain since git is
aware of it, and because it integrates with their existing
workflow. Without this, these projects have to manually initialize
the submodules which is completely unnecessary.
Closes https://github.com/mesonbuild/meson/issues/1449
The same substitutions and rules as custom_target().
Also generally fix it to actually work when run in a subdir and with
anything other than absolute paths for input and output files.
We now also log a message when configuring files.
Includes tests for all this.
Otherwise env is {} and we get a traceback trying to use the setup:
$ /home/cassidy/dev/meson/mesontest.py -C build --setup valgrind
ninja: Entering directory `/home/cassidy/dev/gst/master/gst-build/build'
ninja: no work to do.
Traceback (most recent call last):
File "/home/cassidy/dev/meson/mesontest.py", line 579, in <module>
sys.exit(run(sys.argv[1:]))
File "/home/cassidy/dev/meson/mesontest.py", line 575, in run
return th.doit()
File "/home/cassidy/dev/meson/mesontest.py", line 337, in doit
self.run_tests(tests)
File "/home/cassidy/dev/meson/mesontest.py", line 485, in run_tests
self.drain_futures(futures, logfile, jsonlogfile)
File "/home/cassidy/dev/meson/mesontest.py", line 504, in drain_futures
self.print_stats(numlen, tests, name, result.result(), i, logfile, jsonlogfile)
File "/usr/lib64/python3.5/concurrent/futures/_base.py", line 398, in result
return self.__get_result()
File "/usr/lib64/python3.5/concurrent/futures/_base.py", line 357, in __get_result
raise self._exception
File "/usr/lib64/python3.5/concurrent/futures/thread.py", line 55, in run
result = self.fn(*self.args, **self.kwargs)
File "/home/cassidy/dev/meson/mesontest.py", line 216, in run_single_test
child_env.update(self.options.global_env.get_env(child_env))
AttributeError: 'dict' object has no attribute 'get_env'
There is no harm in doing this, and this is the simplest fix for this.
Closes https://github.com/mesonbuild/meson/issues/1371
Ever since we changed how we do library searching, the full path to the
library has not been available under `.fullpath`. This has been broken
for at least a year...
And actually test that prog.path() works. The earlier test was just
running the command without checking if it succeeded.
Also make everything use prog.get_command() or get_path() instead of
accessing the internal member prog.fullpath directly.
With the 'install_mode' kwarg, you can now specify the file and
directory permissions and the owner and the group to be used while
installing. You can pass either:
* A single string specifying just the permissions
* A list of strings with:
- The first argument a string of permissions
- The second argument a string specifying the owner or
an int specifying the uid
- The third argument a string specifying the group or
an int specifying the gid
Specifying `false` as any of the arguments skips setting that one.
The format of the permissions kwarg is the same as the symbolic
notation used by ls -l with the first character that specifies 'd',
'-', 'c', etc for the file type omitted since that is always obvious
from the context.
Includes unit tests for the same. Sadly these only run on Linux right
now, but we want them to run on all platforms. We do set the mode in the
integration tests for all platforms but we don't check if they were
actually set correctly.
Jussi Pakkanen
Dylan Baker
Nirbheek Chauhan
Matthias Klumpp
Elliott Sales de Andrade
Philipp Ittershagen
Tim-Philipp Müller
Thibault Saunier
Haakon Sporsheim
Dima Krasner
Mike Sinkovsky
Hemmo Nieminen