[libcamera-devel] [PATCH 2/2] meson: Define python3 and python3-yaml required dependencies

[Laurent Pinchart]

Hi Ezequiel,

On Mon, Nov 18, 2019 at 08:54:43PM +0200, Laurent Pinchart wrote:
> On Mon, Nov 18, 2019 at 09:14:10AM -0300, Ezequiel Garcia wrote:
> > On Mon, 2019-11-18 at 02:26 +0200, Laurent Pinchart wrote:
> >> On Fri, Nov 15, 2019 at 12:23:42PM -0300, Ezequiel Garcia wrote:
> >>> With this change, meson will complain specifically about missing
> >>> python3 and missing python3-yaml. As specified by meson
> >>> documentation: https://mesonbuild.com/Python-module.html,
> >>> this change requires meson v0.51.
> > 
> > How about this
> > 
> > +# meson v0.51 is too new and not distributed
> > +# by major distros. Let's take advantage of it
> > +# optionally.
> > +if meson.version().version_compare('>=0.51')
> > +    py_mod = import('python')
> > +    py_inst = py_mod.find_installation('python3', modules: ['yaml'])
> 
> Do you need to assign the return value to a variable ?
> 
> > +endif
> > +
> > 
> > ?
> > 
> > Just to get the thing documented, we can drop the ifs
> > once libcamera requires meson 0.51
> 
> That looks better to me, but should be conditioned to the documentation
> option being enabled.

Scratch this, I got it mixed in my head. This is unrelated to
documentation. Your proposal looks good. We may want to already prepare
for additional modules with something along the lines of

/meson.build:

# Towards the beginning

py_modules = []

...

# Towards the end

if meson.version().version_compare('>=0.51')
    py_mod = import('python')
    py_mod.find_installation('python3', modules: py_modules)
endif

/src/libcamera/meson.build:

...
py_modules += ['yaml']
...

but that could also be done later.

> >> Neither Debian stable nor Ubuntu stable ship meson v0.51 or newer, so I
> >> think this is a too strict requirement. There are useful features in
> >> newer meson verions, but we want to keep libcamera easily buildable on
> >> common distributions.
> >> 
> >>> Signed-off-by: Ezequiel Garcia <ezequiel at collabora.com>
> >>> ---
> >>>  meson.build               | 2 +-
> >>>  src/libcamera/meson.build | 3 +++
> >>>  2 files changed, 4 insertions(+), 1 deletion(-)
> >>> 
> >>> diff --git a/meson.build b/meson.build
> >>> index 72ad7c8b493b..38c0f1d55b56 100644
> >>> --- a/meson.build
> >>> +++ b/meson.build
> >>> @@ -1,5 +1,5 @@
> >>>  project('libcamera', 'c', 'cpp',
> >>> -    meson_version : '>= 0.40',
> >>> +    meson_version : '>= 0.51',
> >>>      version : '0.0.0',
> >>>      default_options : [
> >>>          'werror=true',
> >>> diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
> >>> index afbca76968f9..509499359cdb 100644
> >>> --- a/src/libcamera/meson.build
> >>> +++ b/src/libcamera/meson.build
> >>> @@ -61,6 +61,9 @@ if libudev.found()
> >>>      ])
> >>>  endif
> >>>  
> >>> +py_mod = import('python')
> >>> +py_inst = py_mod.find_installation('python3', modules: ['yaml'])
> >>> +
> >>>  gen_controls = files('gen-controls.py')
> >>>  
> >>>  control_ids_cpp = custom_target('control_ids_cpp',

-- 
Regards,

Laurent Pinchart