[libcamera-devel] [RFC 1/1] build: Preserve upstream git versioning using meson dist

Wed Oct 13 12:52:05 CEST 2021

Hi Laurent,

Thank you for your feedback.

On Wed, 13 Oct 2021 at 11:38, Laurent Pinchart <
laurent.pinchart at ideasonboard.com> wrote:

> Hi Naush,
>
> Thank you for the patch.
>
> On Wed, Oct 13, 2021 at 11:20:53AM +0100, Naushir Patuck wrote:
> > On Wed, 13 Oct 2021 at 11:19, Naushir Patuck wrote:
> > > When distributions build and package libcamera libraries, they may not
> > > necessarily run the build in the upstream source tree. In these cases,
> the git
> > > SHA1 versioning information will be lost.
> > >
> > > This change addresses that problem by requiring package managers to run
> > > 'meson dist' to create a tarball of the source files and build from
> there.
> > > On runing 'meson dist', the utils/run-dist.sh script will create a
> version.gen
> > > file in the release tarball with the version string generated from the
> existing
> > > utils/gen-version.sh script.
> > >
> > > The build system has been updated to check for the presence of this
> version.gen
> > > file and read the version string from it. If the file is not present,
> the
> > > version string is generated by running utils/gen-version.sh as it
> currently
> > > does.
> > >
> > > Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> > > ---
> > >  meson.build               | 30 ++++++++++++++++++++----------
> > >  src/libcamera/meson.build | 11 +++++------
> > >  utils/run-dist.sh         |  9 +++++++++
> > >  3 files changed, 34 insertions(+), 16 deletions(-)
> > >  create mode 100644 utils/run-dist.sh
> > >
> > > diff --git a/meson.build b/meson.build
> > > index a49c484fe64e..f27bfd479a5c 100644
> > > --- a/meson.build
> > > +++ b/meson.build
> > > @@ -10,20 +10,30 @@ project('libcamera', 'c', 'cpp',
> > >      ],
> > >      license : 'LGPL 2.1+')
> > >
> > > -# Generate version information. The libcamera_git_version variable
> contains the
> > > -# full version with git patch count and SHA1 (e.g.
> 1.2.3+211-c94a24f4), while
> > > -# the libcamera_version variable contains the major.minor.patch (e.g.
> 1.2.3)
> > > -# only. If the source tree isn't under git control, or if it matches
> the last
> > > -# git version tag, the build metadata (e.g. +211-c94a24f4) is omitted
> from
> > > -# libcamera_git_version.
> > > -libcamera_git_version = run_command('utils/gen-version.sh',
> > > -
> meson.build_root()).stdout().strip()
> > > -if libcamera_git_version == ''
> > > -    libcamera_git_version = meson.project_version()
> > > +fs_mod = import('fs')
> > > +if not fs_mod.is_file('version.gen')
> > > +    # Generate version information. The libcamera_git_version
> variable contains the
> > > +    # the full version with git patch count and SHA1 (e.g.
> 1.2.3+211-c94a24f4), while
> > > +    # the libcamera_version variable contains the major.minor.patch
> (e.g. 1.2.3)
> > > +    # only. If the source tree isn't under git control, or if it
> matches the last
> > > +    # git version tag, the build metadata (e.g. +211-c94a24f4) is
> omitted from
> > > +    # libcamera_git_version.
> > > +    libcamera_git_version = run_command('utils/gen-version.sh',
> > > +
> meson.build_root()).stdout().strip()
> > > +    if libcamera_git_version == ''
> > > +        libcamera_git_version = meson.project_version()
> > > +    endif
> > > +else
> > > +    # Read the version information from the file generated by the
> utils/run-dist.sh
> > > +    # script on a 'meson dist' command.
> > > +    libcamera_git_version = run_command(['cat',
> 'version.gen']).stdout().strip()
> > >  endif
> >
> > I've added an if clause here to check for the presence of the version
> file, but I
> > could equally leave this as-is and check for the file in gen-version.sh.
> I don't have
> > a strong preference either way.
>
> I think I'd prefer handling this in gen-version.sh, as it will
> centralize all the version handling code in a single place.
>

Ok, will do.

>
> > >  libcamera_version = libcamera_git_version.split('+')[0]
> > >
> > > +# This script gererates the version.gen file on a 'meson dist'
> command.
> > > +meson.add_dist_script('utils/run-dist.sh')
> > > +
> > >  # Configure the build environment.
> > >  cc = meson.get_compiler('c')
> > >  cxx = meson.get_compiler('cpp')
> > > diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
> > > index 243dd3c180eb..360eaf80ecf1 100644
> > > --- a/src/libcamera/meson.build
> > > +++ b/src/libcamera/meson.build
> > > @@ -93,12 +93,11 @@ endforeach
> > >
> > >  libcamera_sources += control_sources
> > >
> > > -gen_version = meson.source_root() / 'utils' / 'gen-version.sh'
> > > -
> > > -version_cpp = vcs_tag(command : [gen_version, meson.build_root()],
> > > -                      input : 'version.cpp.in',
> > > -                      output : 'version.cpp',
> > > -                      fallback : meson.project_version())
> > > +version_data = configuration_data()
> > > +version_data.set('VCS_TAG', libcamera_git_version)
> > > +version_cpp = configure_file(input : 'version.cpp.in',
> > > +                             output : 'version.cpp',
> > > +                             configuration : version_data)
> > >
> > >  libcamera_sources += version_cpp
> > >
> > > diff --git a/utils/run-dist.sh b/utils/run-dist.sh
> > > new file mode 100644
> > > index 000000000000..1b2a6348c6bc
> > > --- /dev/null
> > > +++ b/utils/run-dist.sh
> > > @@ -0,0 +1,9 @@
> > > +#!/bin/sh
> > > +
> > > +# SPDX-License-Identifier: GPL-2.0-or-later
> > > +#
> > > +# On a meson dist run, generate the version string and store it in a
> file.
> > > +# This will late be picked up by the build system and used in place
> of running
>
> s/late/later/
>
> > > +# the utils/gen-version.sh script again since we may not be running
> in the
> > > +# upstream git source tree, and so version information would be lost.
>
> A blank line here would be nice.
>
> > > +"$MESON_DIST_ROOT"/utils/gen-version.sh >
> "$MESON_DIST_ROOT"/version.gen
>
> Do we need to cd to MESON_SOURCE_ROOT first (or set GIT_DIR), or is
> there a guarantee that this script will always run from a subdirectory
> of MESON_SOURCE_ROOT ?
>

>From what I can tell, meson dist does not seem to allow the user to specify
the dist output directory,
it creates a 'meson-dist' direcotry under MESON_BUILD_ROOT. I had assumed
the latter will
will always be a subdirectly of MESON_SOURCE_ROOT, but perhaps that will
not always be the
case, so I could cd MESON_SOURCE_ROOT to be sure!

>
> To end with some nitpicking, I wonder if there's a standard name for
> files containing a version number (I initially thought about .version
> but have no evidence that it would be better than version.gen).
>

I don't know of any specific standard filename for this.  I chose the .gen
extension to loosely signify
that this was an auto generated file.  I can change to .version if you
prefer?

Regards,
Naush

>
> --
> Regards,
>
> Laurent Pinchart
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.libcamera.org/pipermail/libcamera-devel/attachments/20211013/14b15a9b/attachment.htm>