On Fri, Sep 5, 2025 at 3:25 AM Paolo Bonzini <pbonz...@redhat.com> wrote:
> On 9/4/25 17:11, Peter Foley wrote:
> > Relying on `python3` to be avilable in $PATH doesn't work in some build
> > environments. Update the build files to use the found python binary
> > explicitly.
>
> Meson already does this, if the file is not executable. See
> docs/devel/build-system.rst:
>
> Meson has a special convention for invoking Python scripts: if their
> first line is ``#! /usr/bin/env python3`` and the file is *not*
> executable, find_program() arranges to invoke the script under the
> same Python interpreter that was used to invoke Meson. This is the
> most common and preferred way to invoke support scripts from Meson
> build files, because it automatically uses the value of configure's
> --python= option.
>
> Using "[python, 'foo']" is only needed for scripts "where it is
> desirable to make the script executable (for example for test scripts
> that developers may want to invoke from the command line, such as
> tests/qapi-schema/test-qapi.py)".
>
Interesting, that's not what I'm seeing in practice.
For example, locally reverting the change to block/meson.build results in:
FAILED: block/module_block.h
/build/work/046b6fd7014012220d3de53b1bd62f6eb1e9/google3/third_party/qemu/block/../scripts/modules/module_block.py
block/module_block.h
/usr/bin/env: 'python3': No such file or directory
Where module_block.py is *not* executable:
-rw-rw-r-- 1 pefoley primarygroup 2751 Feb 10 2021
third_party/qemu/scripts/modules/module_block.py
>
> I think the only file you touched that is executable is
> scripts/qemu-plugin-symbols.py; so your issue can be fixed without code
> changes, and with a patch that only does "chmod -x
> scripts/qemu-plugin-symbols.py". Please correct me if I'm wrong though!
>
> Thanks,
>
> Paolo
>
> > Signed-off-by: Peter Foley <pefo...@google.com>
> > ---
> > block/meson.build | 6 ++----
> > meson.build | 10 +++++-----
> > plugins/meson.build | 2 +-
> > 3 files changed, 8 insertions(+), 10 deletions(-)
> >
> > diff --git a/block/meson.build b/block/meson.build
> > index
> 34b1b2a30630214959630d5543181bc82a54d2b3..67e9bee1210307ff15ca87ba0f5e7f785df15042
> 100644
> > --- a/block/meson.build
> > +++ b/block/meson.build
> > @@ -139,14 +139,12 @@ if get_option('dmg').allowed()
> > endforeach
> > endif
> >
> > -module_block_py = find_program('../scripts/modules/module_block.py')
> > module_block_h = custom_target('module_block.h',
> > output: 'module_block.h',
> > input: modsrc,
> > - command: [module_block_py, '@OUTPUT0@',
> modsrc])
> > + command: [python,
> files('../scripts/modules/module_block.py'), '@OUTPUT0@', modsrc])
> > block_ss.add(module_block_h)
> >
> > -wrapper_py = find_program('../scripts/block-coroutine-wrapper.py')
> > block_gen_c = custom_target('block-gen.c',
> > output: 'block-gen.c',
> > input: files(
> > @@ -158,7 +156,7 @@ block_gen_c = custom_target('block-gen.c',
> >
> '../include/system/block-backend-io.h',
> > 'coroutines.h'
> > ),
> > - command: [wrapper_py, '@OUTPUT@', '@INPUT@
> '])
> > + command: [python,
> files('../scripts/block-coroutine-wrapper.py'), '@OUTPUT@', '@INPUT@'])
> > block_ss.add(block_gen_c)
> >
> > block_ss.add(files('stream.c'))
> > diff --git a/meson.build b/meson.build
> > index
> fa6186db33435c26d06dce2971a9f536250607e0..6e8baf3deb13c172eecd371ea302b1c2539048d0
> 100644
> > --- a/meson.build
> > +++ b/meson.build
> > @@ -12,8 +12,6 @@ add_test_setup('slow', exclude_suites: ['thorough'],
> > add_test_setup('thorough',
> > env: ['G_TEST_SLOW=1', 'SPEED=thorough',
> 'RUST_BACKTRACE=1'])
> >
> >
> -meson.add_postconf_script(find_program('scripts/symlink-install-tree.py'))
> > -
> > ####################
> > # Global variables #
> > ####################
> > @@ -76,6 +74,8 @@ have_user = have_linux_user or have_bsd_user
> > sh = find_program('sh')
> > python = import('python').find_installation()
> >
> > +meson.add_postconf_script([python, 'scripts/symlink-install-tree.py'])
> > +
> > cc = meson.get_compiler('c')
> > all_languages = ['c']
> > if host_os == 'windows' and add_languages('cpp', required: false,
> native: false)
> > @@ -3474,7 +3474,7 @@ foreach target : target_dirs
> > output: config_devices_mak,
> > depfile: config_devices_mak + '.d',
> > capture: true,
> > - command: [minikconf,
> > + command: [python, minikconf,
> > get_option('default_devices') ? '--defconfig' :
> '--allnoconfig',
> > config_devices_mak, '@DEPFILE@', '@INPUT@',
> > host_kconfig, target_kconfig])
> > @@ -3545,8 +3545,8 @@ config_host_h = configure_file(output:
> 'config-host.h', configuration: config_ho
> > genh += config_host_h
> >
> > hxtool = find_program('scripts/hxtool')
> > -shaderinclude = find_program('scripts/shaderinclude.py')
> > -qapi_gen = find_program('scripts/qapi-gen.py')
> > +shaderinclude = [python, 'scripts/shaderinclude.py']
> > +qapi_gen = [python, 'scripts/qapi-gen.py']
> > qapi_gen_depends = [ meson.current_source_dir() /
> 'scripts/qapi/__init__.py',
> > meson.current_source_dir() /
> 'scripts/qapi/commands.py',
> > meson.current_source_dir() /
> 'scripts/qapi/common.py',
> > diff --git a/plugins/meson.build b/plugins/meson.build
> > index
> 62c991d87fcdd8bcde8edddcc73909c6133f5460..6bf72a69060414ba1b7c1857515eeceb5a2c7b7c
> 100644
> > --- a/plugins/meson.build
> > +++ b/plugins/meson.build
> > @@ -6,7 +6,7 @@ qemu_plugin_symbols = configure_file(
> > input: files('../include/qemu/qemu-plugin.h'),
> > output: 'qemu-plugin.symbols',
> > capture: true,
> > - command: [files('../scripts/qemu-plugin-symbols.py'), '@INPUT@'])
> > + command: [python, files('../scripts/qemu-plugin-symbols.py'), '@INPUT@
> '])
> >
> > # Modules need more symbols than just those in
> plugins/qemu-plugins.symbols
> > if not enable_modules
> >
> > ---
> > base-commit: baa79455fa92984ff0f4b9ae94bed66823177a27
> > change-id: 20250904-python-78ccebd0fded
> >
> > Best regards,
>
>
