Subject: Re: [PATCH v2 3/4] meson: add support for 'hdr-check'

From: Patrick Steinhardt <[email-masked]>
Date: Fri, 11 Apr 2025 12:06:54 +0200

On Thu, Apr 10, 2025 at 01:30:33PM +0200, Karthik Nayak wrote:
> The Makefile supports a target called 'hdr-check', which checks if
> individual header files can be independently compiled. Let's port this
> functionality to meson, our new build system too. The implementation

Nit: Meson is typically spelt with an upper-case 'M'.

> resembles that of the Makefile and provides the same check.
> 
> Signed-off-by: Karthik Nayak <[email-masked]>
> ---
>  meson.build | 107 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 107 insertions(+)
> 
> diff --git a/meson.build b/meson.build
> index 790d178007..6fce1aa618 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -655,6 +655,12 @@ if git.found()
>    endforeach
>  endif
>  
> +headers_generated = [
> +  'command-list.h',
> +  'config-list.h',
> +  'hook-list.h'
> +]
> +
>  if not get_option('breaking_changes')
>    builtin_sources += 'builtin/pack-redundant.c'
>  endif
> @@ -1995,6 +2001,107 @@ endif
>  
>  subdir('contrib')
>  
> +headers_check_exclude = headers_generated
> +headers_check_exclude += [
> +  'compat/apple-common-crypto.h',
> +  'compat/bswap.h',
> +  'compat/compiler.h',
> +  'compat/disk.h',
> +  'compat/fsmonitor/fsm-darwin-gcc.h',
> +  'compat/fsmonitor/fsm-health.h',
> +  'compat/fsmonitor/fsm-listen.h',
> +  'compat/mingw.h',
> +  'compat/msvc.h',
> +  'compat/nedmalloc/malloc.c.h',
> +  'compat/nedmalloc/nedmalloc.h',
> +  'compat/nonblock.h',
> +  'compat/obstack.h',
> +  'compat/poll/poll.h',
> +  'compat/precompose_utf8.h',
> +  'compat/regex/regex.h',
> +  'compat/regex/regex_internal.h',
> +  'compat/sha1-chunked.h',
> +  'compat/terminal.h',
> +  'compat/vcbuild/include/sys/param.h',
> +  'compat/vcbuild/include/sys/time.h',
> +  'compat/vcbuild/include/sys/utime.h',
> +  'compat/vcbuild/include/unistd.h',
> +  'compat/vcbuild/include/utime.h',
> +  'compat/win32.h',
> +  'compat/win32/alloca.h',
> +  'compat/win32/dirent.h',
> +  'compat/win32/lazyload.h',
> +  'compat/win32/path-utils.h',
> +  'compat/win32/pthread.h',
> +  'compat/win32/syslog.h',
> +  'compat/zlib-compat.h',
> +  't/unit-tests/clar/clar.h',
> +  't/unit-tests/clar/clar/fixtures.h',
> +  't/unit-tests/clar/clar/fs.h',
> +  't/unit-tests/clar/clar/print.h',
> +  't/unit-tests/clar/clar/sandbox.h',
> +  't/unit-tests/clar/clar/summary.h',
> +  't/unit-tests/clar/test/clar_test.h',
> +  'unicode-width.h',
> +  'xdiff/xdiff.h',
> +  'xdiff/xdiffi.h',
> +  'xdiff/xemit.h',
> +  'xdiff/xinclude.h',
> +  'xdiff/xmacros.h',
> +  'xdiff/xprepare.h',
> +  'xdiff/xtypes.h',
> +  'xdiff/xutils.h',
> +]

Many of these feel as if they should've been part of
`third_party_sources`.

> +if sha1_backend != 'openssl'
> +  headers_check_exclude += 'sha1/openssl.h'
> +endif
> +if sha256_backend != 'openssl'
> +  headers_check_exclude += 'sha256/openssl.h'
> +endif
> +if sha256_backend != 'nettle'
> +  headers_check_exclude += 'sha256/nettle.h'
> +endif
> +if sha256_backend != 'gcrpyt'
> +  headers_check_exclude += 'sha256/gcrypt.h'
> +endif
> +
> +if headers.length() != 0 and compiler.get_argument_syntax() == 'gcc'
> +  hco_targets = []
> +  foreach h : headers
> +    if headers_check_exclude.contains(h)
> +      continue
> +    endif
> +
> +    hcc = custom_target(
> +      input: h,
> +      output: h.underscorify() + 'cc',
> +      command: [
> +        shell,
> +        '-c',
> +        'echo \'#include "git-compat-util.h"\' > @OUTPUT@ && echo -n \'#include "' + h + '"\' >> @OUTPUT@'
> +      ]
> +    )
> +
> +    hco = custom_target(
> +      input: hcc,
> +      output: h.underscorify().replace('.h', '.hco'),

You can use `fs.replace_suffix()` instead of `.replace()`.

> +      command: [
> +        compiler.cmd_array(),
> +        libgit_c_args,
> +        '-I', meson.project_source_root(),
> +        '-I', meson.project_source_root() / 't/unit-tests',
> +        '-o', '/dev/null',
> +        '-c', '-xc',
> +        '@INPUT@'
> +      ]
> +    )
> +    hco_targets += hco
> +  endforeach
> +
> +  alias_target('hdr-check', hco_targets)
> +endif
> +
>  foreach key, value : {
>    'DIFF': diff.full_path(),
>    'GIT_SOURCE_DIR': meson.project_source_root(),

Patrick