Re: [PATCH v3 3/4] meson: add support for 'hdr-check'

> Hi Karthik
>
> On 14/04/2025 22:16, 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
>> resembles that of the Makefile and provides the same check.
>>
>> Since meson builds are out-of-tree, header dependencies are not
>> automatically met. So unlike the Makefile version, we also need to add
>> the required dependencies.
>>
>> Also add the 'xdiff/' dir to the list of 'third_party_sources' as those
>> headers must be skipped from the checks too!
>
> Doesn't this mean we'll skip all the xdiff files when running coccinelle
> as well? If so the commit message should point that out and explain why
> that is an improvement.
>

>> +exclude_from_check_headers = generated_headers
>
> I'm not sure this is necessary. The list of headers that we filter is
> generated with "git ls-files" and so wont contain generated headers in
> the first place.
>

>> +exclude_from_check_headers += [
>> +  'compat/',
>> +  'unicode-width.h',
>> +]
>> +
>> +if sha1_backend != 'openssl'
>> +  exclude_from_check_headers += 'sha1/openssl.h'
>> +endif
>> +if sha256_backend != 'openssl'
>> +  exclude_from_check_headers += 'sha256/openssl.h'
>> +endif
>> +if sha256_backend != 'nettle'
>> +  exclude_from_check_headers += 'sha256/nettle.h'
>> +endif
>> +if sha256_backend != 'gcrpyt'
>> +  exclude_from_check_headers += 'sha256/gcrypt.h'
>> +endif
>> +
>> +if git.found() and compiler.get_argument_syntax() == 'gcc'
>> +  hco_targets = []
>> +  foreach h : headers
>> +    skip_header = false
>> +    foreach exclude : exclude_from_check_headers
>> +      if h.startswith(exclude)
>> +        skip_header = true
>> +        break
>> +      endif
>> +    endforeach
>
> This part looks much more maintainable than than the previous version
>

>
> Thanks
>
> Phillip
>
>> +    if skip_header
>> +      continue
>> +    endif
>> +
>> +    hcc = custom_target(
>> +      input: h,
>> +      output: h.underscorify() + 'cc',
>> +      command: [
>> +        shell,
>> +        '-c',
>> +        'echo \'#include "git-compat-util.h"\' > @OUTPUT@ && echo \'#include "' + h + '"\' >> @OUTPUT@'
>> +      ]
>> +    )
>> +
>> +    hco = custom_target(
>> +      input: hcc,
>> +      output: fs.replace_suffix(h.underscorify(), '.hco'),
>> +      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(),