From: Martin Storsjö <martin@martin.st>
Date: Fri, 01 Aug 2025 09:42:52 GMT
Subject: Re: [PATCH v2] meson: Tolerate errors from git ls-files --deduplicate
Message-ID: <226b2a31-6220-4a4e-d0bf-3ad80c3be9a@martin.st>
In-Reply-To: <aIyHoF70z0jV-sj8@pks.im>

On Fri, 1 Aug 2025, Patrick Steinhardt wrote:

> On Fri, Aug 01, 2025 at 10:56:22AM +0300, Martin Storsjö wrote:
>> index 9bc1826cb6..9b519e6eed 100644
>> --- a/meson.build
>> +++ b/meson.build
>> @@ -694,9 +694,12 @@ third_party_excludes = [
>>
>>  headers_to_check = []
>>  if git.found() and fs.exists(meson.project_source_root() / '.git')
>> -  foreach header : run_command(git, '-C', meson.project_source_root(), 'ls-files', '--deduplicate', '*.h', third_party_excludes, check: true).stdout().split()
>> -    headers_to_check += header
>> -  endforeach
>> +  ls_headers = run_command(git, '-C', meson.project_source_root(), 'ls-files', '--deduplicate', '*.h', third_party_excludes, check: false)
>> +  if ls_headers.returncode() == 0
>> +    foreach header : ls_headers.stdout().split()
>> +      headers_to_check += header
>> +    endforeach
>> +  endif
>>  endif
>
> Yup, this looks reasonable to me. We could have an `else` branch that
> warns about the command failing, for example like this:
>
>    warning("could not find headers: " + ls_headers.stderr())

This would work - however the output from ls_headers.stderr() is fairly 
long (if you try running e.g. "git ls-files --foobar", you'll get a 37 
line listing of potential options); it's rather distracting for what's 
otherwise a fairly minor build configuration issue.

Using ls_headers.stderr().split('\n')[0] works and just gets us this:

     ../meson.build:703: WARNING: could not find headers: error: unknown option `deduplicate'

However I wonder if it's worth it, or if it just makes the meson file 
potentially more brittle? (E.g. what if split() returns an array of 0 
elements? Not sure if that's possible though...)

// Martin