ma27 send me here, because i bothered him about a failing php build on my machine. (I silenced it by disabling the failing test, so no worries for me ;)) Just to give you a heads up notice in case you are interested...

alab /ws/nixpkgs  master (a7cf937) took 1m58s
% nix-shell -I nixpkgs=/ws/nixpkgs -p 'php.withExtensions ({ fileinfo }: [ fileinfo ])'

is failing with

=====================================================================
TEST RESULT SUMMARY
---------------------------------------------------------------------
Exts skipped    :    0
Exts tested     :   12
---------------------------------------------------------------------

Number of tests :   52                47
Tests skipped   :    5 (  9.6%) --------
Tests warned    :    0 (  0.0%) (  0.0%)
Tests failed    :    1 (  1.9%) (  2.1%)
Tests passed    :   46 ( 88.5%) ( 97.9%)
---------------------------------------------------------------------
Time taken      :    1 seconds
=====================================================================

=====================================================================
FAILED TEST SUMMARY
---------------------------------------------------------------------
Bug #68996 (Invalid free of CG(interned_empty_string)) [tests/bug68996.phpt]
=====================================================================

You may have found a problem in PHP.
This report can be automatically sent to the PHP QA team at
http://qa.php.net/reports and http://news.php.net/php.qa.reports
This gives us a better understanding of PHP's behavior.
If you don't want to send the report immediately you can choose
option "s" to save it.  You can then email it to qa-reports@lists.php.net later.
Do you want to send this report now? [Yns]:
Please enter your email address.
(Your address will be mangled so that it will not go out on any
mailinglist in plain text):
Warning: fsockopen(): php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution in /build/php-8.0.18/ext/fileinfo/run-tests.php on line 1152

Warning: fsockopen(): Unable to connect to qa.php.net:80 (php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution) in /build/php-8.0.18/ext/fileinfo/run-tests.php on line 1152

The test script was unable to automatically send the report to PHP's QA Team
Please send /build/php-8.0.18/ext/fileinfo/php_test_results_20220415_1558.txt to qa-reports@lists.php.net manually, thank you.
make: *** [Makefile:131: test] Error 1
error: builder for '/nix/store/i8bx7mhkz4aiggcy3r62l32k543gfhgx-php-fileinfo-8.0.18.drv' failed with exit code 2;
       last 10 log lines:
       > Please enter your email address.
       > (Your address will be mangled so that it will not go out on any
       > mailinglist in plain text):
       > Warning: fsockopen(): php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution in /build/php-8.0.18/ext/fileinfo/run-tests.php on line 1152
       >
       > Warning: fsockopen(): Unable to connect to qa.php.net:80 (php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution) in /build/php-8.0.18/ext/fileinfo/run-tests.php on line 1152
       >
       > The test script was unable to automatically send the report to PHP's QA Team
       > Please send /build/php-8.0.18/ext/fileinfo/php_test_results_20220415_1558.txt to qa-reports@lists.php.net manually, thank you.
       > make: *** [Makefile:131: test] Error 1
       For full logs, run 'nix log /nix/store/i8bx7mhkz4aiggcy3r62l32k543gfhgx-php-fileinfo-8.0.18.drv'.
error: 1 dependencies of derivation '/nix/store/5slqm7ls3kay78d2gmsjyvxbia37xylg-php-extra-init-8.0.18.ini.drv' failed to build
error: 1 dependencies of derivation '/nix/store/11s7w77n3f07nagnfzlvyjpk61j2p2l2-php-with-extensions-8.0.18.drv' failed to bu

1. Create a composer.json file in a random dir
2. The content of it should be:

{
    "name": "pol/foo",
    "require": {
        "ext-fileinfo": "*"
    }
}

1. Run: nix develop github:loophp/nix-shell#php80 --impure in the same directory