run-tests.php: Remove extra env vars in the generated .sh file

[arnaud-lb]

run-tests.php conveniently generates a .sh file for each failed test.

The file starts by setting environment variables to the value they had during the test run.

Unfortunately, sometimes extra env vars will sneak in and prevent reproduction:

• Variables are inherited from the process that executes the .sh file
• The .sh file exports empty variables, but proc_open() does not
• When running under gdb, the variables LINES and COLUMNS are set

Here I ensure that these variables do not sneak in anymore in these cases when using the .sh file.

[arnaud-lb]

This removes any additional variable that may have been inherited from the parent process.

[staabm]

maybe your github.com comment should be a comment in the source for this magic sauce :)

[arnaud-lb]

Indeed :)

[arnaud-lb]

proc_open does not pass empty env vars, so if we export empty env vars here, the test will see these vars when running with the .sh file, but not when running it via run-tests.php.

[hakre]

@arnaud-lb: is that really proc_open()? for me proc_open() does empty vars fine. My guess is that 'unset $(env | cut -d= -f1)' does the actual trick here. Otherwise this would pretty much constitute a bug if not ... .

[arnaud-lb]

I had to double check, but yes I confirm that proc_open does not pass variables whose value is empty string: https://github.com/arnaud-lb/php-src/blob/484d528b40645f823047b53bcb5ba4228fb612c0/ext/standard/proc_open.c#L178

proc_open(
    [PHP_BINARY, '-n', '-r', 'var_dump(getenv());'],
    [],
    $pipes,
    env_vars: ['foo' => 'bar', 'not-passed' => ''],
);

// Output:

array(1) {
  ["foo"]=>
  string(3) "bar"
}

proc_open(
    'printenv',
    [],
    $pipes,
    env_vars: ['foo' => 'bar', 'not-passed' => ''],
);

// Output:

PWD=...
foo=bar
SHLVL=0
_=/usr/bin/printenv

[hakre]

Ah, that's the spot, here is how I did it working, should have probably posted that earlier, sigh:

$descriptor_spec = [];
$env   = ['TRUTH='];
$pipes = [];
$proc  = proc_open(['env'], $descriptor_spec, $pipes, null, $env);
$exit  = proc_close($proc);

output:

TRUTH=

Thanks for double checking @arnaud-lb, this clarifies the comment in the run-tests.php script for me, it depends on passing the $env_vars as list or associative.