Adding file_temp_path to settings

[shaal]

Per comment in https://www.drupal.org/project/drupal/releases/8.8.0, under "Other important update information".

The temporary file path is now a setting in settings.php, and is no longer stored in configuration. If your site is not using /tmp, you must update settings.php before running database updates:

$settings['file_temp_path'] = '/path/to/your/temporary/folder';

Original d.o issue: https://www.drupal.org/project/drupal/issues/3039026

[becw]

I think that this {$_ENV['TEMP']} environment variable is specific to Acquia (docs).

[shaal]

@becw should we add a specific tmp for every vendor (acquia / pantheon)?
Is there a better way to do it?

[becw]

Each vendor does their own handling of this, so I think that we can customize this behavior in the settings.*.php templates, rather than providing it as a setting (because then everybody would have to figure out how it should be set for whatever provider they're using). The temp directory is generally an absolute path, rather than a relative path like the public and private files directories, so it tends to be a bit more host-specific.

For example, Pantheon already handles the temp directory as part of its scaffolding: https://pantheon.io/docs/tmp

For Platform.sh, the temp directory is specified in the .platform.app.yaml file (/tmp), so we can use that.

Even the settings.build.php should be fine to hard-code it, since projects can edit that template as necessary (it's copied to each project at .the-build/drupal/settings.build.php).

[becw]

This is the right direction! We'll also need to cover the other config files.