This adds new selectize and selectizeField macros to _includes/forms, which make it easier to create Selectize-based select menus. These support an includeEnvVars setting, which can be set to true to include any defined environment variables which are set to one of the available option values.

{{ forms.selectizeField({
    label: "Encryption Method",
    id: 'encryptionMethod',
    name: 'encryptionMethod',
    options: [
        { value: 'none', label: "None"|t('app') },
        { value: 'ssl', label: "SSL"|t('app') },
        { value: 'tls', label: "TLS"|t('app') }
    ],
    includeEnvVars: true,
    value: adapter.encryptionMethod ?: 'none',
    errors: adapter.getErrors('encryptionMethod'),
}) }}

There’s also new booleanMenu and booleanMenuField macros, which extend selectize/selectizeField for cases where a boolean value is needed. Their options are “Yes” (0) and “No” (1), and support yesLabel and noLabel settings to override the labels.

When includeEnvVars is set to true, they will only include environment variables that are set to a boolean-esque value: on, off, yes, no, true, false, 1, or 0 (case insensitive).

{{ forms.booleanMenuField({
    label: "System Status"|t('app'),
    warning: (craft.app.config.general.isSystemLive is same as(true) or craft.app.config.general.isSystemLive is same as(false) ? configWarning('isSystemLive')),
    id: 'live',
    name: 'live',
    yesLabel: 'Online'|t('app'),
    noLabel: 'Offline'|t('app'),
    includeEnvVars: true,
    value: system.live
}) }}

There’s also a new Craft::parseBooleanEnv() method, which should be used to normalize a boolean menu’s value to true or false at runtime (but that normalized value should not be stored, as we don’t want to lose the original environment variable name).

The following settings have been updated to support environment variables:

• General → System Status
• General → Time Zone
• Email → Encryption Method (SMTP transport type)

Resolves #8866
Resolves #8989
Possibly alleviates #9855