XC_VM/docs/en/guides/feature-flags.md

Development Feature Flags

XC_VM uses constants and settings-driven flags to control environment behavior.

Application constants are stored in src/Core/Config/AppConfig.php.

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Active Runtime Flag

PHP_ERRORS

define('PHP_ERRORS', $rShowErrors); // derived from $rSettings['debug_show_errors']

PHP_ERRORS controls PHP/debug verbosity and logger screen output:

Logger::init(PHP_ERRORS, LOGS_TMP_PATH . 'error_log.log');

DB_ACCESS_ENABLED

define('DB_ACCESS_ENABLED', false); // enables phpMiniAdmin tab/page in admin panel

DB_ACCESS_ENABLED controls access to phpMiniAdmin from admin UI only. It does not block core application database connections. Its companion DB_ACCESS_PWD (also in AppConfig.php) sets the password protecting that page — leave it empty to keep the tab off, set a strong value only while you need it.

DEV_MODE

define('DEV_MODE', false); // master development-mode flag

DEV_MODE is the compile-time development switch (bootstrap.php reads it into self::$devMode). When true it forces PHP_ERRORS on (verbose on-screen errors), surfaces reCAPTCHA diagnostics, and enables other developer conveniences.

⚠️ Never enable DEV_MODE or debug_show_errors on production — both expose internal errors/paths to visitors. PHP_ERRORS ends up true if either the DEV_MODE constant is set (bootstrap path) or the debug_show_errors setting is on (request-guard path); that is the resolution rule when the two overlap.

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Settings-driven Flags ($rSettings)

Loaded from settings cache and used in runtime decision points.

Key	Type	Meaning
debug_show_errors	bool	show detailed errors/debug output
recaptcha_enable	bool	enable reCAPTCHA v2 on login
verify_host	bool	enforce host allowlist validation
save_login_logs	bool	persist login attempts in login_logs

These values are loaded from CACHE_TMP_PATH/settings by request guards.

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Static App Constants

From src/Core/Config/AppConfig.php:

define('DB_ACCESS_ENABLED', false);
define('DB_ACCESS_PWD', '');       // password for the phpMiniAdmin tab (empty = off)
define('DEV_MODE', false);         // master development-mode switch
define('XC_VM_VERSION', '2.4.1');  // bumped every release — treat as illustrative
define('GIT_OWNER', 'Vateron-Media');
define('GIT_REPO_MAIN', 'XC_VM');
define('GIT_REPO_UPDATE', 'XC_VM_Update');
define('GIT_REPO_BIN', 'XC_VM_Binaries');
define('GIT_REPO_FANOUT', 'XC_VM_Fanout'); // xc_fanout daemon source + binaries
define('GIT_REPO_PROXY', 'XC_VM_Proxy');
define('MONITOR_CALLS', 3);
define('OPENSSL_EXTRA', '...');

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Adding New Flags

Use static constants in AppConfig.php for fixed infrastructure/runtime constants (edited in code, take effect on next request). Use settings ($rSettings) for values an operator toggles from the admin panel (Settings page) — those are persisted in the settings DB table and read from CACHE_TMP_PATH/settings.

Avoid defining the same behavior in both places. When they unavoidably overlap (as with DEV_MODE vs debug_show_errors → PHP_ERRORS), the effective value is the OR of the two — either turning it on wins.

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Related files

File	Purpose
src/Core/Config/AppConfig.php	static app constants
src/Core/Http/RequestGuard.php	loads $rSettings, sets PHP_ERRORS
src/Core/Error/ErrorHandler.php	uses debug_show_errors behavior
src/Core/Logging/Logger.php	debug/verbosity behavior