Update config/constants.php with defined() checks

Allows for easier override with an environment-based configs.

Close #4045

3 files changed, 48 insertions, 34 deletions

diff --git a/application/config/constants.php b/application/config/constants.php
index 48283e223..e8d2c00ea 100644
--- a/application/config/constants.php
+++ b/application/config/constants.php
@@ -3,6 +3,18 @@ defined('BASEPATH') OR exit('No direct script access allowed');
 
 /*
 |--------------------------------------------------------------------------
+| Display Debug backtrace
+|--------------------------------------------------------------------------
+|
+| If set to TRUE, a backtrace will be displayed along with php errors. If
+| error_reporting is disabled, the backtrace will not display, regardless
+| of this setting
+|
+*/
+defined('SHOW_DEBUG_BACKTRACE') OR define('SHOW_DEBUG_BACKTRACE', TRUE);
+
+/*
+|--------------------------------------------------------------------------
 | File and Directory Modes
 |--------------------------------------------------------------------------
 |
@@ -14,10 +26,10 @@ defined('BASEPATH') OR exit('No direct script access allowed');
 | always be used to set the mode correctly.
 |
 */
-define('FILE_READ_MODE', 0644);
-define('FILE_WRITE_MODE', 0666);
-define('DIR_READ_MODE', 0755);
-define('DIR_WRITE_MODE', 0755);
+defined('FILE_READ_MODE')  OR define('FILE_READ_MODE', 0644);
+defined('FILE_WRITE_MODE') OR define('FILE_WRITE_MODE', 0666);
+defined('DIR_READ_MODE')   OR define('DIR_READ_MODE', 0755);
+defined('DIR_WRITE_MODE')  OR define('DIR_WRITE_MODE', 0755);
 
 /*
 |--------------------------------------------------------------------------
@@ -27,26 +39,14 @@ define('DIR_WRITE_MODE', 0755);
 | These modes are used when working with fopen()/popen()
 |
 */
-define('FOPEN_READ', 'rb');
-define('FOPEN_READ_WRITE', 'r+b');
-define('FOPEN_WRITE_CREATE_DESTRUCTIVE', 'wb'); // truncates existing file data, use with care
-define('FOPEN_READ_WRITE_CREATE_DESTRUCTIVE', 'w+b'); // truncates existing file data, use with care
-define('FOPEN_WRITE_CREATE', 'ab');
-define('FOPEN_READ_WRITE_CREATE', 'a+b');
-define('FOPEN_WRITE_CREATE_STRICT', 'xb');
-define('FOPEN_READ_WRITE_CREATE_STRICT', 'x+b');
-
-/*
-|--------------------------------------------------------------------------
-| Display Debug backtrace
-|--------------------------------------------------------------------------
-|
-| If set to TRUE, a backtrace will be displayed along with php errors. If
-| error_reporting is disabled, the backtrace will not display, regardless
-| of this setting
-|
-*/
-define('SHOW_DEBUG_BACKTRACE', TRUE);
+defined('FOPEN_READ')                           OR define('FOPEN_READ', 'rb');
+defined('FOPEN_READ_WRITE')                     OR define('FOPEN_READ_WRITE', 'r+b');
+defined('FOPEN_WRITE_CREATE_DESTRUCTIVE')       OR define('FOPEN_WRITE_CREATE_DESTRUCTIVE', 'wb'); // truncates existing file data, use with care
+defined('FOPEN_READ_WRITE_CREATE_DESCTRUCTIVE') OR define('FOPEN_READ_WRITE_CREATE_DESTRUCTIVE', 'w+b'); // truncates existing file data, use with care
+defined('FOPEN_WRITE_CREATE')                   OR define('FOPEN_WRITE_CREATE', 'ab');
+defined('FOPEN_READ_WRITE_CREATE')              OR define('FOPEN_READ_WRITE_CREATE', 'a+b');
+defined('FOPEN_WRITE_CREATE_STRICT')            OR define('FOPEN_WRITE_CREATE_STRICT', 'xb');
+defined('FOPEN_READ_WRITE_CREATE_STRICT')       OR define('FOPEN_READ_WRITE_CREATE_STRICT', 'x+b');
 
 /*
 |--------------------------------------------------------------------------
@@ -73,13 +73,13 @@ define('SHOW_DEBUG_BACKTRACE', TRUE);
 |       http://tldp.org/LDP/abs/html/exitcodes.html
 |
 */
-define('EXIT_SUCCESS', 0); // no errors
-define('EXIT_ERROR', 1); // generic error
-define('EXIT_CONFIG', 3); // configuration error
-define('EXIT_UNKNOWN_FILE', 4); // file not found
-define('EXIT_UNKNOWN_CLASS', 5); // unknown class
-define('EXIT_UNKNOWN_METHOD', 6); // unknown class member
-define('EXIT_USER_INPUT', 7); // invalid user input
-define('EXIT_DATABASE', 8); // database error
-define('EXIT__AUTO_MIN', 9); // lowest automatically-assigned error code
-define('EXIT__AUTO_MAX', 125); // highest automatically-assigned error code
+defined('EXIT_SUCCESS')        OR define('EXIT_SUCCESS', 0); // no errors
+defined('EXIT_ERROR')          OR define('EXIT_ERROR', 1); // generic error
+defined('EXIT_CONFIG')         OR define('EXIT_CONFIG', 3); // configuration error
+defined('EXIT_UNKNOWN_FILE')   OR define('EXIT_UNKNOWN_FILE', 4); // file not found
+defined('EXIT_UNKNOWN_CLASS')  OR define('EXIT_UNKNOWN_CLASS', 5); // unknown class
+defined('EXIT_UNKNOWN_METHOD') OR define('EXIT_UNKNOWN_METHOD', 6); // unknown class member
+defined('EXIT_USER_INPUT')     OR define('EXIT_USER_INPUT', 7); // invalid user input
+defined('EXIT_DATABASE')       OR define('EXIT_DATABASE', 8); // database error
+defined('EXIT__AUTO_MIN')      OR define('EXIT__AUTO_MIN', 9); // lowest automatically-assigned error code
+defined('EXIT__AUTO_MAX')      OR define('EXIT__AUTO_MAX', 125); // highest automatically-assigned error code
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 4988157e9..971a2341c 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -7,6 +7,10 @@ Version 3.0.2
 
 Release Date: Not Released
 
+-  General Changes
+
+   -  Updated the *application/config/constants.php* file to check if constants aren't already defined before doing that.
+
 Bug fixes for 3.0.2
 -------------------
 
diff --git a/user_guide_src/source/installation/upgrade_302.rst b/user_guide_src/source/installation/upgrade_302.rst
index 755e7788b..93d87ac41 100644
--- a/user_guide_src/source/installation/upgrade_302.rst
+++ b/user_guide_src/source/installation/upgrade_302.rst
@@ -12,3 +12,13 @@ Replace all files and directories in your *system/* directory.
 
 .. note:: If you have any custom developed files in these directories,
 	please make copies of them first.
+
+Step 2: Update your application/config/constants.php file
+=========================================================
+
+The *application/config/constants.php* file has been updated to check
+if constants aren't already defined before doing that, making it easier
+to add an environment-specific configuration.
+
+.. note:: If you've made modifications to this file, please make a
+	backup first and cross-check the differences first.
\ No newline at end of file