Personal Catalogue: PHP & MySQL — Chapter 9, Exercise 3
====================================================

TASK
Set display_errors = Off and log_errors = On in a local PHP test
setup, deliberately trigger a real PHP error (e.g. calling an
undefined function), and confirm the error is genuinely absent from
the browser output while still appearing in the configured log file.

SOLUTION

1. Locate the local php.ini in use (php --ini shows the loaded file
   path), or scope the settings to a single test file/directory via a
   .htaccess (if using Apache with mod_php):

    php_flag display_errors Off
    php_flag log_errors On
    php_value error_log /tmp/php_test_errors.log

   Or directly in php.ini:

    display_errors = Off
    log_errors = On
    error_log = /tmp/php_test_errors.log

2. Restart the web server (or PHP-FPM) so the new settings take
   effect.

3. Create a small test file:

    <?php
    this_function_does_not_exist();

4. Visit the test file in a browser.

Expected result: the page loads completely blank (or shows only
whatever HTML came before the error, if any) — no "Fatal error:
Uncaught Error: Call to undefined function..." text visible anywhere
in the response, confirmed by viewing the page's own source (View
Source), not just the rendered page, since some errors can be present
but invisible due to CSS.

5. Check the log file:

    cat /tmp/php_test_errors.log

Expected output: a real, timestamped log entry along the lines of:

    [DATE TIME UTC] PHP Fatal error:  Uncaught Error: Call to undefined
    function this_function_does_not_exist() in /path/to/test.php:2

The full error detail — file path, line number, error type — is
present in the log, even though none of it reached the browser.

WHY THIS WORKS AS AN ANSWER
----------------------------
It verifies both halves of the setting's real purpose directly —
confirming the error is truly invisible in the browser response (not
just visually hidden) via View Source, and confirming the same error
detail is still fully captured in the log file — rather than only
checking one side of the behavior.