Cron doesn't run all PHP functions from shell - php

Question

To run a PHP function from a file:
php -r 'require "/var/www/html/functions.php"; function1();'
To add that to Cron:
crontab -e
The full statement would be:
*/1 * * * * php -r 'require "/var/www/html/functions.php"; function1();'
This would run the function every minute for the sake of testing.
This works fine for a simple function, that for example, writes to a file for the sake of testing.
But I have another complicated function2 that calls other functions and performs other file reads.
Changing Cron to:
*/1 * * * * php -r 'require "/var/www/html/functions.php"; function2();'
This fails to run. There are no errors in the code, it runs perfectly when executed in shell.
It also fails to run inside a shell script called by Cron.
It fails to run with full binary path, although it doesn't matter cause previous one worked:
*/1 * * * * /usr/bin/php -r 'require "/var/www/html/functions.php"; function2();'
It also fails to run using:
crontab -u www-data -e
In case someone mentions it.
============================EDIT 01:============================
Out of desperation, I was willing to at least try the suggestion by James
I created a cron.php file launched it in the browser, it works.
Now through cron & php:
*/1 * * * * php -q /var/www/html/cron.php
It doesn't work.
Through cron & curl:
curl http://ip/cron.php
It works. But this isn't optimal.

Answer 1

Running PHP scripts from cron jobs
A common method for running PHP scripts from a cron job is to use a command-line program such as curl or wget. For example, the cron job runs a command similar to the following command:
curl http://example.com/script.php
In this command, curl retrieves the web page, which then runs the PHP script.
However, there is a better way to run PHP scripts on your web site from cron jobs. You can run the script directly by using the PHP command-line interpreter. This method is just as effective, and usually faster. The following command shows how to run a script using the PHP command-line interpreter:
php -q /home/username/public_html/script.php
In this example, the PHP command-line interpreter runs the script.php file. The -q option enables quiet mode, which prevents HTTP headers from being displayed.
Depending on the code in your PHP script, it may only run correctly when called from a specific directory. For example, if the script uses relative paths to include files, it will only run if it is called from the correct directory. The following command shows how to call a PHP script from a specific directory:
cd /home/username/public_html/; php -q script.php