Composer - dependencies require a PHP version ">= 8.0.0". You are running 7.4.30."

Hi, Guys

Let's talk specifically about the Composer error in CodeIgniter ( 3 or 4 )

"Composer detected issues in your platform: Your Composer dependencies require a PHP version ">= 8.0.0". You are running 7.4.30."

In the backtrace we have:

\application\vendor\composer\platform_check.php

Here is the error trigger!

We need to block this trigger to resolve the issue

How do we tell Composer to block this trigger?

Easy!

composer install --ignore-platform-reqs

or

composer update --ignore-platform-reqs

But... what does this command do? Where does it record this?

Again, it's easy!
Two changes take place: 
1) platform_check.php is deleted by Composer. So the check file no longer exists
2) In the autoload_real.php file, the line below is deleted
require __DIR__ . '/platform_check.php';

You can do this manually by renaming the files (and comment line) to rename it in production environment. If you do Composer install or update, the file is created again. It's your free choice

I came to this conclusion by tracing the file through the IDE with each command in Composer

I think systems that use Composer behave in the same default way.

My suggest

https://webjump.com.br/en/composer-what-...nstall-it/

https://www.merixstudio.com/blog/what-co...t-project/

Another case...

If you have two PHP versions installed, for example 7.4 and 8, Composer will first look for the config inside the composer.json file. If not defined, it will detect the version installed on your machine.
At this point, problems can start if you develop in a version lower than PHP8. Errors such as
Message: syntax error, unexpected '|', expecting variable (T_VARIABLE)

Filename: ...application\vendor\psr\log\src\NullLogger.php

Line Number: 26
This error happens because CodeIgniter(3 or 4) is running in PHP7. On line 26 we have |\Stringable. This only PHP 8 reads.

How to troubleshoot the problem. Downgrade Composer packages to the version of PHP your machine is running.
In the link below you learn to see your version of PHP
https://phoenixnap.com/kb/check-php-version

How to downgrade, or update, to the desired version?
In the Application folder of CodeIgniter (App CI 4) we have the file
composer.json
Add the following lines
"config": {
"platform": {
"php": "7.4.30"
}
But be careful with the syntax, there is a comma separating it
Example
{
"config": {
"platform": {
"php": "7.4.30"
}
},
"require": {
"phpoffice/phpspreadsheet": "^1.6",
"mpdf/mpdf": "^8.0"
}
}
Save the modified file
Finally, run composer update
When going to the production environment, make the necessary adjustments


Be happy and code the easiest and most efficient way