Suggested improvement to the installation instructions (install.md)

[rwanwork]

Bug report

When installing CDash on a "new" system and using the bash ./install.sh command, I encountered the following error:

PHP Warning:  require(.../CDash/vendor/autoload.php): Failed to open stream: No such file or directory in  .../CDash/artisan on line 18

It wasn't clear to me in the instructions what was causing this problem. As someone who doesn't use php, the solution wasn't obvious (perhaps it was obvious to others?).

Expected Behavior

I expected the installation of CDash to work.

Actual Behavior

The above error message was displayed and installation stopped. The error message was also misleading because I thought I am missing a vendor/autoload.php file in my cloned repository.

CDash Version

I was installing the latest version of CDash from the GitHub repository.

Additional Information

This was on Ubuntu 25.04, without the use of Docker.

After a search for the error message, I came across this page (https://stackoverflow.com/questions/41209349/requirevendor-autoload-php-failed-to-open-stream) which explained I had to initialise composer. Moreover, I also had to have the ext-xdebug module installed (which isn't listed in install.md) or else I get this error:

Problem 1
  - Root composer.json requires PHP extension ext-xdebug * but it is missing from your system. Install or enable PHP's xdebug extension.

Of course, this was a requirement of composer and not CDash. Anyway, after running composer install, the installation of CDash using install.sh was able to proceed.

I know this isn't a problem of CDash, but the error message implies it is (that the vendor/ directory is missing). So maybe explicitly mentioning this in install.md might help?