not able to install a package with composer

Question

Hello and Thanks in advance. I am trying to install a package with composer but at first it gave me an error about requiring ext-dom and ext-mbstring extensions, I solved that but now it's giving me this error:

Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Conclusion: don't install illuminate/html v5.0.0
    - Conclusion: remove laravel/framework v6.9.0
    - Installation request for illuminate/html ^5.0 -> satisfiable by illuminate/html[5.0.x-dev, v5.0.0].
    - Conclusion: don't install laravel/framework v6.9.0
    - illuminate/html 5.0.x-dev requires illuminate/support ~5.0 -> satisfiable by illuminate/support[5.0.x-dev, 5.1.x-dev, 5.2.x-dev, 5.3.x-dev, 5.4.x-dev, 5.5.x-dev, 5.6.x-dev, 5.7.17, 5.7.18, 5.7.19, 5.7.x-dev, 5.8.x-dev, v5.0.0, v5.0.22, v5.0.25, v5.0.26, v5.0.28, v5.0.33, v5.0.4, v5.1.1, v5.1.13, v5.1.16, v5.1.2, v5.1.20, v5.1.22, v5.1.25, v5.1.28, v5.1.30, v5.1.31, v5.1.41, v5.1.6, v5.1.8, v5.2.0, v5.2.19, v5.2.21, v5.2.24, v5.2.25, v5.2.26, v5.2.27, v5.2.28, v5.2.31, v5.2.32, v5.2.37, v5.2.43, v5.2.45, v5.2.6, v5.2.7, v5.3.0, v5.3.16, v5.3.23, v5.3.4, v5.4.0, v5.4.13, v5.4.17, v5.4.19, v5.4.27, v5.4.36, v5.4.9, v5.5.0, v5.5.16, v5.5.17, v5.5.2, v5.5.28, v5.5.33, v5.5.34, v5.5.35, v5.5.36, v5.5.37, v5.5.39, v5.5.40, v5.5.41, v5.5.43, v5.5.44, v5.6.0, v5.6.1, v5.6.10, v5.6.11, v5.6.12, v5.6.13, v5.6.14, v5.6.15, v5.6.16, v5.6.17, v5.6.19, v5.6.2, v5.6.20, v5.6.21, v5.6.22, v5.6.23, v5.6.24, v5.6.25, v5.6.26, v5.6.27, v5.6.28, v5.6.29, v5.6.3, v5.6.30, v5.6.31, v5.6.32, v5.6.33, v5.6.34, v5.6.35, v5.6.36, v5.6.37, v5.6.38, v5.6.39, v5.6.4, v5.6.5, v5.6.6, v5.6.7, v5.6.8, v5.6.9, v5.7.0, v5.7.1, v5.7.10, v5.7.11, v5.7.15, v5.7.2, v5.7.20, v5.7.21, v5.7.22, v5.7.23, v5.7.26, v5.7.27, v5.7.28, v5.7.3, v5.7.4, v5.7.5, v5.7.6, v5.7.7, v5.7.8, v5.7.9, v5.8.0, v5.8.11, v5.8.12, v5.8.14, v5.8.15, v5.8.17, v5.8.18, v5.8.19, v5.8.2, v5.8.20, v5.8.22, v5.8.24, v5.8.27, v5.8.28, v5.8.29, v5.8.3, v5.8.30, v5.8.31, v5.8.32, v5.8.33, v5.8.34, v5.8.35, v5.8.36, v5.8.4, v5.8.8, v5.8.9].
    - don't install illuminate/support 5.5.x-dev|don't install laravel/framework v6.9.0
    - don't install illuminate/support v5.5.0|don't install laravel/framework v6.9.0
    - don't install illuminate/support v5.5.16|don't install laravel/framework v6.9.0
    - don't install illuminate/support v5.5.17|don't install laravel/framework v6.9.0
    - don't install illuminate/support v5.5.2|don't install laravel/framework v6.9.0
    - don't install illuminate/support v5.5.28|don't install laravel/framework v6.9.0
    - don't install illuminate/support v5.5.33|don't install laravel/framework v6.9.0
    - don't install illuminate/support v5.5.34|don't install laravel/framework v6.9.0
    - Installation request for laravel/framework (locked at v6.9.0, required as ^6.2) -> satisfiable by laravel/framework[v6.9.0].

Answer 1

After further searching I found out that This package is no longer supported by laravel v6 and in packagist I found this:

This package is abandoned and no longer maintained. The author suggests using the laravelcollective/html package instead.

Answer 2

Link Your software dependencies have an incompatible version conflict.

At the same time you want to install any Laravel 4.2.x version, and "zizaco/entrust" from its master branch. And that master branch requires at least Laravel 5.0 (roughly speaking).

The problem comes from the dependency on branches. It's likely that the package zizaco/entrust once was using Laravel 4.2 in its master branch, and that you were able to install your dependencies at that day. But the very moment this branch gets updated with an incompatible version requirement, you will never ever be able to run composer update and get updated dependencies.

Always use tagged versions! Ideally you use a relaxed version requirement that allows for compatible updates. This should be expressed as a tilde-two-number version requirement: ~1.2 would install a version 1.2.0 and up (like 1.2.99 or 1.2.100), and also 1.3 and up. If you need a certain patch release: Caret-three-number version ^1.2.10 will install 1.2.10 or up, also 1.3 and up.

Using this version requirement instead of dev-master will allow you to use released versions instead of the unstable state in the master branch, and allows you to address the most recent version that still works with Laravel 4.2. I guess that would be zizaco/entrust version 1.3.0, but version 1.2 would also qualify. Go with "zizaco/entrust": "~1.2".