Conflicting component dependencies

This article talks about the issue where you get the "We found conflicting component dependencies" Composer error message while trying to setup or update Magento on-premise using the Web Setup Wizard.  

Affected products and versions

• Magento Commerce 2.2.x, 2.3.x
• Magento Open Source 2.2.x, 2.3.x

Issue

An error message similar to the following (actual package names and versions will vary): 

 We found conflicting component dependencies.
 You are trying to update package(s) magento/module-sample-data to 1.0.0-beta
 We've detected conflicts with the following packages:
 - magento/sample-data version 0.74.0-beta15. Please try to update it to one of the following package versions: 0.74.0-beta16, 0.74.0-beta14, 0.74.0-beta13, 0.74.0-beta12, 0.74.0-beta11, 0.74.0-beta10, 0.74.0-beta9, 0.74.0-beta8, 0.74.0-beta7

Cause

This message is displayed if Composer cannot determine which components to install or update.

Solution

To resolve component dependency issues, you should be a technical person who thoroughly understands how Composer works.

Typically, component dependency conflicts result from someone manually editing the Magento 2 composer.json file. It can also be caused by third-party modules that depend on earlier Magento components than the ones you have installed.

In the preceding example, the installed package magento/sample-data version 0.74.0-beta15 cannot be upgraded to 1.0.0-beta. However, 0.74.0-beta15 can be upgraded to 0.74.0-beta16 (or others).

Edit composer.json to make any of these changes and try the readiness check again.