I write “composer require larabook/gateway” for install the package but I get this error

Question

I am trying to require the larabook/gateway composer package by running composer require larabook/gateway. I'm using Laravel 5.8, php 7 and version ^3.3 for larabook/gateway. This however yields the following error:

./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages

Problem 1
- Conclusion: don't install larabook/gateway 3.3.4
- Conclusion: don't install larabook/gateway 3.3.3
- Conclusion: don't install larabook/gateway 3.3.2
- Conclusion: don't install larabook/gateway 3.3.1
- Conclusion: remove nesbot/carbon 2.16.3
- Installation request for larabook/gateway ^3.3 -> satisfiable by larabook/gateway[3.3, 3.3.1, 3.3.2, 3.3.3, 3.3.4].
- Conclusion: don't install nesbot/carbon 2.16.3
- larabook/gateway 3.3 requires nesbot/carbon ~1.20 -> satisfiable by nesbot/carbon[1.20.0, 1.21.0, 1.22.0, 1.22.1, 1.23.0, 1.24.0, 1.24.1, 1.24.2, 1.25.0, 1.26.0, 1.26.1, 1.26.2, 1. 26.3, 1.26.4, 1.27.0, 1.28.0, 1.29.0, 1.29.1, 1.29.2, 1.30.0, 1.31.0, 1.31.1, 1.32.0, 1.33.0, 1.34.0, 1.34.1, 1.34.2, 1.34.3, 1.34.4, 1.35.0, 1.35.1, 1.36.0, 1.36.1, 1.36.2].
- Can only install one of: nesbot/carbon[1.26.3, 2.16.3].

- Installation request for nesbot/carbon (locked at 2.16.3) -> satisfiable by nesbot/carbon[2.16.3].

Installation failed, reverting ./composer.json to its original content.

Could you please help me find out what causes this error and how to prevent it.

Answer 1

You (probably) have an entry in your composer file for nesbot/carbon which resolved to version 2.16.3 while larabook/gateway required the same package at version ~1.20, the version your composer is locked to does not satisfy this requirement. To solve this you will need to either remove your direct version of nesbot/carbon (please note that this might break some code of yours) or check with the maintainers of larabook/gateway if they can support the 2.16.3 version of the carbon package.