polyfill-ctype | component provides a partial , native PHP implementation | Web Framework library

The problem is that you require doctrine/common in v2. This depends on doctrine/persistence in v1. Updating all your packages to Symfony 5.2 will also update symfony/doctrine-bridge to 5.2 - and this requires doctrine/persistence in v2.

Updating doctrine/common to v3 in your composer.json could help to resolve the problem. Also, since you are using symfony/flex already, you can remove all explicit version constraints on the Symfony packages - it's sufficient to define the Symfony version further down in the extra section as you already did. This makes it way easier to update all Symfony packages, as you only need to change this one line

That composer.json file is a bit of a mess. Some Symfony packages on 5.3, some even on 5.1, and many on 6.

Also you are controlling Symfony versioning from extra.symfony.require, and at the same time from the discrete version constraints. You include some packages that no longer exist on 6.0 (symfony/security-guard), and are missing some that should be installed on a 6.0 version.

It's simply not on an installable state.

I've managed to make it installable changing it like this:

I have had this error when using symfony server:start with docker inside a php-alpine container. Each time i run migrations or doctrine:schema:update in a fresh installed instance, my symfony local web-server would throw error: issue with server callback error="unable to fetch the response from the backend: malformed MIME header: missing colon: "FROM information_schema.schemata I solved it by dropping the alpine container and building everything from the FROM ubuntu:20.04 image: i had to install php, drivers and all dependencies too. This did not go well with my production env because the image was above 1GB, meaning it had binaries i did not need in production. From experience the symfony local web-server needs a python environment but am not sure on that.

After some days, i stumbled on this git repository: https://github.com/dunglas/symfony-docker. which is recommended from Symfony docs here: Using Docker with Symfony. It uses caddy as the web-server. I learnt from it, tweaked to suit my needs and from then never used symfony local web-server. Its a good project, kudos to Kévin Dunglas and maintainers. The php image is about 200MB. Caddy too is about 40MB. Great for both prod and dev environments.

Please peruse the repo and adopt what you can or everything.

Disclaimer: This is not an answer to your problem/error, but an easy alternative.

You can just require an explicit version of a package without any additional constraints, and that will version-lock other dependencies.

Either manually add "symfony/polyfill-ctype": "1.17" to your composer.json file, or use composer require symfony/polyfill-ctype:1.17 from the command line.

I will warn you that this might cause you headaches in the future when you upgrade, so make sure that you document it somewhere. Specifically, you or someone else in the future will look at the code and say "we aren't even using that", and then remove it.

Please have a look at the documentation of Composer scripts. It explains pretty obvious:

post-install-cmd: occurs after the install command has been executed with a lock file present.

If you are using composer install with a lock file not present (as indicated from the console output), this event is not fired.

Add the following to the require section of your composer.json file:

Try changing composer.json

From:

The solution is to execute:

You have conflicting requirements.

On extra.symfony.require you say you want 5.3.*.

But on your individual Symfony requirements you are specifying either ^5.2 or 5.2.* (and in some cases ^5.3 as well).

When a project uses Symfony Flex (as is your case), the presence of extra.symfony.require will be used to restrict what package versions to install for many/most Symfony packages. But only if you do not declare a specific version on your require section.

In this case, you are already specifying a version on the 5.* range on extra.symfony.require. Leave that one like that, and just use * as a version constraint for all the other Symfony Packages in the require section.

(Note that's it's not really all, since some packages are not managed by Flex, just update the ones that have versions declares in the 5.* range)