Invalid composer version constraint ^2.1

[rfay]

Describe the bug

The current constraint here is invalid, composer has never supported a 2.1 branch (there is a 2.2). I'm not sure how this can work, but it seems that platform may try and fail to use 2.1, so just uses 2.8.x currently instead.

Include some logs

None needed

Reproducing

Look at it. Do a composer self-update -h

Expected behavior

Use a valid version

Your environment

Platform

Screenshots

No response

Additional context

No response

[gilzow]

Per the composer docs, the ^ constraint evaluates to >=2.1 <3.0.0 which is valid.

[rfay]

Platform docs say ^2 as a default, https://docs.platform.sh/languages/php.html#dependencies

[gilzow]

Composer has definitely had a 2.1 version: https://github.com/composer/composer/releases/tag/2.1.0

The docs are just a reference and not a specific as a project may need a specific version (or specific range).

Additionally, projects do not need to define composer as a global dependency for the project and can instead require a specific version defined in their composer.json(.lock).

That said, Composer 2.1 is EoL so we should go ahead and update to the LTS 2.2 (ie ^2.2) at a minimum in the template. Or, since Drupal requires Composer to be at or greater than v2.3.6, update the template to use ^2.3.6.

[rfay]

I concede all of your points. This is a valid spec. Apparently Platform installs composer using a composer require rather than the perhaps more common techniques. It means that this spec in the platform or upsun config is a little odd, but fine.

However, there's no reason for this ^2.1 spec, it's meaningless in the last couple of years. ^2 is obvious and raises no eyebrows, and does no harm, and matches the platform and upsun docs. ^2 does fine for all Drupal versions.