Specify the platform configuration in composer.json

[morozov]

Q	A
Type	improvement
BC Break	no
Fixed issues	build #643647287

Having the target platform specified in Composer configuration will help make sure we won't lock the dependencies to a version incompatible with the oldest supported PHP version (see the linked build) without the need to use the oldest supported PHP in the development environment.

[greg0ire]

We should remove the composer.lock IMO, but until then, 👍

[morozov]

We should remove the composer.lock IMO

@greg0ire please see #3778. The practice shows that keeping it is the right choice.

How would removing it help to solve the problem of adding incompatible dependencies?

[greg0ire]

If we have no composer.lock, and somebody requires a version that requires PHP 7.3, the 7.2 build will fail and prevent the PR from being merged, won't it?

[morozov]

Instead of relying on CI building against the lowest supported version, this approach does the same in the development environment and does not require the lowest supported PHP version to resolve the dependencies.

[greg0ire]

What if the version in the composer.lock is not compatible with the highest supported PHP version? You would have the exact same issue, reversed.

Also see @beberlei and I struggling to fix the build the other day because of a similar issue: https://doctrine.slack.com/archives/GERFT2W5T/p1579212730062400?thread_ts=1579212399.059900&cid=GERFT2W5T

[morozov]

What if the version in the composer.lock is not compatible with the highest supported PHP version? You would have the exact same issue, reversed.

Then the incompatibility will be detected on CI. For most packages, the lowest version requirement is by design since they are using certain language features or APIs while the highest version requirement is implicit and is not by design. I.e. it's a relatively rare case to worry about.

[greg0ire]

Then the incompatibility will be detected on CI.

That's my point. There might be no incompatibility. There might exist a more recent version of the lib that is compatible with 7.4, yet one that is compatible with 7.2 and not 7.4 is in use.

while the lowest version requirement

did you mean "while the highest"?

[morozov]

did you mean "while the highest"?

Yes, corrected.

[morozov]

That's my point. There might be no incompatibility.

I see. Makes sense. Let’s reconsider this once it happens.

[greg0ire]

I agree that we will be quite unlucky if it happens. Relying on packages that aggressively bump the versions of php (such as ocramius/package-versions) increase the likelihood of this happening I think.