Make AbstractSchemaManager covariant to its template argument

[zerkms]

Q	A
Type	bug
Fixed issues

Summary

<?php
declare(strict_types=1);

abstract class AbstractPlatform {}

class PostgreSQLPlatform extends AbstractPlatform {}

/**
 * @template T of AbstractPlatform
 */
abstract class AbstractSchemaManager {}

/**
 * @extends AbstractSchemaManager<PostgreSQLPlatform>
 */
class PostgreSQLSchemaManager extends AbstractSchemaManager {}

function createSchemaManager(): AbstractSchemaManager
{
    return new PostgreSQLSchemaManager();
}

$schemaManager = createSchemaManager();

if (!$schemaManager instanceof PostgreSQLSchemaManager) {}

ERROR: [RedundantCondition](https://psalm.dev/122) - 25:6 - AbstractSchemaManager<AbstractPlatform> cannot be identical to PostgreSQLSchemaManager

vs

<?php
declare(strict_types=1);

abstract class AbstractPlatform {}

class PostgreSQLPlatform extends AbstractPlatform {}

/**
 * @template-covariant T of AbstractPlatform
 */
abstract class AbstractSchemaManager {}

/**
 * @extends AbstractSchemaManager<PostgreSQLPlatform>
 */
class PostgreSQLSchemaManager extends AbstractSchemaManager {}

function createSchemaManager(): AbstractSchemaManager
{
    return new PostgreSQLSchemaManager();
}

$schemaManager = createSchemaManager();

if (!$schemaManager instanceof PostgreSQLSchemaManager) {}

No issues!

[github-actions]

There hasn't been any activity on this pull request in the past 90 days, so it has been marked as stale and it will be closed automatically if no further activity occurs in the next 7 days.
If you want to continue working on it, please leave a comment.

[zerkms]

🤷

[greg0ire]

Can you please add something inside the static-analysis directory reproducing the issue described in your original message?

[zerkms]

I'm about to leave to a vacation so will append those whenever I return :-)

[greg0ire]

Enjoy your vacation!

[zerkms]

Finally I'm here and provided the requested statical analysis test :-)

Without the suggested improvement the test fails with

ERROR: RedundantCondition - static-analysis/a.php:21:6 - Doctrine\DBAL\Schema\AbstractSchemaManager<Doctrine\DBAL\Platforms\AbstractPlatform> cannot be identical to Doctrine\DBAL\Schema\PostgreSQLSchemaManager (see https://psalm.dev/122)
if (!$schemaManager instanceof PostgreSQLSchemaManager) {

[greg0ire]

Does this apply only to dbal 4?

[zerkms]

@greg0ire it applies to every implementation that defines it as @template T of AbstractPlatform.

I see that all 3.x and 5.x do that too.

[greg0ire]

We use a merge up workflow, please retarget the pr to 3.x

The base branch was changed.

[zerkms]

Done

[greg0ire]

Thanks @zerkms