PostgreSQLSchemaManager does not resolve single-quote quoting when retrieving schema information

[sbuerk]

Bug Report

Q	A
Version	3.8.3, 4.0.1

Summary

PostgreSQL uses a single-quote to quote a single-quote,
ending in double single-quotes ''. This is not reversed
correctly when retrieving the schema information, ending
in having a php string value with double single-quotes in it.

For example, if a default json vale {"key": "value with a single quote ' in string value"}
should be used as field default value.

Current behaviour

Retrieving the schema information, the column default retrieved with
Column->getDefault() returns:

{"key": "value with a single quote '' in string value"}

instead of

{"key": "value with a single quote ' in string value"}

How to reproduce

Adding this test to tests/Functional/Schema/PostgreSQLSchemaManagerTest.php

    public function testJsonDefaultValue(): void
    {
        $testTable = new Table('test_json');
        $testTable
            ->addColumn('foo', Types::JSON)
            ->setDefault('{"key": "value with a single quote \' in string value"}');
        $this->dropAndCreateTable($testTable);

        $columns = $this->schemaManager->listTableColumns('test_json');

        self::assertSame(Types::JSON, $columns['foo']->getType()->getName());
        self::assertSame(
          '{"key": "value with a single quote \' in string value"}',
          $columns['foo']->getDefault()
        );
    }

demonstrates how this can be reproduced, ending up in a error with following missmatch:

-'{"key": "value with a single quote ' in string value"}'
+'{"key": "value with a single quote '' in string value"}'

A corresponding native SQL would be:

CREATE TABLE test_json (
  foo JSON DEFAULT '{"key": "value with a single quote '' in string value"}'
);

Expected behaviour

Column->getDefault() should return

{"key": "value with a single quote ' in string value"}