Inconsistent escaping during database migration with MySQL

[LouisdeLooze]

Preconditions and environment

• Clean Magento 2.4.7-p3
• Reproducible on MySQL 8, cannot be reproduced on MariaDB 10.6

Steps to reproduce

1. Make custom module with a declarative schema that contains a PHP class as default. For example:

<?xml version="1.0"?>
<schema xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Setup/Declaration/Schema/etc/schema.xsd">
    <table name="test_module_db" resource="default" engine="innodb">
        <column xsi:type="varchar" name="model" nullable="true" default="Test\\Module\\Model\\Default" comment="Corresponding Model"/>
    </table>
</schema>

2. Run setup:upgrade
3. Run setup:db:status

Expected result

No database migrations needed, just ran the migrations.

Actual result

Migration is needed (breaking zero-downtime deployments for no reason), this is the difference:
from xml:

array(5) {
  ["type"]=>
  string(7) "varchar"
  ["nullable"]=>
  bool(true)
  ["default"]=>
  string(28) "Test\\Module\\Model\\Default"
  ["length"]=>
  int(255)
  ["comment"]=>
  string(19) "Corresponding Model"
}

from MySQL:

array(5) {
  ["type"]=>
  string(7) "varchar"
  ["nullable"]=>
  bool(true)
  ["default"]=>
  string(25) "Test\Module\Model\Default"
  ["length"]=>
  int(255)
  ["comment"]=>
  string(19) "Corresponding Model"
}

for reference, MariaDB:

array(5) {
  ["type"]=>
  string(7) "varchar"
  ["nullable"]=>
  bool(true)
  ["default"]=>
  string(25) "Test\\Module\\Model\\Default"
  ["length"]=>
  int(255)
  ["comment"]=>
  string(19) "Corresponding Model"
}

Additional information

No response

Release note

No response

Triage and priority

• Severity: S0 - Affects critical data or functionality and leaves users without workaround.
• Severity: S1 - Affects critical data or functionality and forces users to employ a workaround.
• Severity: S2 - Affects non-critical data or functionality and forces users to employ a workaround.
• Severity: S3 - Affects non-critical data or functionality and does not force users to employ a workaround.
• Severity: S4 - Affects aesthetics, professional look and feel, “quality” or “usability”.

[m2-assistant]

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[m2-assistant]

Hi @engcom-Hotel. Thank you for working on this issue.
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[engcom-Hotel]

Hello @LouisdeLooze,

Thanks for the report and collaboration!

But we are unable to get the expected and actual result, request you to please elaborate on those.

Thanks

[LouisdeLooze]

Hi @engcom-Hotel

Directly after running setup:upgrade, running setup:db:status will output (does not matter how many times DB upgrade command is ran):

Declarative Schema is not up to date
Run 'setup:upgrade' to update your DB schema and data.

The extra output from above is when debugging \Magento\Framework\Setup\Declaration\Schema\Comparator::compare.
I added the following before the return to show the differences between the sensitive parameters:

if (! (get_class($first) === get_class($second) &&
       $first->getDiffSensitiveParams() === $second->getDiffSensitiveParams())) {
       var_dump($first->getDiffSensitiveParams());
       var_dump($second->getDiffSensitiveParams());
}

And that shows the difference in escaping the backslashes, which makes the comparator think they are different. Resulting in a permanent state of the declarative schema being not up to date.

[engcom-Hotel]

Hello @LouisdeLooze,

Thanks for the report and collaboration!

We have tried to reproduce the issue in the latest 2.4-develop branch and the issue has been reproducible for us. Please refer to the screenshot below for reference:

The below module has been created by us to reproduce the issue:
Issue39491.zip

Hence confirming the issue.

Thanks