Magento 2 don't support IPv6 for DB connection

[chrom]

Information on your environment:
Magento 2.2.5

Steps to reproduce:
set configuration for DB connection in IPv6 format (unconditionally at this address you should have an appropriate service)

• Expected results:
  connection to DB
• Actual results:
  Error:
  Exception #0 (Zend_Db_Adapter_Exception): SQLSTATE[HY000] [2002] Failed to parse IPv6 address "[:3306" Exception #1 (PDOException): SQLSTATE[HY000] [2002] Failed to parse IPv6 address "[:3306"

[magento-engcom-team]

Hi @chrom. Thank you for your report.
To help us process this issue please make sure that you provided the following information:

• Summary of the issue
• Information on your environment
• Steps to reproduce
• Expected and actual results

Please make sure that the issue is reproducible on the vanilla Magento instance following Steps to reproduce. To deploy vanilla Magento instance on our environment, please, add a comment to the issue:

@magento-engcom-team give me {$VERSION} instance

where {$VERSION} is version tags (starting from 2.2.0+) or develop branches (2.2-develop +).
For more details, please, review the Magento Contributor Assistant documentation.

@chrom do you confirm that you was able to reproduce the issue on vanilla Magento instance following steps to reproduce?

• yes
• no

[engcom-backlog-nickolas]

Hello @chrom, thank you for your report. GitHub is intended for bug reports, please use https://github.com/magento/community-features for other suggestions like improvements or feature requests.

[chrom]

@engcom-backlog-nickolas Is it impossible to connect the database is not it a bug?

[engcom-backlog-nickolas]

@chrom, this is duplicate of #774, and already has corresponding ticket MAGETWO-31246. It will be processed faster if you move this to https://github.com/magento/community-features

Best regards!