MySQL Bugs: #119271: Connector/J fails to accept legacy value zeroDateTimeBehavior=convertToNull on multi-host URLs (failover), but works on

Bug #119271	Connector/J fails to accept legacy value zeroDateTimeBehavior=convertToNull on multi-host URLs (failover), but works on
Submitted:	30 Oct 11:14	Modified:	8 Dec 6:23
Reporter:	Wu Zhengyi (OCA)	Email Updates:
Status:	Verified	Impact on me:	None
Category:	Connector / J	Severity:	S3 (Non-critical)
Version:	All	OS:	Any
Assigned to:	Filipe Silva	CPU Architecture:	Any
Tags:	backward-compatibility, failover, multi-host, properties, zeroDateTimeBehavior

Description:
When using a multi-host JDBC URL (failover) with the legacy property value zeroDateTimeBehavior=convertToNull, the driver throws an exception stating the only acceptable values are CONVERT_TO_NULL, EXCEPTION, or ROUND. The same property/value works with a single-host URL.
Root cause:
Legacy value translation is applied only per-host in fixHostInfo() via replaceLegacyPropertyValues(hostProps).
In the failover path, FailoverConnectionProxy initializes properties from ConnectionUrl.getConnectionArgumentsAsProperties(), which returns the global properties map (this.properties) that has not been passed through replaceLegacyPropertyValues.
As a result, convertToNull is not normalized to CONVERT_TO_NULL and enum parsing fails in EnumPropertyDefinition.
Impact:
Backward-compatible URLs that rely on convertToNull fail in multi-host scenarios, but succeed in single-host scenarios, creating inconsistent behavior.
Exception (abridged):
com.mysql.cj.exceptions.CJException: The connection property 'zeroDateTimeBehavior' acceptable values are: 'CONVERT_TO_NULL', 'EXCEPTION' or 'ROUND'. The value 'convertToNull' is not acceptable.

How to repeat:
Use a JDBC URL with two hosts and legacy value:
jdbc:mysql://host1:3306,host2:3306?useSSL=false&zeroDateTimeBehavior=convertToNull
Attempt to connect (e.g., via DriverManager.getConnection).
Observe: connection fails with WrongArgumentException as above.
Control:
Using a single host URL with the same parameters succeeds:
jdbc:mysql://host1:3306?useSSL=false&zeroDateTimeBehavior=convertToNull

Suggested fix:
Normalize legacy property values in the global properties map, not only in per-host maps.
Concrete change:
In com.mysql.cj.conf.ConnectionUrl.collectProperties(...), after expanding and injecting properties, call:
fixProtocolDependencies(this.properties) [optional but consistent], and
replaceLegacyPropertyValues(this.properties)
so that getConnectionArgumentsAsProperties() returns already-normalized values used by FailoverConnectionProxy and other multi-host connection proxies.
Rationale:
Single-host paths use HostInfo built through fixHostInfo(), which already calls replaceLegacyPropertyValues(hostProps).
Multi-host paths use global properties; normalizing them ensures parity between single- and multi-host behaviors.
Compatibility:
Safe; only broadens acceptance of legacy values in global properties, maintaining existing behavior for per-host properties.

Thank you for your interest in MySQL Connector/J and for taking the time to file this report.

Verified as described.

https://github.com/mysql/mysql-connector-j/pull/119

Thank you for your contribution, but the issue is already being addressed internally.

Contribution submitted via Github - fix Bug #119271: Connector/J fails to accept legacy value zeroDateTimeBehavior=c 
(*) Contribution by Wu Zhengyi (Github wuzhengyi, mysql-connector-j/pull/119#issuecomment-3638095843): 
I confirm the code being submitted is offered under the terms of the OCA, and that I am authorized to contribute it.
---- Replied Message ----
| From | ***@***.***> |
| Date | 12/09/2025 22:54 |
| To | mysql/mysql-connector-j ***@***.***> |
| Cc | Zane ***@***.***>,
Author ***@***.***> |
| Subject | Re: [mysql/mysql-connector-j] fix Bug #119271: Connector/J fails to accept legacy value zeroDateTimeBehavior=convertToNull on multi-host URLs (failover), but works on (PR #119) |
mysql-oca-bot left a comment (mysql/mysql-connector-j#119)

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Contribution: git_patch_3074257288.txt (text/plain), 3.90 KiB.