@Pattern error message "{0}" is not resolved. [SPR-17217]

yoshikawaa opened SPR-17217 and commented

Application

Spring Boot Web MVC Application
Spring Boot 2.0.4.RELEASE
Sample : https://github.com/yoshikawaa/spring-boot-pattern-demo

Problem

There are cases where @Pattern error message {0} is not resolved.

• ValidationMessages.properties

javax.validation.constraints.Pattern.message = {0} must match "{regexp}".

• application.properties

spring.messages.basename = ValidationMessages

• Form

public class DemoForm {
    @Pattern(regexp = "\\d{3}")    // -> message [ valid must match "\d{3}".  ]
    private String valid;
    @Pattern(regexp = "\\d{1,3}") // -> message [ {0} must match "\d{1,3}".  ]
    private String invalid;
    // omit getter and setter
}

My validation is that if a range of digits is used in a regular expression, the mechanism for resolving {0} does not work properly.

Controller
    @PostMapping
    public String post(@Valid DemoForm form, BindingResult result) {
        result.getFieldErrors().forEach(e -> logger.info("field:{},error:{}", e.getField(), e.getDefaultMessage()));
        // log [ field:valid,error:{0} must match "\d{3}". ]
        // log [ field:invalid,error:{0} must match "\d{1,3}". ]
        return "demo";
    }

When logging BindingResult with Controller, you can see that LocalValidatorFactoryBean (Hibernate Validator) resolves message variable {regexp} beforehand.
After that, when Spring MVC resolve the message, it is considered that the regular expression in the message is obstructing resolution of {0}.

Affects: 5.0.8

Reference URL: https://github.com/spring-projects/spring-boot/issues/14163

Reproduce the issue with ValidationMessages.properties, application.properties, DemoForm, and the Controller example, then trace how LocalValidatorFactoryBean and Spring MVC resolve the BindingResult field error. Compare the messages with and without the ranged regular expression, and consider the issue done when the {0} variable resolves consistently without breaking {regexp} substitution.