@sentient0being Thank you for making this PR. I have a few questions from a very quick read of it.

1. It seems that this PR adds a predicate to read a string array value, but it isn't actually used anywhere. Is that what you intended?
2. Ideally there would be a tests where this improvement is observable.
3. Should we deprecate the existing getValue() predicate, as it sounds like it will never be useful?

@owen-mc Thank you for your review. This PR indeed adds a predicate for reading string array values, but it is not yet used in the code. My intention was to provide this functionality for the SpringRequestMappingMethod class to properly handle URL arrays in the Spring framework.

package org.springframework.web.bind.annotation.test;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping(value = "/test")
public class SpringControllerTest {
    
    @RequestMapping(value = "/single")
    public String singleStringValue(@RequestParam(value = "username") String username) {
        return username;
    }
}

import java
import semmle.code.java.frameworks.spring.SpringController


string getUrlOrDefault(SpringRequestMappingMethod m) {
    result = m.getDeclaringType().getAnAnnotation().getAStringArrayValue("value") + m.getArrayValue()
}

from SpringRequestMappingMethod m
where
    exists(SpringRequestMappingParameter p | p = m.getARequestParameter() and p.isTaintedInput())
select m, "Request mapping method",getUrlOrDefault(m), "URL value"

Thanks again for this change - I've checked and it's all correct. I've added tests and a change note, changed the predicate name slightly and deprecated the original predicate (which doesn't work). I couldn't easily add all these changes to this PR so I've made a new PR #19556.