Valid $or Pattern fails RuleCompiler check

[InfamousBreeze]

Describe the bug

When using the RuleCompiler::check function to validate a rule pattern, I am receiving the following issue despite the pattern being valid:

Input:

{
    "$or": [{
        "title": [{
            "anything-but": ["Test"]
        }]
    }, {
        "severity": [{
            "numeric": ["=", 5]
        }]
    }]
}

Error message:

Unrecognized match type title at [Source: (String)"{ "$or": [{ "title": [{ "anything-but": ["Test"] }] }, { "severity": [{ "numeric": ["=", 5] }] }] }"; line: 3, column: 19]

Here "title" and "severity" are property keys of our JSON document and not reserved keywords but it seems to be hitting the validation logic at https://github.com/aws/event-ruler/blob/v1.8.1/src/main/software/amazon/event/ruler/RuleCompiler.java#L422 and failing.

To Reproduce

Invoke the check() function with the above payload

Expected behavior

check() function should return null as pattern is valid

Environment:

Java Version: JDK21
Ruler Package: 1.8.1

Additional context

We are internal SDO team

[Ben-Rigby]

From the code in the GenericMachine class, it looks like JSONRuleCompiler is the preferred RuleCompiler, which is supported by the wording in its [doc string]:

Represents an updated compiler comparing to RuleCompiler class

From testing, using JSONRuleCompiler in place of RuleCompiler when validating the input in this issue, it returns in a successful response.

{
    "$or": [{
        "title": [{
            "anything-but": ["Test"]
        }]
    }, {
        "severity": [{
            "numeric": ["=", 5]
        }]
    }]
}

The README.md suggests to use RuleCompiler for checking if rules are valid.

Question for package maintainers: Does this documentation need to be updated? Or is there a reason to use RulerCompiler over JSONRuleCompiler.