fixes #1246 Coercion bug

[stevehu]

No description provided.

[Copilot]

Pull request overview

This PR addresses issue #1246 by preventing schema ID/anchor parsing from coercing non-string JSON nodes into text, which could incorrectly influence schema resource registration and $ref resolution (notably for Draft 4 where the ID keyword is id).

Changes:

• Added a regression test covering Draft 4 schema resolution involving a $ref into the Draft 4 meta-schema.
• Updated Dialect.readText(...) to return a value only when the target field exists and is a JSON string (no coercion).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/test/java/com/networknt/schema/Issue1246Test.java	Adds regression coverage to ensure Draft 4 $ref resolution is not impacted by non-text nodes encountered under id-named fields.
src/main/java/com/networknt/schema/dialect/Dialect.java	Tightens ID/anchor reading to ignore non-string values, avoiding unintended coercion effects.

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[justin-tay]

Since the issue is that it shouldn't be coercing then these changes are confusing as asString() does coercing but isString() ensures it's a StringNode so the intent isn't clear.

More appropriate to use the following instead

    private static String readText(JsonNode node, String field) {
        JsonNode fieldNode = node.get(field);
        return fieldNode == null ? null : fieldNode.stringValue(null);
    }

[stevehu]

Makes sense. I have made the code change based on your recommendation. Thanks a lot.