Fix NullPointerException resolving type hints for JSON with duplicate properties

[ctomc]

Problem

GenericJacksonJsonRedisSerializer (Jackson 3, default typing enabled) throws a NullPointerException when deserializing any value whose JSON contains a duplicate property name.

TypeResolver.readTree(byte[]) builds the JSON node tree with a DeserializationContext obtained from ObjectMapper._deserializationContext(), which is never bound to the parser. Its stream-read capabilities therefore stay null, and the first time BaseNodeDeserializer._handleDuplicateProperty consults StreamReadCapability.DUPLICATE_PROPERTIES it fails:

java.lang.NullPointerException: Cannot invoke
"tools.jackson.core.util.JacksonFeatureSet.isEnabled(...)" because "this._readCapabilities" is null
    at tools.jackson.databind.DeserializationContext.isEnabled(DeserializationContext.java:470)
    at tools.jackson.databind.deser.jackson.BaseNodeDeserializer._handleDuplicateProperty(BaseNodeDeserializer.java:148)
    at ...GenericJacksonJsonRedisSerializer$TypeResolver.readTree(GenericJacksonJsonRedisSerializer.java:509)

Duplicate property names are valid JSON (RFC 8259) and occur in practice — for example in cache entries written by the Jackson 2 serializer, or by a polymorphic type whose @JsonTypeInfo(include = As.PROPERTY) type-id name coincides with a bean property of the same name (Jackson 2 emitted both as duplicate keys). Such entries can no longer be read back under the Jackson 3 serializer — not even to be evicted.

Reported in #3396, with a minimal reproduction there.

Fix

Bind the parser to the context before deserializing, so its stream-read capabilities are initialized. This mirrors how ObjectMapper._readTreeAndClose(...) binds the parser via assignAndReturnParser(...). The tree scan then applies Jackson's normal duplicate-property handling (last value wins) instead of dereferencing a null.

Test

GenericJacksonJsonRedisSerializerUnitTests.deserializeShouldHandleDuplicatePropertyWithDefaultTyping deserializes a value containing a duplicate property. It reproduces the NullPointerException above without the fix and passes with it.

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• There is a test case backing the change; no formatting-only changes are included.
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Closes #3396