Fix Python Flink PVR

[shunping]

fixes #36326

The workflow (https://github.com/apache/beam/actions/workflows/beam_PreCommit_Python_PVR_Flink.yml) started to fail after #37969.

[gemini-code-assist]

Summary of Changes

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This pull request addresses a regression in Python Flink PVR tests caused by an upgrade to Jackson 2.14+. By moving away from a static, shared deserialization context and instead creating fresh, parser-associated contexts during deserialization, the changes resolve NullPointerExceptions that occurred when deserializers attempted to access transient parser fields.

Highlights

• Jackson Deserialization Fix: Replaced the static DESERIALIZATION_CONTEXT with a dynamic creation approach to prevent NullPointerExceptions in Jackson 2.14+.
• Context Initialization: Updated deserialization logic to properly associate contexts with active parsers instead of using copy(), which was causing issues with transient parser fields.
• Test Trigger: Added a trivial change to the trigger file to ensure the Python Flink PVR test suite runs.

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[shunping]

Looks promising: https://github.com/apache/beam/actions/runs/26058338647/job/76611930336?pr=38531

[shunping]

r: @Abacn @aIbrahiim @stankiewicz

[github-actions]

Stopping reviewer notifications for this pull request: review requested by someone other than the bot, ceding control. If you'd like to restart, comment assign set of reviewers

[gemini-code-assist]

Code Review

This pull request addresses potential NullPointerExceptions in Jackson 2.14+ by ensuring that DefaultDeserializationContext is properly initialized with a parser instead of using the copy() method, which leaves the transient parser field null. The changes are applied in PipelineOptionsFactory.java within the computeDeserializerForMethod and deserializeNode methods. Feedback from the review suggests centralizing the context creation logic into a private helper method to reduce code duplication and improve maintainability.