apache/beam

In WithKeys, get coder for key more safely.

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#18,571 opened on Jun 3, 2022

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Description

In WithKeys.java currently the coder for the key type is chosen when the transform is expanded. This means that there's no way to directly get the type of the input elements, instead the type is inferred from the function or from a java Class<> object. This means there can be mismatches between the actual type of the input and the coder used.

WithKeys should be refactored to retrieve the coder in a safer way and avoid the possibility of mismatches.

Imported from Jira BEAM-3003. Original Jira may contain additional context. Reported by: danoliveira.

Contributor guide

Research direction
Examine the current implementation of WithKeys and understand how coders are inferred for key types. Identify the mismatch potential and propose a refactor to retrieve coders dynamically from the input elements instead of inferring from function or class objects.
Tech stack
java
Domain
backendapi
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
JavaApache Beam
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60