feat: migrate GoBatch API to generics

[MasterOfBinary]

Summary

• migrate batch, source, and processor public APIs to generics (Batch[T], Item[T], Source[T], Processor[T])
• update built-in sources/processors and helper APIs (RunBatchAndWait[T], BatchConfig[T], ExecuteBatches[T])
• migrate tests/examples/docs to typed usage and normalize any style
• add v0.5.0 changelog entry with explicit migration notes, including homogeneous ExecuteBatches[T] behavior and type-changing pipeline guidance

Validation

• /Users/vaughn/go/bin/goimports -w $(rg --files --glob '*.go')
• go test -race -coverprofile=coverage.txt -covermode=atomic ./...
• go vet ./...
• /Users/vaughn/go/bin/golangci-lint run --timeout=3m

---

Note

High Risk
Wide-reaching breaking changes to all public interfaces and built-in implementations; downstream users must update type parameters and any custom Source/Processor implementations to compile.

Overview
Hard-breaking API migration to generics across the library. Core types and interfaces are now parameterized (Batch[T], Item[T], Source[T], Processor[T]), with Source.Read returning <-chan T and processors operating on []*Item[T].

All built-in sources/processors and helper utilities were updated to the typed API (RunBatchAndWait[T], BatchConfig[T], ExecuteBatches[T]), and the full docs/README/examples/tests were rewritten to use explicit type parameters (often any) with new v0.5.0 changelog + migration notes (including ExecuteBatches now requiring a single shared T per call).

^{Written by Cursor Bugbot for commit b625e7b. This will update automatically on new commits. Configure here.}

[gemini-code-assist]

Summary of Changes

Hello @MasterOfBinary, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly refactors the GoBatch library by introducing Go generics across its public API. This change aims to provide compile-time type safety for batch processing, eliminating the need for runtime type assertions and making the API more robust and easier to use. The migration impacts core data structures and interfaces, requiring users to specify types when creating batches, sources, and processors. This update also ensures that built-in components and helper functions are fully compatible with the new generic paradigm, streamlining the development of type-safe batch processing pipelines.

Highlights

• Generics Migration: The core Batch, Item, Source, and Processor APIs have been migrated to use Go generics, enhancing type safety and reducing the need for interface{} type assertions.
• Breaking Changes: This migration introduces breaking changes, requiring explicit type parameters for Batch[T], Item[T], Source[T], and Processor[T], as well as updates to method signatures like Source.Read and Processor.Process.
• Helper API Updates: Helper functions such as RunBatchAndWait, BatchConfig, and ExecuteBatches have been updated to support the new generic types.
• Built-in Component Adaptation: All built-in sources and processors (e.g., source.Channel, processor.Transform) now require explicit type parameters, and examples/tests have been updated accordingly.
• Changelog and Documentation: A new v0.5.0 changelog entry has been added, providing detailed migration notes, including guidance on homogeneous batch behavior and handling type-changing pipelines.

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Changelog

• CHANGELOG.md
  • Added new version 0.5.0 entry detailing breaking changes and migration steps for generics.
  • Updated Batch, Item, Source, and Processor to be generic types (Batch[T], Item[T], Source[T], Processor[T]).
  • Updated Source.Read to use typed output channels (<-chan T).
  • Updated Processor.Process to use typed items ([]*Item[T]).
  • Noted that built-in sources and processors now require explicit type parameters (e.g., source.Channel[int]).
  • Updated helper APIs RunBatchAndWait[T], BatchConfig[T], and ExecuteBatches[T] to generics.
  • Provided migration guidance for instantiating typed batches, sources, and processors.
  • Clarified requirements for ExecuteBatches[T] regarding shared T types.
  • Advised on using Batch[any] for pipelines that change data types between processor stages.
  • Instructed custom source and processor implementations to update their type signatures.

Activity

• No specific activity (comments, reviews, etc.) has been recorded for this pull request yet.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.79%. Comparing base (4d5378d) to head (b625e7b).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

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##           master      #60   +/-   ##
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  Coverage   96.79%   96.79%           
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  Files          12       12           
  Lines         374      374           
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  Hits          362      362           
  Misses          9        9           
  Partials        3        3           

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[gemini-code-assist]

Code Review

This is an excellent and thorough pull request that successfully migrates the entire library to use Go generics. The changes are extensive, consistent, and well-executed across the core API, tests, examples, and documentation. This migration significantly improves type safety and the overall developer experience. The code quality is high, demonstrating a strong understanding of generics and concurrent programming in Go. The updated documentation, especially the changelog with migration notes, is clear and will be very helpful for users transitioning to this new version. I have no suggestions for improvement.