Add Array.slice and Array.splice for value type arrays

[ernestognw]

This PR implements JavaScript-like slice and splice functions for value type arrays (uint256[], bytes32[], address[]) in the OpenZeppelin Arrays library.

Key features:

• slice: Creates a new array containing elements from a specified range (non-mutating)
• splice: Modifies the original array in-place, keeping elements from a specified range (mutating)
• Both functions support start-only and start/end variants with proper bounds sanitization
• Uses memory-safe mcopy instruction for efficient array operations
• Includes comprehensive test coverage with both JavaScript and Solidity fuzz tests

Breaking change: Requires pragma bump to ^0.8.24 for Arrays and all dependent contracts to support the mcopy instruction.

This addresses issue #5723 and provides developers with familiar array manipulation utilities similar to JavaScript's Array methods.

PR Checklist

• Tests
• Documentation
• Changeset entry (run npx changeset add)

[changeset-bot]

🦋 Changeset detected

Latest commit: 38e8e88

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
openzeppelin-solidity	Minor

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Click here if you're a maintainer who wants to add another changeset to this PR

[coderabbitai]

Walkthrough

• Adds a minor changeset noting new Arrays slice/splice utilities for value-type arrays.
• Implements in-memory slice and in-place splice for uint256[], bytes32[], and address[] in contracts/utils/Arrays.sol, with start/end sanitization and memory-safe copies.
• Updates contracts/utils/Bytes.sol comments to state splice mirrors JavaScript Array.splice.
• Extends scripts/generate/templates/Arrays.js to generate slice/splice helpers for value types.
• Introduces Solidity tests (test/utils/Arrays.t.sol) validating slice/splice across types and ranges with assertion helpers.
• Refactors JavaScript tests to chai-as-promised “eventually” style and adds comprehensive slice/splice suites (test/utils/Arrays.test.js).

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title Check	✅ Passed	The title clearly and concisely summarizes the main change of the pull request by stating that Array.slice and Array.splice are being added for value type arrays, which matches the core of the implemented functionality.
Docstring Coverage	✅ Passed	No functions found in the changes. Docstring coverage check skipped.
Description Check	✅ Passed	The provided pull request description clearly outlines the addition of JavaScript-like slice and splice functions for value-type arrays, detailing both start-only and start/end variants, memory-safe implementations, comprehensive test coverage, and the required pragma bump, all of which directly correspond to the changes introduced across the Arrays library, templates, and tests.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[ernestognw]

The only downside of this PR is that we'd need to bump pragma of Arrays.sol to 0.8.24 to support mcopy (and its dependants)
I would say it's fine since we're bumping it in other places as well. If we decide to get this in 5.5 then it would go along all the other pragma bumps