XDC Random Value

[batrr]

XDC uses the block number as a random number, not the difficulty.

Changes

• Add BlockExecutionContext.WithPrevRandao static factory for custom RNG injection
• Override CreateBlockExecutionContext to pass xdc specific PREVRANDAO xdc

Types of changes

What types of changes does your code introduce?

• Bugfix (a non-breaking change that fixes an issue)
• New feature (a non-breaking change that adds functionality)
• Breaking change (a change that causes existing functionality not to work as expected)
• Optimization
• Refactoring
• Documentation update
• Build-related changes
• Other: Description

[github-actions]

EVM Opcode Benchmark Diff

Aggregated runs: base=1, pr=1

No significant regressions or improvements detected.

[Copilot]

Pull request overview

This PR adds an extension point for customizing the EVM BlockExecutionContext per chain, and uses it to inject an XDC-specific PREVRANDAO value during block processing.

Changes:

• Added BlockExecutionContext.WithPrevRandao(...) factory to allow custom PREVRANDAO injection.
• Added BlockProcessor.CreateBlockExecutionContext(...) (virtual) and routed transaction execution through it.
• Overrode CreateBlockExecutionContext in XdcBlockProcessor to provide an XDC-specific PREVRANDAO value derived from the block number.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
src/Nethermind/Nethermind.Xdc/XdcBlockProcessor.cs	Overrides block execution context creation to inject an XDC-specific PREVRANDAO.
src/Nethermind/Nethermind.Evm/BlockExecutionContext.cs	Refactors BlockExecutionContext construction and adds a WithPrevRandao factory for custom RNG injection.
src/Nethermind/Nethermind.Consensus/Processing/BlockProcessor.cs	Introduces a virtual hook for creating BlockExecutionContext and uses it when setting up transaction execution.

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[alexb5dh]

So for block value of 0 (which we probably won't hit?) I think it will be different from XDC version, as big.Int.Bytes() returns [] in Go, while our version returns [0].

But in general, +1 for a test comparing this function output against static pre-computed XDC values for a few inputs, as I'm not so confident our ToBigEndianSpanWithoutLeadingZeros always matches big.Int.Bytes().