fix(miner): avoid XDPoS-only paths on non-XDPoS engines

[gzliudan]

Proposed changes

• Avoid panics in update() by guarding XDPoS-only channels when the engine is not XDPoS.
• Skip work commits when XDPoS config is enabled but the engine is not XDPoS, with height-based log throttling.
• Add regression tests for non-XDPoS update loop and XDPoS config/engine mismatch.

Types of changes

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• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update (if none of the other choices apply)
• Regular KTLO or any of the maintaince work. e.g code style
• CICD Improvement

Impacted Components

Which part of the codebase this PR will touch base on,

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• Consensus
• Account
• Network
• Geth
• Smart Contract
• External components
• Not sure (Please specify below)

Checklist

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• This PR has sufficient test coverage (unit/integration test) OR I have provided reason in the PR description for not having test coverage
• Provide an end-to-end test plan in the PR description on how to manually test it on the devnet/testnet.
• Tested the backwards compatibility.
• Tested with XDC nodes running this version co-exist with those running the previous version.
• Relevant documentation has been updated as part of this PR
• N/A

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[Copilot]

Pull request overview

Guards XDPoS-specific mining worker logic to avoid unsafe type assertions against w.engine when the consensus engine is not *XDPoS.XDPoS.

Changes:

• Adds an *XDPoS.XDPoS type assertion guard in worker.update() and reuses the asserted engine for channel access.
• Makes checkPreCommit() resilient to non-XDPoS engines by conditionally using XDPoS-specific parent selection and turn-check logic.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

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[Copilot]

Pull request overview

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

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[Copilot]

This test can pass without actually exercising worker.update if the goroutine doesn’t get scheduled promptly (e.g., under heavy CI load): the first select will hit time.After and succeed even if update never started. Add a small synchronization handshake (e.g., a started channel closed right before calling worker.update(), then wait for it with a timeout) so the test reliably asserts update is running before checking it doesn’t return early.

Suggested change

	done := make(chan struct{})
	go func() {
	worker.update()
	close(done)
	}()
	select {
	done := make(chan struct{})
	started := make(chan struct{})
	go func() {
	close(started)
	worker.update()
	close(done)
	}()
	select {
	case <-started:
	// worker.update has started; proceed with timing checks.
	case <-time.After(time.Second):
	t.Fatal("worker.update did not start in time")
	}
	select {