fix: improve miner thread robustness

[brice-stacks]

Fixed the miner thread exiting (and stalling the chain for the remainder of the tenure) on transient error. The miner now retries when it hits DB contention, a parent block that has not been processed yet, a new parent block discovered mid-mining, or a mempool cache reset failure, instead of giving up on the tenure.

These changes are difficult to test and not worth the effort in my opinion.
Never mind -- this does need testing. I'm working on it.

Checklist

• Test coverage for new or modified code paths
• For new Clarity features or consensus changes, add property tests (see
  docs/property-testing.md)
• Changelog fragment(s) or "no changelog" label added (see
  changelog.d/README.md). If this PR breaks
  anything for node operators or users, or requires them to manually do
  anything (such as adjust a setting), use the breaking category.
• Required documentation changes (e.g.,
  rpc/openapi.yaml for RPC endpoints,
  event-dispatcher.md for new events)
• New clarity functions have corresponding PR in clarity-benchmarking repo

[Copilot]

Pull request overview

Improves miner resilience by retrying recoverable failures instead of ending the tenure’s mining thread.

Changes:

• Adds abort-aware retry handling for parent changes, DB errors, and timestamp validation.
• Retries failed mempool cache resets.
• Preserves underlying DB errors for retry classification.

Reviewed changes

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

File	Description
stacks-node/src/nakamoto_node/miner.rs	Adds miner retry and abort behavior.
changelog.d/miner-thread-retry-transient-errors.fixed	Documents the robustness fix.

Suppressed comments (1)

stacks-node/src/nakamoto_node/miner.rs:826

• This arm classifies all DBError values as transient, but the wrapped error type also includes permanent conditions such as Corruption, ReadOnly, OldSchema, TooOldForEpoch, and BlockHeightOutOfRange (stackslib/src/util_lib/db.rs:54-91). Such faults will now loop and log until the tenure changes. Narrow this arm to explicitly retryable contention errors (and any intentionally retryable not-found cases), allowing all other errors to reach the fatal path.

            Err(
                ref e @ (NakamotoNodeError::MiningFailure(ChainstateError::DBError(_))
                | NakamotoNodeError::DBError(_)),

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[brice-stacks]

I don't think it hurts anything if the miner keeps retrying with no possibility of recovery, and that case might be more obvious in the logs. I'll take a closer look.

[cylewitruk-stacks]

Only thing that I'd be careful of is the potential for this warn! to spam the logs 5x/second if it is e.g. some db/storage (or other persistent) issue 🙈 But the expect() above would maybe crash the thread then..

EDIT: But I guess we do that in a bunch of other places here already, so likely moot. I don't think it hurts anything, either -- the node will crash for other reasons if out of space or there's a corrupt db somewhere, etc.

[coveralls]

Coverage Report for CI Build 32298405099

Coverage decreased (-0.01%) to 86.59%

Details

• Coverage decreased (-0.01%) from the base build.
• Patch coverage: 10 uncovered changes across 1 file (95 of 105 lines covered, 90.48%).
• 135 coverage regressions across 33 files.

Uncovered Changes

File	Changed	Covered	%
stacks-node/src/nakamoto_node/miner.rs	101	91	90.1%
Total (2 files)	105	95	90.48%

Coverage Regressions

135 previously-covered lines in 33 files lost coverage.

Top 10 Files by Coverage Loss	Lines Losing Coverage	Coverage
stackslib/src/net/p2p.rs	25	73.93%
stacks-node/src/nakamoto_node/miner.rs	13	86.78%
stackslib/src/net/inv/epoch2x.rs	10	80.01%
stacks-node/src/nakamoto_node/relayer.rs	9	86.26%
stackslib/src/burnchains/burnchain.rs	8	71.39%
stackslib/src/net/stackerdb/sync.rs	6	76.37%
stacks-node/src/neon_node.rs	6	83.33%
stacks-signer/src/v0/signer_state.rs	6	92.95%
stackslib/src/chainstate/stacks/index/marf.rs	5	84.07%
stackslib/src/net/mod.rs	4	78.01%

---

Coverage Stats

Relevant Lines:	233083
Covered Lines:	201827
Line Coverage:	86.59%
Coverage Strength:	19408614.31 hits per line

---

💛 - Coveralls

[cylewitruk-stacks]

At a first glance this lgtm 👍 Not approving just yet only because I want to circle back with more focus and follow the error paths more closely.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Suppressed comments (1)

stacks-node/src/tests/nakamoto_integrations.rs:19784

• These errors are all injected at the start of mine_block(), before parent loading, cache reset, block building, and the post-broadcast processing wait. The test therefore covers only the top-level match arms; it cannot catch regressions in the newly added DB retry inside wait_for_last_block_mined_and_processed() or retry behavior after an actual cache-reset failure. Add operation-specific fault points so those production paths fail once and then recover within the same tenure.

    TEST_MINE_TRANSIENT_ERRORS.set(vec![
        TestTransientError::ParentNotFound,
        TestTransientError::NewParentDiscovered,
        TestTransientError::DBError,
    ]);

[francesco-stacks]

LGTM!