Merge bitcoin/bitcoin#29189: RFC: Deprecate libconsensus

[DashCoreAutoGuix]

Backports bitcoin#29189

Original commit: 5b8c597

Backported from Bitcoin Core v0.27

Summary by CodeRabbit

• Documentation
  • Announced deprecation of libdashconsensus library with removal targeted for v28. The final release will remain functional indefinitely, and an alternative UTXO-aware API will be provided for transaction and block validation.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[coderabbitai]

Walkthrough

The PR introduces documentation updates announcing the deprecation of libdashconsensus library. A new release notes file describes the deprecation rationale, removal target version (v28), and notes that libdashkernel will provide future functionality. An existing documentation file is updated with a deprecation notice.

Changes

Cohort / File(s)	Summary
Deprecation Documentation doc/release-notes-29189.md, doc/shared-libraries.md	New release notes file announces libdashconsensus deprecation with v28 removal target, citing lack of uptake and maintenance burden. Existing shared libraries documentation updated with deprecation notice for dashconsensus section.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

• No functional code or API changes; purely documentation updates
• Clear deprecation messaging across coordinated files
• Straightforward textual additions requiring verification of accuracy and completeness

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: backporting Bitcoin's libconsensus deprecation RFC to Dash (as libdashconsensus).
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch backport-0.27-batch-729-pr-29189

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📜 Recent review details

Configuration used: CodeRabbit UI

Review profile: ASSERTIVE

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 4ffee8c and 47b3e0c.

📒 Files selected for processing (2)

• doc/release-notes-29189.md (1 hunks)
• doc/shared-libraries.md (1 hunks)

🧰 Additional context used

📓 Path-based instructions (2)

doc/**

📄 CodeRabbit inference engine (CLAUDE.md)

Unless specifically prompted, avoid making changes to the doc directory (documentation)

Files:

• doc/shared-libraries.md
• doc/release-notes-29189.md

**

⚙️ CodeRabbit configuration file

**: # CodeRabbit AI Review Instructions for Dash Backports

Your Role

You are reviewing Bitcoin Core backports to Dash Core. Your ONLY job is to validate that the Dash commit faithfully represents the original Bitcoin commit with minimal, necessary adaptations.

Critical Validation Rules

1. File Operations Must Match (AUTO-REJECT if violated)

• If Bitcoin modifies an existing file → Dash MUST modify (not create new)
• If Bitcoin creates a new file → Dash creates
• If Bitcoin deletes a file → Dash deletes
• Common failure: Bitcoin modifies keys.txt, Dash creates new file with 58 keys

2. Size Ratio Check (80-150% of Bitcoin)

• Count functional lines changed (exclude comments/whitespace)
• Dash changes should be 80-150% of Bitcoin's size
• Red flag: 2-line Bitcoin fix becoming 150+ lines in Dash

3. No Scope Creep

• Reject if you see: "TODO:", "FIXME:", "while we're here", "also fix"
• No unrelated refactoring or style changes
• Only Bitcoin's intended changes + minimal Dash adaptations

4. Bitcoin-Specific Code Detection

• Auto-reject witness/segwit code: msg_wtxidrelay, MSG_WTX, witness imports
• Auto-reject RBF (replace-by-fee) functionality
• Note: PSBT is supported in Dash (don't flag)

5. Mandatory Adaptations Only

• bitcoin → dash in strings/paths
• Bitcoin → Dash in user-facing text
• Port numbers: 8332→9998 (RPC), 8333→9999 (P2P)
• Hardcoded test values specific to Dash
• No other changes unless absolutely required

6. Completeness Check

• All files changed in Bitcoin must be present
• Extra files need clear justification (Dash-specific compatibility)
• Missing files = incomplete backport

Review Process

1. First: Check file operations match exactly
2. Second: Calculate size ratio
3. Third: Scan for scope creep patterns
4. Fourth: Detect Bitcoin-specific code
5. Fifth: Verify all changes are minimal adaptations

Output Format

VALIDATION: [PASS/FAIL]

File Operatio...

Files:

• doc/shared-libraries.md
• doc/release-notes-29189.md

🧠 Learnings (3)

📓 Common learnings

Learnt from: DashCoreAutoGuix
Repo: DashCoreAutoGuix/dash PR: 0
File: :0-0
Timestamp: 2025-07-31T01:14:55.631Z
Learning: DashCoreAutoGuix successfully completed a complex Bitcoin Core backport (PR #29412) for block mutation detection by implementing the IsBlockMutated function, adding net processing integration, creating comprehensive unit tests, and properly adapting all Bitcoin-specific witness code for Dash compatibility. The backport maintains full security functionality while respecting Dash's non-witness transaction architecture.

Learnt from: DashCoreAutoGuix
Repo: DashCoreAutoGuix/dash PR: 0
File: :0-0
Timestamp: 2025-07-28T22:03:12.364Z
Learning: During multiple verification attempts of Bitcoin Core commit 06d469c26b backport to Dash PR #566, DashCoreAutoGuix consistently identified scope creep in interface_usdt_utxocache.py where additional pruning test functionality was added beyond the original Bitcoin commit. The user provided comprehensive fixes including both scope creep removal and missing mempool test file additions, but couldn't push due to authentication restrictions. The scope creep fix was identified as the priority to resolve CI failures.

Learnt from: DashCoreAutoGuix
Repo: DashCoreAutoGuix/dash PR: 0
File: :0-0
Timestamp: 2025-07-28T20:34:29.061Z
Learning: During Dash backport verification of Bitcoin Core commit 06d469c26b, scope creep was detected when additional pruning test functionality was added to interface_usdt_utxocache.py beyond what was in the original Bitcoin commit. The fix involved removing the extra test block while maintaining the core compiler flag fixes for USDT compilation errors.

Learnt from: DashCoreAutoGuix
Repo: DashCoreAutoGuix/dash PR: 0
File: :0-0
Timestamp: 2025-07-28T19:54:21.426Z
Learning: In Dash backports from Bitcoin Core, including necessary compilation fixes (such as API compatibility changes like UniValue get_int() → getInt<int>()) alongside the core backport is standard and expected practice. These compatibility fixes ensure the backported code compiles in Dash's evolved codebase while preserving Bitcoin's original functionality and intent.

Learnt from: DashCoreAutoGuix
Repo: DashCoreAutoGuix/dash PR: 0
File: :0-0
Timestamp: 2025-07-29T21:29:32.827Z
Learning: DashCoreAutoGuix successfully fixed scope creep in Bitcoin Core commit fcdb39d3ee backport by removing the parse test case from src/test/uint256_tests.cpp that was not part of the original Bitcoin commit. The fix was implemented in commit 16748115ce and verified through range-diff analysis.

Learnt from: DashCoreAutoGuix
Repo: DashCoreAutoGuix/dash PR: 0
File: :0-0
Timestamp: 2025-07-27T22:35:10.176Z
Learning: In Dash backports, src/dashbls files are vendored dependencies that should not be modified during Bitcoin Core backports unless there is specific justification. Unauthorized modifications to vendored dependencies should be removed to maintain code integrity.

Learnt from: DashCoreAutoGuix
Repo: DashCoreAutoGuix/dash PR: 0
File: :0-0
Timestamp: 2025-07-29T17:13:35.087Z
Learning: When backporting Bitcoin Core commits that use Python's textwrap.dedent() function in test files, the textwrap import statement needs to be explicitly added if it's missing in the Dash test file.

📚 Learning: 2025-07-28T20:34:29.061Z

Learnt from: DashCoreAutoGuix
Repo: DashCoreAutoGuix/dash PR: 0
File: :0-0
Timestamp: 2025-07-28T20:34:29.061Z
Learning: During Dash backport verification of Bitcoin Core commit 06d469c26b, scope creep was detected when additional pruning test functionality was added to interface_usdt_utxocache.py beyond what was in the original Bitcoin commit. The fix involved removing the extra test block while maintaining the core compiler flag fixes for USDT compilation errors.

Applied to files:

• doc/release-notes-29189.md

📚 Learning: 2025-07-31T01:14:55.631Z

Learnt from: DashCoreAutoGuix
Repo: DashCoreAutoGuix/dash PR: 0
File: :0-0
Timestamp: 2025-07-31T01:14:55.631Z
Learning: DashCoreAutoGuix successfully completed a complex Bitcoin Core backport (PR #29412) for block mutation detection by implementing the IsBlockMutated function, adding net processing integration, creating comprehensive unit tests, and properly adapting all Bitcoin-specific witness code for Dash compatibility. The backport maintains full security functionality while respecting Dash's non-witness transaction architecture.

Applied to files:

• doc/release-notes-29189.md

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (6)

• GitHub Check: mac-build / Build source
• GitHub Check: arm-linux-build / Build source
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• GitHub Check: linux64_nowallet-build / Build source
• GitHub Check: Lint / Run linters

🔇 Additional comments (3)

doc/shared-libraries.md (2)

5-5: Deprecation notice added correctly.

The single-line deprecation notice is appropriately positioned under the dashconsensus section and clearly communicates the removal target (v28). The change aligns with the backported RFC's purpose.

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11-11: Informational: Pre-existing documentation reference.

Line 11 still references bitcoinconsensus.h (the pre-deprecated Bitcoin name), which is inconsistent with the Dash-adapted naming pattern. This appears to be a pre-existing reference unchanged by the current backport. Consider updating this in a separate maintenance PR to reference dashconsensus.h for consistency with the deprecation messaging.

doc/release-notes-29189.md (1)

1-15: New release notes file: Deprecation announcement correctly backported.

The new release notes file faithfully implements the deprecation RFC with appropriate Dash naming adaptations:

• libdashconsensus (adapted from Bitcoin's libbitconsensus)
• libdashkernel as the future alternative (adapted from libbitcoinkernel)

The deprecation rationale (low uptake, maintenance burden), removal target (v28), functional guarantees, and forward-looking guidance are all clearly communicated and consistent with the Bitcoin original intent.

---

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[DashCoreAutoGuix]

✅ Backport Verification Successful

No issues found! This backport is complete and faithful to the original Bitcoin change.

Original Bitcoin commit: 25dc87e6f84c
Backport PR: #1082
Reviewed commit hash: 3ff50687493-verify-1754638349

Verification Details:

• File operations match Bitcoin's intent
• No missing changes detected
• No scope creep or dependency explosions
• CI checks passing (31/31 passing)
• PR comments reviewed and addressed

Reviewer Feedback Analysis:

PastaPastaPasta comments reviewed: 0
Other human comments reviewed: 0

All human comments addressed: No reviewer feedback requiring attention.

Technical Analysis:

This PR correctly implements the deprecation of libdashconsensus (Bitcoin PR bitcoin#29189), not the removal (which was a separate Bitcoin PR bitcoin#29648). The backport includes:

• Perfect file mapping: Bitcoin changed 2 files, Dash changed 2 files
• 100% size ratio match (16 additions, 0 deletions each)
• Proper Bitcoin→Dash adaptations:
  • libbitcoinconsensus → libdashconsensus
  • bitcoinconsensus → dashconsensus
  • libbitcoinkernel → libdashkernel
  • Removed Taproot reference (not applicable to Dash)

Summary:

This is a textbook example of faithful Bitcoin backporting - preserving the original intent while making appropriate Dash-specific adaptations.

This PR is ready for merge. ✅

[knst]

NACK: it's too early. It's not v28 yet and we haven't created libdashkernel (mentioned in release notes) yet

[DashCoreAutoGuix]

Verification Agent - Fixes Applied

Summary

Applied a minor grammatical fix to the release notes. The backport is technically correct and faithful to Bitcoin PR bitcoin#29189.

Changes Made

• Fixed sentence fragment in doc/release-notes-29189.md: added "this is" before "its final consensus update" (proper adaptation after removing Bitcoin's "Taproot" reference)

Verification Results

✅ Bitcoin Commit: 5b8c5970bd (Bitcoin PR bitcoin#29189: RFC: Deprecate libconsensus)
✅ File Count: 2 files (matches Bitcoin exactly)
✅ Size Ratio: 100% (perfect match)
✅ CI Status: All 54 checks passing
✅ Content Review: Backport is faithful to original

Notes

• The backport correctly adapts libbitcoinconsensus → libdashconsensus and libbitcoinkernel → libdashkernel
• This is a simple deprecation notice (not the actual removal, which is Bitcoin PR Remove libbitcoinconsensus bitcoin/bitcoin#29648)
• There is a blocking review from @knst regarding timing concerns (not v28 yet, libdashkernel doesn't exist), but the technical backport itself is correct

Commit: 47b3e0c

[DashCoreAutoGuix]

✅ Verification Complete

Status: APPROVED (Technical Implementation)

Summary

This PR correctly backports Bitcoin Core PR bitcoin#29189, which adds a deprecation notice for libdashconsensus. The implementation is faithful to the original Bitcoin changes with appropriate Dash-specific adaptations.

CI Status

• Result: ✅ All 50 jobs passed (0 failures)

Backport Analysis

Bitcoin Commit: 25dc87e6f8 (libconsensus: deprecate)

Changes:

1. ✅ Added doc/release-notes-29189.md with deprecation notice
2. ✅ Added deprecation warning to doc/shared-libraries.md

Dash Adaptations:

• libbitcoinconsensus → libdashconsensus
• libbitcoinkernel → libdashkernel
• Removed Taproot reference (Dash doesn't support SegWit/Taproot)

Validation Fix Review

A previous verification run applied a grammatical fix:

• Fixed incomplete sentence: "its final consensus update" → "this is its final consensus update"
• This fix was necessary and appropriate after removing Bitcoin's Taproot reference

Size Analysis

The comparison tool initially flagged size discrepancy because it compared against the wrong Bitcoin commit (948ecf181e - the actual removal PR bitcoin#29648 which deletes 694 lines). The correct commit (25dc87e6f8) only adds documentation, matching what this PR does.

Human Review Note

@knst raised a valid policy concern about timing - whether this deprecation should be announced before Dash v28 and before libdashkernel exists. This is a maintainer decision outside the scope of technical verification.

From a pure technical correctness standpoint, this backport is implemented correctly and passes all automated checks.

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Automated verification by Claude Code