BlockValidation - regenerate missing subtreemeta

[freemans13]

Problem

When getSubtreeMetaSlice() fails to find subtree meta files during block validation, blocks are incorrectly marked invalid even though the underlying subtree data exists to regenerate them. This occurs when:

• Blocks are validated during catchup (where meta creation is intentionally skipped for performance)
• Meta files have been pruned but subtree data still exists
• Operators manually revalidate old blocks after pruning

Solution

Add on-demand subtree meta regeneration that attempts to rebuild missing meta files from subtree data (local store first, then peer fallback).

Changes

1. Deleted model/tx_fetcher.go (~200 lines removed)

   • Merged subtreedata fetching logic directly into the regenerator
   • Removed unproven batch transaction API

2. Simplified model/subtree_meta_regenerator.go

   • Inlined local subtreedata fetching + peer HTTP fallback
   • Removed TxFetcherI interface dependency
   • Constructor: NewSubtreeMetaRegenerator(logger, subtreeStore, peerURLs, apiPrefix)

3. Simplified Block.Valid() signature

   • Removed functional options pattern (ValidationOptions, ValidationOption, WithMetaRegenerator)
   • Added metaRegenerator SubtreeMetaRegeneratorI as a regular nil-able parameter
   • Callers pass nil when regeneration not needed (e.g., block assembly)

4. Updated callers

   • BlockValidation.go / Server.go (blockvalidation): pass regenerator
   • Server.go (blockassembly): pass nil (just created the subtrees, no regeneration needed)
   • Test files: pass nil

Regeneration Flow

RegenerateMeta(subtreeHash, subtree)
    ├── Try local subtreedata store
    │   └── Success → build meta, store it, return
    ├── Try each peer URL
    │   └── GET /api/v1/subtree_data/{hash}
    │       └── Success → build meta, store it, return
    └── All failed → return error

Testing

• go test ./model/... -run SubtreeMeta - regenerator unit tests
• go test ./services/blockvalidation/... - integration tests
• make lint - passes

[github-actions]

🤖 Claude Code Review

Status: Complete

No issues found. All previously reported issues have been resolved:

✅ Fixed Issues:

• HTTP client timeout reduced from 5 minutes to 30 seconds (line 51)
• Error handling now differentiates between 404 and other HTTP errors (lines 113-117)

Review Summary:
This PR adds on-demand regeneration of missing subtree meta files during block validation. The implementation is well-structured with:

• Clean separation of concerns (local store → peer fallback)
• Comprehensive test coverage including local, peer, and failure scenarios
• Proper error handling and logging
• Non-blocking meta storage to avoid validation delays

The changes follow project conventions and integrate cleanly with existing validation flows.

[github-actions]

🤖 Claude Code Review

Status: Complete

---

Current Review:

All previous issues have been addressed:

• ✅ HTTP timeout reduced from 5 minutes to 30 seconds
• ✅ Error handling improved to differentiate between 404 and other HTTP errors

Minor Observation:

One potential defensive programming improvement (not a blocker):

• In buildMetaFromSubtreeData (model/subtree_meta_regenerator.go:146), accessing subtree.Nodes[0] without checking len(subtree.Nodes) > 0 could theoretically panic if called with an empty subtree. While this may never occur in practice (subtrees always have at least a coinbase placeholder), adding a length check would make the code more defensive.

Summary: The implementation is solid. The regeneration logic is well-structured with local-first fallback to peers, comprehensive test coverage (7 test cases), and proper error handling. The design correctly uses warn-level logging for regeneration events since this is an exceptional but valid scenario.

History:

• ✅ Fixed: HTTP timeout reduced to 30s (was 5 minutes)
• ✅ Fixed: Error handling now distinguishes 404 from other HTTP errors

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
82.3% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud