v0.15.6 — UTXO ghost-spender wedge fix (recommended upgrade)

[oskarszoon]

v0.15.6 — UTXO ghost-spender wedge fix (recommended upgrade)

Released: 2026-07-23
GitHub: https://github.com/bsv-blockchain/teranode/releases/tag/v0.15.6
Container: ghcr.io/bsv-blockchain/teranode:v0.15.6

Upgrade priority

Recommended — fixes a wedge scenario where the node stops advancing on a specific block and retries it forever.

Symptom to watch for

Node stuck on a block that will not validate. Both entry points wedge:

• Legacy sync (HandleBlockDirect) retries the same block indefinitely
• Catchup (CheckBlockSubtreesRequest) does the same

Subtree validation logs a fatal ProcessingError from checkCounterConflictingOnCurrentChain — the underlying error is TX_NOT_FOUND inside GetCounterConflictingTxHashes. The counter teranode_utxo_counter_conflicting_ghost_spends (new in v0.15.6) will increment on nodes that were affected once the fix is deployed and revisit the same slot.

Root cause

A multi-input transaction whose spends partially succeed but whose record is never created leaves parent outputs with a recorded spender that does not exist (a "ghost"). A later block containing a conflicting transaction over the same slot hits the ghost during counter-conflicting resolution and cannot progress.

What changed

• utxo: tolerate confirmed-absent ghost spenders in the counter-conflicting walk (probe fail-closed for live spenders with missing descendants), and heal the dangling spend during ProcessConflicting (fix(utxo): tolerate confirmed ghost spenders in counter-conflicting walk and heal their dangling spends #1325, closes subtreevalidation: tolerate a dangling spender ref in the counter-conflicting walk (minimal read-side unwedge) #1320)

Write-side cause tracked separately in #1214. main gets a different fix — this is a v0.15-line-only backport.

Known issues

None new.

Full changelog