txdb: handle malformed first coin cursor key #35248

pull CruzMolina wants to merge 1 commits into bitcoin:master from CruzMolina:txdb-cursor-malformed-key changing 2 files +21 −5

CruzMolina commented at 10:08 PM on May 8, 2026: none
Motivation

CCoinsViewDB::Cursor() caches the first coin key after seeking to the coin prefix. It checked that the underlying LevelDB iterator was valid, but ignored whether deserializing the first key succeeded.

CCoinsViewDBCursor::Next() already treats a failed key decode as an invalid cursor. The initial cursor setup should do the same.

Change

Make CCoinsViewDB::Cursor() mark the cursor invalid if the first key cannot be decoded.

Add a regression test covering a malformed first coin key.

Test
```
cmake --build build --target test_bitcoin
build/bin/test_bitcoin --run_test=coins_tests_dbbase
```

txdb: handle malformed first coin cursor key

CCoinsViewDB::Cursor() caches the first coin key after seeking to the coin prefix. It checked that the underlying LevelDB iterator was valid, but ignored whether deserializing the key succeeded.

CCoinsViewDBCursor::Next() already treats a failed key decode as an invalid cursor. Mirror that behavior during initial cursor setup so a malformed first coin key cannot leave the cursor reporting itself as valid with a stale cached key.

Add a regression test for the malformed first-key case.

309e1e1e03

DrahtBot added the label UTXO Db and Indexes on May 8, 2026
DrahtBot commented at 10:08 PM on May 8, 2026: contributor



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Code Coverage & Benchmarks

For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35248.



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maflcko commented at 6:46 AM on May 9, 2026: member

ai slop: A bot re-creating previous pull requests without any reference
maflcko closed this on May 9, 2026

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txdb: handle malformed first coin cursor key #35248

Motivation

Change

Test

Code Coverage & Benchmarks

Reviews