downloader: fix edgecase where returned index is OOB for downloader (#18335)

* downloader: fix edgecase where returned index is OOB for downloader

* downloader: documentation

Co-Authored-By: holiman <martin@swende.se>
This commit is contained in:
Martin Holst Swende 2018-12-20 10:46:08 +01:00 committed by GitHub
parent fe86a707d8
commit 5f251a6448
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@ -1488,7 +1488,15 @@ func (d *Downloader) importBlockResults(results []*fetchResult) error {
blocks[i] = types.NewBlockWithHeader(result.Header).WithBody(result.Transactions, result.Uncles)
}
if index, err := d.blockchain.InsertChain(blocks); err != nil {
if index < len(results) {
log.Debug("Downloaded item processing failed", "number", results[index].Header.Number, "hash", results[index].Header.Hash(), "err", err)
} else {
// The InsertChain method in blockchain.go will sometimes return an out-of-bounds index,
// when it needs to preprocess blocks to import a sidechain.
// The importer will put together a new list of blocks to import, which is a superset
// of the blocks delivered from the downloader, and the indexing will be off.
log.Debug("Downloaded item processing failed on sidechain import", "index", index, "err", err)
}
return errInvalidChain
}
return nil